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Soil Testing

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  • 1. Certificate Course in Agricultural BiotechnologyBIOFERTILIZER TECHNOLOGY Institute team: Dr. B.K.Datta Dr. R.Datta Dr. S.K.Das Dr. S.K.Si Mr. S. Sahoo Mr. D. Biswas Mr. S. Giri Mr. T. Nayek Expert Consultants: Dr. P.K. Singh, IRAI, New Delhi Dr. O.P. Rupela, ICRISAT, Hyderabad Dr. R.K.Basak, BCKV, Mohanpur, W.B Dr. D.J. Bagyaraj, Univ. of Agric. Sciences, Bangalore Dr. R. Kale, Univ. of Agric. Sciences, Bangalore Dr. Sunil Pabbi, IARI, New Delhi Dr. Aloke Adholeya, TERI, New Delhi Vivekananda Institute of Biotechnology
  • 2. First published in July, 2004by Vivekananda Institute of BiotechnologyNimpith, South 24 Parganas, West Bengal, IndiaDesigned by Tellywallah, CalcuttaPrinted by Swapna Printing Works Private Limited, CalcuttaAll rights reserved.c Vivekananda Institute of Biotechnology, 2004This manual is sold subject to the condition that it shall not, by way of trade or otherwise,be lent, resold, hired out or otherwise circulated without the publishers prior consentin any form of binding or cover other than that in which it is published.
  • 3. ForewordFifty years back a monk, Swami Buddhanandji, was deeply inspired by SwamiVivekananda’s ideals. He started a different kind of journey of life and a seedof development was sown at Nimpith. Late Swami Buddhanandaji establishedthis Ashram. Vivekananda Institute of Biotechnology is a branch of that tree. TheInstitute initiated its activities in 1991. Its aim is to develop an advanced,functional, research as well as a resource center for the people of the Sunderbans.One of the chosen fields is Agricultural Biotechnology. For the last few years theInstitute has been implementing programmes on entrepreneurship development,in this field, in rural areas. The present manual is one of such activity to supportthis programme, which is the need of the hour. The Department of Science and Technology, Govt of India and UnitedNations Development Programme have come forward benevolently in bringingout this manual. It is a result of the combined efforts of scientists at our Instituteand of other National Institutes and Universities. Senior scientists like Dr.P.K.Singh, Dr. O.P.Rupela, Dr. Radha Kale, Dr. Ranjan Basak, Dr. Sunil Pabbi,Dr. D.J. Bhagyaraj and Dr. Alok Adholeya have enriched this effort by theirvaluable guidance and by sharing their experience . Shri Gautam Bose, Shri AmitKumar and Shri Pradip Nair of Tellywallah have worked hard and extensively tomake it in this present form. We hope that this great effort will be used by the rural agro-biotechnologists,whose services, we believe, will bring a new dawn to rural India.Nimpith Swami SadanandaJuly 2004 Chairman
  • 4. PrefaceIn today’s world, technology is moving very fast, in certain sectors at a fasterpace. Biotechnology is such an area. The rural India which is depending onagriculture for its day to day life provides an immense market for new technologies.The only condition is the proper training and marketing. The present manual is the outcome of the project ‘Technical HumanResource Development – Vocational Training For Employment Generation’supported by UNDP & DST, Govt. of India. The objective of the programme isto develop human resources through competency based training in innovativeareas for the production and service sectors in new, high technology areas basedon market needs. Agricultural biotechnology is the area in which we have worked on underthis project. This manual is first of its kind in this series. It deals with BiofertilizerTechnology which has six modules - Soil testing and fertilizer recommendation,Production and Application of Blue-green algae, Azolla, Microbial inoculants,Vesicular Arbuscular Mycorrhiza and Vermicompost. The target are the rural youth, who have passed their 10th std. It isdesigned and presented in such a way that a complicated subject like soil testingor microbial inoculant production becomes an easily adaptable skill, a demystificationof technology indeed. All the techniques mentioned here are of world standardbut no doubt many other options can also be opted for, for instance, in thesection of microbial inoculant production only the use of vessel is mentioned inthis manual though the use of other types of fermentors or shakers are alsopossible. This effort is the result of hard work of a team of our Institute, the samewas complemented by experts of other organizations, which are of world repute.Mr. Khudiram Sardar, Mr. Diwakar Haldar, , Mr.Tarun Das, Mr. Deepankar Haldar,Mr.Tapan Haldar and Mr. Shubankar Malik have helped while filming the experimentsfor this manual. Shri Gautam Bose , Shri Amit Kumar, Shri Pradip Nair and Shri ParthaBhattacharya of Tellywallah gave their best to make this dream a reality byfilming, designing, adding inputs and finally printing the manual.Nimpith Dr. B.K. DattaJuly 2004 Principal Scientist, VIB
  • 5. Using this manual This manual has been written to complement classroom lectures pertaining to the Biofertilizer Technology Section of the “Certificate Course in Agricultural Biotechnology” taught at the Vivekananda Institute of Biotechnology — VIB. However, it may also be read by anyone with school level knowledge of Science who is interested in setting up a soil testing lab or a microbial inoculant production facility. We have departed from traditional styles of writing Course material. Instead of dry and forbidding lists of procedures and equations, the manual tries to expose the student to the various aspects of the three disciplines that this course straddles — Microbiology, Agricultural Science and Chemistry. Of course, one cannot entirely avoid equations and procedures! But we felt it is possible to present these topics in a friendlier manner. Our approach to making the subject “friendlier” and also maintaining sufficient scientific detail was two-pronged. We’ve split the material being discussed into two parts — quite literally. The odd-numbered pages in this manual contain descriptions of experiments and processes in a step-by-step manner, devoid of detailed explanations — rather like a traditional lab manual which expects students to follow the steps described bothering to evoke an interest in the topic at hand. The objective of the VIB course was the opposite. As scientists we are amazed and intrigued by our respective fields of study. We wanted the reader to feel this amazement as well; to undestand that science is an exciting subject! To help us out, we enlisted the help of Shubham, an inquisitive, imaginary friend, who can’t stop asking questions. Shubham can be found loitering around on the even-numbered pages — asking questions about the text on the facing page. The even-numbered pages also contain supplementary information about the topic at hand. Definitions, little bits of trivia, brief forays into the history of science, suggestions for further reading, tips on how to simplify a process and so on may also be found on even numbered pages. The course material was meant to enable an interested student set up his own Soil Testing Centre and an Inoculant Production Centre. Which is why the material in this manual is presented in a “modular” fashion — typical of industrial processes. Therefore, operations like autoclaving, working in a Laminar Flow Cabinet and using a Fermentor have been dealt with in a separate section. The step-by-step description concentrates on following the process being discussed segment-wise. The line at the bottom of each odd-numbered page is a “station map”. This helps the students to see the “whole railway line” and on which station he stands — this is typical of any industrial process where one goes from A (A test tube of bacteria) to B (application of the inoculant in the field) and the various stages that must be crossed to do so.
  • 6. Using this manual In sections where extra explanation on the left hand pages was unnecessary,the step-by-step description continues. Addressing the reader directly (”You could then....” “We might look atthis from another angle....”) is something most textbooks never do but we feltthere was no reason why the manual should not attempt to make the readerfeel as if he was in a classroom while reading it. The manual is accompanied by an interactive CD-ROM. This contains allthe course material viewable in a non-linear fashion. This enables a studentto quickly refer to topics without having to flip through the manual. Further, allthe “modules” that are part of the production process, were filmed during themaking of this manual and the footage, with narration, is available on the CD.This could be used in the classroom too, during, say, the first time the topicis brought up for discussion by the instructor. The glossary in this manual is available in a searchable format on theCD-ROM.The CD-ROM contains two computer programmes written specifically for SoilTesting Centres. Chemicalc and X-Base are a scientific formula calculator anda Soil Database, respectively. X-Base allows Soil Testing Centres to share theirdata over the Internet with no additional software or hardware requirementsapart from a very rudimentary computer system and a telephone line. A few of the pages also contain material that is not immediately relevantto the course (eg., a brief description of the gene cascade in R.Meliloti that leadsto the production of nitrogenase, may be found in the pages that describeRhizobia). These portions are italicised. These sections are rare and are onlyfound, if at all, in the introductory part of the section. These could, if nothingelse, be food for thought for an inquisitive reader. Biotechnology is the fastest growing scientific field around the world. Asscientists around the world learn more about the amazing internal workings ofliving things, literature — this manual included — needs to be updated with aregularity, which, to a scientist, is more exciting than monotonous. The authorswould greatly appreciate any feedback about this manual. VIB hopes that this initiative will help fuel the next agricultural revolutionin our country — one powered not just by fertilizers and technology but also bya more aware and knowledgable farmer who understands the science behindthe word biotechnology... VIB team Nimpith July 2004
  • 7. Soil Testing - Collection and preparation of soil samplesComposite soil samples, packed for lab. analysis 1-1
  • 8. Introduction..A bit about the Soil Collection Process The process of soil testing begins in the field — where collection of samples is done. This needs to be done methodically — to ensure that the samples taken from the field represent the soil characteristics of the entire field. The process stated here is simple and easy to follow — though it does seemelaborate when you first read about it! Locating areas to take samples... Start at the bottom -left corner of the field and walk along the path indicated by the arrows. Along the way, mark areas (with a piece of wood — or anything easy to locate) from where you will be taking soil samples. Avoid marking prohibited areas (see the next page). The marked areas are shown in Red in the figure. Notice, that the red dots along the path are not necessarily on the path itself. That’s perfect — because this is a random sample. Apparatus required Plastic bucket, spade and wooden stakes or markers. Why is it necessary to go through such an elaborate process? It’s quite simple — ideally you’d want to test all the soil in your field — but that would take a lot of time. So, it becomes necessary to take samples from different places in the field. But how do you ensure that the samples taken to the testing centre represent, more or less, the soil in the field? The answer is the reason behind the elaborate process. By taking samples from randomly selected spots, you ensure thatyour cumulative soil sample represents the soil in most areas of the field. Thezig zag walk is just to establish a technique of selecting random spots.1-2 Collection and Preparation of soil samples
  • 9. Collecting soil samples The locations from where soil samples are taken may be marked by wooden stakes as shown. The stakes need not be numbered. The locations are chosen by walking along a zig-zag path starting at any corner of the field. These are marked by white spots in the picture. A typical location is shown in the next picture. Each collection location needs to be cleared of vegetation and dust. This is done by scraping away a very thin layer of soil.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-3
  • 10. Prohibited samples... Prohibited Samples? It’s just another thing to do with the statistics (see page 2.1). Your soil samples need to represent the average soil characteristic of the field. However, every field has areas in it that tend to distort the average characteristic because the soil there has properties very different from the rest of the soil. (It’s called deviation from the mean, by the way) So, you need to ignore these areas when collecting samples.These include— Areas near gates, farmways, buildings etc. and areas on crop hills and in rows.— Areas where organic/chemical manure is or was kept.— Areas which are permanently in the shade.Why must the pit be 6” (15 cm) deep?6” is the depth of tillage i.e., the depth up to which the root system of the croppenetrates. Since soil testing is carried out to determine the availability ofnutrients to crops, samples i.e., the furrow slices, are 6” long.Why should a PVC bucket be used?An iron bucket may have rust, which might contaminate the sample. Presenceof iron would skew the results of the organic carbon test as we shall see later.Jute or nylon bags which may have been used to store fertilizer etc. must notbe used too.PVC (or any other plastic) would not contaminate the soil. Besides, they are easyto clean.1-4 Collection and Preparation of soil samples
  • 11. Collecting soil samples Remove a wedge-shaped lump of soil from the cleared sampling location and discard it. The resulting pit should be about 6 inches (15 cm) deep. From the two larger surfaces of the pit, remove a half inch thick slice of soil — called the furrow-slice. Thus, from each sampling location on the field, two furrow- slices are obtained. Carry these in a PVC bucket.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-5
  • 12. Collecting soil samplesAfter collection — what now?You now have a bucketful of furrow-slices. However, it would be time-consumingto test all the soil in each of the furrow-slices separately and then average theresults. Ideally, you would want to test a relatively small sample of soil which,nevertheless, represented the soil present in the entire field.This is achieved by thoroughly mixing the soil. Further, to simplify the labexperiments, the samples are ground and sieved... We’ll discuss this issue in thenext section...1-6 Collection and Preparation of soil samples
  • 13. Collecting soil samples After all the samples are collected, they could be taken directly to the laboratory — if one is close enough. Else, the samples may be prepared on location itself, and a composite soil sample may be sent for testing. The samples are now air-dried in the shade.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-7
  • 14. Drying the soil samplesWhy are the samples dried?In dried soil, any reversible chemical reactions that usually take place in it arein equilibrium.However, drying does change the chemical constituents of soils. Ferrous ironis oxidised to ferric iron, exchangeable potassium content increases or decreasesdepending upon the soil and hydrogen ion activity changes to some extent.Therefore, concentration of ferrous iron (if required) should be determined witha field-moist soil sample. Also, concentration of exchangeable potassium andsoil pH may also be determined without drying the sample.Dried soil is easier to grind.For reasons mentioned earlier, metallic apparatus must not be used for grindingas particles might break off and contaminate the soil.Therefore, a wooden mortar and pestle must be used.1-8 Collection and Preparation of soil samples
  • 15. Grinding the soil samples Spread a clean polythene sheet on the ground and place a wooden mortar on it. Transfer the dried soil samples to the mortar. With a wooden pestle, grind the soil to break down any aggregates. After grinding, transfer the soil to the polythene sheet and spread evenly across the surface.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-9
  • 16. Mixing Why is mixing important? After all, we just ground the samples — that should have mixed everything quite well. Mixing is necessary to ensure that the composite soil sample (all the soil samples taken from different areas in the field) represents the field’s soil composition as closely as possible even in small quantities. For example, to determine the amount of phosphorus, as little as 2.5 g of soil is used in the experiment. You would have collected nearly 3 kg of soil from the field of which only about 500g of soil is sent to the soil-testing centre. Therefore, unless properly mixed, it is likely that soil from some parts of the field might not reach the testing centre. Yes, during grinding, mixing does take place — but it is random and might not be enough. Besides, like the collection stage, the mixing stage described here is to establish a process that minimises chances of statistical error.1-10 Collection and Preparation of soil samples
  • 17. Mixing Lift one end of the sheet and fold it till the soil collects in the centre. Repeat the process with the diagonally opposite corner as shown in the picture... and then with the other two corners... This will cause the soil to collect in the centre of the sheet. This process is called Mixing and must be repeated 5 times. Cone the soil and flatten the top.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-11
  • 18. Partitioning the soil sample Partitioning? At this stage, you have about 3kg of a composite soil sample. This would be a rather unwieldy package to transport to the testing labs. Besides, the lab will need only about 300g of soil for all the tests. Here is where the purpose behind the monotonous mixing process becomes apparent. Because the sample is mixed, statistically, the average chemical composition of the field is represented by surprisingly small amounts of soil — as little as a few grams!So, you don’t need to send in all the soil you’ve collected painstakingly — youcould send in 500g which is relatively easier to transport and store.There is a catch though — selecting the final soil sample must also be done atrandom . This is fulfilled by the next Stage — Partitioning.This involves halving the mass of the soil sample in successive stages till it isabout 500g. At each stage, a random portion of soil is selected.The method described here is one of many that may be used to quarter thesoil sample. There are others, such as : The Riffle Technique and The PaperQuartering Technique.However, the method described needs no extra apparatus and is very easy.Hence its use in this manual.1-12 Collection and Preparation of soil samples
  • 19. Partitioning the soil sample Divide the soil into 4 equal portions, as shown. Discard any two diagonally opposite portions. This process is called Partitioning.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-13
  • 20. Partitioning the soil sample1-14 Collection and Preparation of soil samples
  • 21. Partitioning the soil sample Continue partitioning the sample till about 500g of soil remains. The amount of soil retained depends upon the number of experiments that the Soil Chemist intends to conduct. 500 g is enough if all tests are to be carried out. Transfer all the soil to a sieve.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-15
  • 22. Sieving the soil sampleWhat mesh size is to be used?A fine sieve (80 mesh) is used for determination of oxidisableorganic carbon and the elements i.e., Nitrogen, Phosphorus andPotassium.A coarse sieve (20 mesh) is used for determination of soil pHand salinity.The entire volume of the partitioned sample should pass throughthe sieve. Soil aggregates that are too large to be sieved shouldbe ground in a mortar and sieved again.1-16 Collection and Preparation of soil samples
  • 23. Sieving the soil sample Sieve the soil. Preparation is complete. The soil particles have been ground, mixed, partitioned and sieved. Before the soil is transported to the lab, it must be stored in polythene bags.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-17
  • 24. Packing the soil sample1-18 Collection and Preparation of soil samples
  • 25. Packing the soil sample Seal the open end of the bag with thread. Label the bag. The information required by the laboratory for testing is shown in the Information Sheet (see Page 9-28) The samples are now ready for transport. The picture shows 3 polythene bags — these are samples from adjoining fields all headed to the testing centre.Collection Grinding Partitioning Storage Drying Mixing SievingCollection and Preparation of soil samples 1-19
  • 26. 1-20 Collection and Preparation of soil samples
  • 27. Soil testing - Determination of soil pHpH electrodes dipped into a soil-water suspension for pH measurement 1-21
  • 28. Introduction A bit about pH... pH is the quantitative measure of acidity or alkalinity of liquid solutions. A solution with a pH value less than 7 is considered acidic and a solution with a pH more than 7 is considered alkaline. pH 7 is considered neutral. Soil pH between 6 and 8 is safe for most crops. If the tested sample has a pH value outside this “safe range”, steps must be taken to artificially correct the problem. The acidity of a solution is directly proportional to its hydrogen ion concentration. The term pH is derived from p representing the German word potenz, ‘power’, + H, the symbol for hydrogen. pH meters are extremely sensitive instruments. They consist of one (or two) glass electrodes connected to a digital display. The pH of a solution is displayed when the electrodes of the meter are dipped in it. Soil water suspension : A suspension, as opposed to a solution, is a heterogeneous mixture, i.e., its constituents may be separated by physical means. The mixture of soil in water is therefore a suspension, not a solution. Apparatus and reagents required Buffer tablets of pH 4.0 and 7.0, a top loading balance, a 100mL beaker, a wash bottle, a glass rod and a pH meter Determination of Lime Requirement : An acidic soil is treated with Lime to increase its pH. Recommendation of liming is also done after a pH test. The difference being the addition of an extra ingredient to the soil. Take 5g of soil instead of 20g as shown here. Add 5mL of distilled water and then add 10mL of SMP Extractant Buffer. Proceed with the pH exactly as shown in the following pages. When you obtain the pH value, refer to the Lime Recommendation Table on page 9-28.1-22 Determination of soil pH
  • 29. Preparing a soil suspension Weigh out 20g of soil. Transfer the soil to a 100mL beaker. Add 50ml of distilled water. This creates a soil-water suspension. The soil : water ratio for conducting this test should be 1 : 1.25 Stir the suspension occasionally for about half an hour or shake in a shaker for 5 minutes.Preparing the soil suspension Measuring the pH of the sample Calibrating the pH meterDetermination of soil pH 1-23
  • 30. Using the pH meter... Calibration? Why is it necessary? Think about this — how does the meter know a solution’s pH? It doesn’t. It’s just programmed to display different pH values depending upon the voltage across its electrodes. The electrodes, though, are sensitive to a whole lot of other things — like temperature for instance. So, even though a change in room temperature will not change the pH of a solution, it will cause the electrodes to report the pH incorrectly. And this is true of any measuring instrument. We calibrate by measuring a known amount and then re-programming the meter to display that amount — this is sometimes as simple as pushing a switch. In this experiment, we calibrate the meter with 2 buffer solutions — with pH values of 7.0 and 4.0. See page 1-26 for a description of buffer solutions. First, we dip the electrodes in the pH 7.0 buffer. While we were conducting the experiment, the meter read 7.2. This was because it was set to measure correctly at a slightly lower room temperature. So, the adjustment knob was turned till the display read 7.0. Between readings, wash the electrodes with distilled water and wipe them dry with a piece of clean tissue paper. Repeat the process with a buffer solution of pH 4.0. The volumetric flask in the third picture contains the pH buffer solution. The meter might need a few minutes to “warm up”. The time varies from model to model and you should check the literature that came with your meter. Generally, “warming up” takes a few minutes. Also, it takes a few seconds for the display to stabilise after you’ve dipped the electrodes in a solution. So, wait a while before noting down a pH reading.1-24 Determination of soil pH
  • 31. Calibration Calibrate the pH meter with any two known buffer solutions. Just prior to taking any readings, stir the soil-water suspension with a glass rod. Dip the electrodes of the pH meter into the suspension and take a reading.Preparing the soil suspension Measuring the pH of the sample Calibrating the pH meterDetermination of soil pH 1-25
  • 32. A buffer story A bit about Buffer Solutions We know about pH and how it describes the acidity or alkalinity of a solution. Now, why is a solution acidic? Or alkaline? Modern definitions of acidity refer to the ability of the compounds in a solution to accept or release electrons — the Lewis Concept. But historically, an acid was a compound that, in solution, could release hydrogen ions into the solution, and a base was a compound which could accept hydrogen ions. Since HCl dissociates into H+ and Cl- ions, in solution, it is an acid. There are situations when we want the pH of a solution to remain constant — irrespective of change in the concentrations of its acidic or alkaline constituents. This is done by adding an acid-base pair to the solution that acts as a reservoir, or buffer. What this reservoir does is suppress or increase the dissociation of other compounds depending upon the pH of the solution. A commonly used buffer solution is the NH4Cl - NH4OH pair. These are readily soluble chemicals and keep each other’s dissociated concentrations in check — in line with the solubility product principle. The NH4Cl - NH4OH pair is an alkaline buffer and maintains the pH of the solution at around 8.5. You can read more about Buffer Solutions in books on Physical Chemistry. A thin “chemical film” is deposited on the electrodes each time a pH measurement is taken. Unless removed, this film causes the electrodes to report inaccurate values. Therefore, between readings, wash the electrodes of the pH meter with a stream of distilled water and then wipe them dry with tissue paper. When not in use keep the electrodes dipped in distilled water.1-26 Determination of soil pH
  • 33. Meter readings... The pH of the sample tested is 7.79. The display on most pH meters takes about a minute to stabilise.Preparing the soil suspension Measuring the pH of the sample Calibrating the pH meterDetermination of soil pH 1-27
  • 34. 1-28 Determination of soil pH
  • 35. Soil Testing - Determination of salinityConductivity readings are taken from the supernatant liquid.. 1-29
  • 36. Introduction A bit about salinity... The determination of the quantity of water-soluble salts is of special importance for arid, semi-arid as well as coastal areas. It helps in taking reclamation measures as well as in the selection of crops which differ in their tolerance to salts. While we could measure the concentrations of the salts by chemical analysis, it would be time-consuming, expensive — and entirely unnecessary. That’s because, we don’t need to identify all the salts lurking about — we’re only interested in the water-soluble ones. The concentration of all of these salts taken together is what matters to plants. So, we take a more practical approach to measure soil salinity — we add distilled water into the soil and stir it till the soluble salts get dissolved. Then, we measure the electrical conductivity of the water. And how does that tell us anything about salinity? Indirectly, it does — because in solution, ions are the carriers of electric charge and therefore, the electrical conductivity of a solution is directly proportional to its soluble salt concentration. The conductivity of a soil sample is measured with the help of a conductivity meter and is expressed in mmhos/cm. or, in SI units, in dS/m. You don’t even need to calculate the concentrations for the purposes of recommending fertilizers. The recommendation is based upon the conductivity measurement itself. ( See the recommendation tables). Most soil testing labs mention “Electrical Conductivity” or just “E.C.” in their reports. Apparatus and reagents required 0.01N KCl solution, a 100mL beaker and a conductivity meter.Using a conductivity meter...An electrical conductivity meter is very similar to a pH meter. It also consistsof an electrode connected to a digital display. Measurements are made by dippingthe electrode in the solution being tested.The precautions to be observed while using this instrument are the same asthose with a pH meter (see page 1-24 ).1-30 Determination of salinity
  • 37. Calibrating the conductivity meter This is a typical Conductivity Meter. Like the pH meter, its electrode must be kept immersed in distilled water when not in use. Calibrate the meter. This is done with distilled water and a 0.1N Potassium Chloride solution. Distilled water should display 100 in the digital panel. Then, dip the electrode in a 0.1N KCl solution.Calibration of the Conductivity meter Measuring conductivity Supernatant LiquidDetermination of salinity 1-31
  • 38. A bit about supernatant liquid What is Supernatant liquid? The liquid that floats above a suspension after it has been allowed to stand for a while is termed “Supernatant”. When measuring conductivity, the conductivity cell should remain in the Supernatant liquid and not touch the soil below as shown. So, why are we measuring the conductivity of the supernatant liquid? After all, during the pH experiment we had specified that the soil shouldbe in suspension while the reading was being taken.The supernatant liquid is a solution. The salts present in the soil dissolve in waterand dissociate into ions, which are charged particles. The concentration of solublesalts in the soil may, therefore, be calculated from the conductivity of thesupernatant liquid.Soil - water ratio? Why is that important?Soil to water ratio should be 1:2. The ratio influences the amount of salts in theextract. Some laboratories use different ratios while conducting this test. Eitherway, the ratio must (and is) always mentioned in a soil analysis report.1-32 Determination of salinity
  • 39. Conductivity readings... Adjust the cell constant knob till the meter displays 14.1 m.mhos/cm. The soil water suspension from the pH experiment is allowed to stand till a clear supernatant liquid is obtained. After setting the range switch to maximum, the electrode is dipped in the supernatant liquid. Reduce the range setting on the meter one at a time till the most appropriate setting is found. In this case, the conductance of the soil sample is 1.20 m.mhos/cm.Calibration of the Conductivity meter Measuring conductivity Supernatant LiquidDetermination of salinity 1-33
  • 40. 1-34 Determination of salinity
  • 41. Soil Testing - Determination of available organic CarbonDiphenylamine indicator being added drop by drop 1-35
  • 42. Introduction A bit about Oxidisable organic carbon... Decomposed plants and microbial residues are the constituents of organic matter. The percentage of oxidisable organic matter can be determined by multiplying its percentage of organic carbon by 1.724. Oxidisable organic carbon consists of partly decomposed residues of plants, animals and microorganisms. This constitutes most of the usable carbon present in the soil. The other forms of carbon which are present, but not useful as a source of nutrients, include inorganic carbon (such as carbonates), elemental carbon (such as coal and graphite) and completely decomposed organic carbon. For areas known to have very low organic matter content take 2g of soil in the conical flask, for peat soils, take 0.05g and for areas known to have about 1-2% of organic carbon content, take 0.5g of soil. Apparatus and reagents required 1N potassium dichromate solution, 0.5N ferrous ammonium sulphate solution, diphenylamine indicator, concentrated sulphuric acid and 85% orthophosphoric acid solution. 500mL conical flask, titration setup (50mL burette, chromyl chloride solution to clean the burette and titration stand) 10mL bulb-type pipette, chemical balance, 1000mL volumetric flask and two watch glasses. Why are two conical flasks used? This experiment is based upon the Walkley and Black method according to which soil is digested with chromic acid resulting in the oxidation of its organic content. The excess chromic acid is determined by titration with a standard ferrous ammonium sulphate solution. After titration, in the case of the soil sample, the amount of titrant consumed is obtained. The amount of titrant consumed in a blank titration (without soil) could be calculated stoichiometrically. But this would require accurate weighing of all the reagents involved in the reaction. Therefore, it is much simpler to perform a blank titration to obtain the required figures i.e. the volume of ferrous iron solution consumed.1-36 Determination of oxidisable organic carbon
  • 43. Oxidising the carbon in the soil sample Take two 500mL conical flasks. Add 1g of soil to one of the flasks. Add 10mL of K2Cr2O7 to each of the flasks with a pipette.Oxidizing the carbon in the soil Titration of the soil sample suspension Blank Titration CalculationsDetermination of oxidisable organic carbon 1-37
  • 44. Precautions... Concentrated sulphuric acid is a very corrosive chemical. It fumes in contact with moisture. Observe the following precautions when using sulphuric acid : The acid must be poured into the beaker along a glass rod or along its inner walls. DO NOT use a pipette to measure out the acid - if any of the acid gets into your mouth, there might not be enough of it left to talk about the experience! This step should ideally be carried out in an Exhaust Cabinet because the fumes are extremely corrosive as well. Don’t try to smell the fumes however tempting it might seem! What happens during the half hour? The oxidisable organic carbon in soil is oxidised by potassium dichromate 3C + 2K2Cr2O7 + 8H2SO4 = 3CO2 + 8H2O + 2K2SO4 + 2Cr2 (SO4)3 Potassium dichromate is converted to potassium sulphate and chromium sulphate. Cr6+ is reduced to Cr3+. The colour of the oxidised form of chromium(Cr6+) is yellow (or orange) and that of it’s reduced form (Cr 3+ ) is green. The volume of K2Cr2O7 solution added to the soil should be large enough so that only a small fraction of it is reduced - which is indicated by yellow (or orange) c o l o u r o f t h e r e a c t i o n m e d i u m a f t e r c o m p l e t i o n o f ox i d a t i o n . This occurs over a period of 30 minutes. Because sulphuric acid fumes, reagents might get deposited on the watch glass. Therefore, when adding water, if you see flecks of chemicals deposited on the watch glass, rinse them and allow the water to drip into the conical flasks.1-38 Determination of oxidisable organic carbon
  • 45. Oxidising the carbon in the soil sample With a measuring cylinder, add 20 mL. of concentrated sulphuric acid to each of the flasks. Cover the flasks with watch-glasses and allow them to stand for about half an hour. Then, add about 200 mL of distilled water to each of the flasks.Oxidizing the carbon in the soil Titration of the soil sample suspension Blank Titration CalculationsDetermination of oxidisable organic carbon 1-39
  • 46. Titration A bit about titration... Titration is a process by which the amount of an oxidisable or reducible substance in solution is determined by measuring the volume of a standard reagent required to react with it. The burette used must be cleaned with chromyl chloride prior to titration. Dirty burettes are the most common cause of errors. Carry out the blank titration first. This will give you a general idea about the volume of titrant, i.e., Ferrous ammonium sulphate that will be consumed. With this value in mind, the titration of the soil sample usually takes less time. Observe the colours that the solution assumes during the process. In the first phase, the solution is a dark burgundy. After a while, it turns violet. This indicates, approximately, the mid point of the titration. Local action is also observed at this point. The remainder of the titration needs to be carried out carefully, i.e., by agitating the contents of the flask after every 2 drops. The end-point is indicated by a sudden change of colour of the solution to viridian, or dark green. During the titration of the soil sample, all the indicative colours are more cloudy than those observed during the blank titration. This is due to suspended soil particles. Why is Orthophosphoric acid used? Orthophosphoric acid, H3PO4, is added so that the colour change at end point is clearly defined. Diphenylamine should be added just prior to titration. This is to avoid the potassium dichromate from oxidising the indicator instead of the organic content of the soil sample being tested. During titration, a small amount of diphenylamine is oxidised, however, the error is negligible.1-40 Determination of oxidisable organic carbon
  • 47. Blank Titration Add 10mL of orthophosphoric acid to each of the flasks. Just prior to titration, add about 10 drops of Diphenylamine indicator to the flask. The solution turns a dark burgundy. The blank titration is done first. Titration is done with a 0.5N Ferrous ammonium sulphate solution.Oxidizing the carbon in the soil Titration of the soil sample suspension Blank Titration CalculationsDetermination of oxidisable organic carbon 1-41
  • 48. Local action... And a few calculations What is local action? Local action is a phenomenon observed midway during titration. At this stage, even though the titration is not complete, a faint, localised “end point” may be observed in the solution where the titrant drops fall. To observe local action during this experiment allow a drop of titrant, i.e., Ferrous ammonium sulphate, to drop on the solution without agitating the flask as is normally done during titration.The solution in the immediate vicinity of the drop turns green momentarily. A few Calculations... The CD-ROM has a Chemical calculator that does all the work for you but since we’ve set out to understand the science behind Agricultural Biotechnology, let’s dive headfirst into yet another bout with theory — and learn a bit about Stoichiometry. The Appendix contains an article that explains why you need to add and divide all these numbers... The percentage of oxidisable organic carbon (%OC) in the soil sample is given by % O.C. = [VK x (1– VS/VB) x SK x 0.3] / W where Vk = Volume of Potassium dichromate solution VS = Volume of Ferrous iron solution consumed in titration with soil VB = Volume of Ferrous iron solution consumed in blank titration Sk = Strength of Potassium dichromate solution W = Weight of soil1-42 Determination of oxidisable organic carbon
  • 49. Indicative colours during titration... Midway through the titration, the colour of the solution turns to clear purple. At this stage, local action may be observed. End point is indicated by a sudden change of colour to viridian, or dark green. Titrate the soil sample as well. Notice that all the indicative colours with the soil sample are cloudy. The picture shows the titrated soil sample suspension at end point.Oxidizing the carbon in the soil Titration of the soil sample suspension Blank Titration CalculationsDetermination of oxidisable organic carbon 1-43
  • 50. 1-44 Determination of oxidisable organic carbon
  • 51. Soil Testing - Determination of available NitrogenAmmonia bubbling up the neck of a Kjeldahl flask 1-45
  • 52. A bit about the Experiment A bit about the Experiment Plants generally take up nitrogen as nitrate under aerobic conditions. In anaerobic situations, some crops, such as rice, can take up nitrogen as ammonium ions. Most of the nitrogen present in soil is present in complex compounds. This is considered as a potential reserve source and, as such, it may be measured to assess the nitrogen-supplying capacity of the soil. Soil testing centres do not usually conduct a separate test for determining the quantity of available nitrogen in a soil sample brought to them for testing. Instead, they calculate this quantity directly from the quantity of oxidisable organic carbon. And how exactly is that possible? The ratio of the amount of oxidisable organic carbon is proportional to the amount of nitrogen in a given area. The ratio is unique to each region. These ratios have been tabulated. In Nimpith, where VIB is located, the ratio is 1 : 5. With this value, we need only perform the organic carbon test to determine the quatities of both nitrogen and oxidisable organic carbon. Apparatus and reagents required Boric acid solution, Mixed indicator, 0.32% potassium permanganate solution, 2.5% sodium hydroxide solution, liquid paraffin. Kjeldahl flask(s), distillation setup, titration setup, 250mL conical flask and a few glass beads. Glass beads and liquid paraffin These are used to reduce frothing and the formation of bubbles in the solution when the flask is heated. The bubbles may carry soil into the delivery tube and deposit them in the conical flask connected to the other end of the tube. The presence of soil makes it hard to detect the end point when we titrate the contents of the conical flask. More on this topic later...1-46 Determination of Available Nitrogen
  • 53. Extracting the Nitrogen as Ammonia Take 20g of soil in a Kjeldahl Flask. Add 20mL of distilled water. Coat a few glass beads in liquid paraffin and put them in the flask. Extracting the Nitrogen as Ammonia Calculations Titration of the condensateDetermination of Available Nitrogen 1-47
  • 54. Extracting the Nitrogen as Ammonia A bit about Kjeldahl and the flask he invented... A Danish chemist called J.G.C.T. Kjeldahl came up with the brilliant idea of estimating nitrogen concentrations in organic substances by distilling it out as ammonia — which can be easily assayed. For boiling the organic substance, he made a round-bottomed glass flask with a long neck. A special heat-resistant glass is used which does not crack when heated to high temperatures and is expposed to relatively cooler liquids at the same time. The entire assembly is called a Kjeldahl setup or unit and the flask also bears its inventor’s name.1-48 Determination of Available Nitrogen
  • 55. Extracting the Nitrogen as Ammonia Then add 100mL each of 0.32% potassium permanganate and 2.5% sodium hydroxide solutions. Heat the flask to about 80oC on an electric heater. Ammonia is evolved. The gas escapes into the delivery tube attached to the Kjeldahl flask. Extracting the Nitrogen as Ammonia Calculations Titration of the condensateDetermination of Available Nitrogen 1-49
  • 56. Extracting the Nitrogen as Ammonia Why do we use mixed indicator? In this test the pH changes at two distinct points. The first is when the ammonia is absorbed by the boric acid and the solution changes from bright pink to green. The second occurs during the titration of the solution with sulphuric acid. The solution then changes back to pink. These changes occur at different pH values and a single indicator is not sufficient since indicators exhibit a colour shift only in a small pH range. Thus, we need two indicators which will show us both these changes. Hence a mixed indicator — which is a mixture of Methyl Red, Bromocresol green and Ethanol — is used in this experiment.1-50 Determination of Available Nitrogen
  • 57. Titration of the condensate The evolved gases condense and are collected in a conical flask containing Boric Acid solution and Mixed Indicator. The Ammonia is absorbed by the acid — indicated by a change in colour of the solution to green. Continue boiling the contents of the Kjeldahl flask till about 100mL of distillate is collected. Titrate the distillate with 0.02N sulphuric acid. Extracting the Nitrogen as Ammonia Calculations Titration of the condensateDetermination of Available Nitrogen 1-51
  • 58. Titration of the condensate My end point is brown! You did not pour in enough paraffin. Or, perhaps, you didnt use enough glass beads. These ingredients are added to reduce the surface tension of the solution in the Kjeldahl flasks. This greatly reduces bubble formation... The bubbles often carry small amounts of soil and deposit it in the conical flask. This “muddies” the indicative colours during titration and hence the end point appears brownish... A few calculations Substitute the observed volume, V, of sulphuric acid consumed in the following equation to calculate the amount of available nitrogen (in kg per hectare) of the soil sample — V X 31.36 kg/Ha1-52 Determination of Available Nitrogen
  • 59. Titration of the condensate... and Calculations Local action is observed distinctly during titration. End-point is indicated by a change in colour from green to a brownish-pink. Note the value of sulphuric acid consumed. Carry out a blank titration — with the contents of the conical flask corresponding to the Kjeldahl flask without soil. Extracting the Nitrogen as Ammonia Calculations Titration of the condensateDetermination of Available Nitrogen 1-53
  • 60. Titration of the condensate... and Calculations1-54 Determination of Available Nitrogen
  • 61. Soil Testing - Determination of available PotassiumFlame view - the orange-red colour indicates the presence of potassium 1-55
  • 62. A bit about Potassium A bit about potassium In soil, potassium may be found in four compound forms - Water soluble, Exchangeable, Fixed and Lattice-bound. Of these, plants are interested only in the first two since they cannot assimilate potassium when it is present in the last two types of compounds. Potassium is the most abundant meta-cation in plant cells. Oddly though, soil humus furnishes very little potassium during decomposition. Also, it occurs in plants only as a mobile, soluble ion, K+, rather than as an integral part of any specific compound - but, it is known to affect important aspects of a plants life such as cell division, formation of carbohydrates, translocation of sugars and resistance of the plant to certain diseases. Over 60 enzyme actions are known to require potassium for activation. Which is why it forms the “K” part of the NPK trio - the three major important elements that plants require for proper growth. Incidentally, the “K” comes from “Kalium” which is what potassium used to be called. And a bit about the experiment In the next experiment, when testing for phosphorus, we will learn about a technique called curve fitting. This experiment also uses the same principle but the curve fitting itself is done electronically by the machine itself. So what machine are we talking about? It’s called a Flame Photometer. It consists of two parts — the gas compressor (that’s the first picture on the right) and the Aspirator/Measurement unit (the second picture). The principle on which this gizmo operates is that every element, when burnt in a flame, emits energy in a set series of wavelengths. Simply put, each element burns with a different colour. Further, the intensity of colour is directly proportional to the concentration of the element. So, by measuring the intensity of colour of flame aspirated with the sample, and comparing it with a known set of colour intensities, the photometer c a n d e t e r m i n e t h e c o n c e n t ra t i o n o f p o t a s s i u m i n t h e s a m p l e . The gas compressor regulates the flow of LPG to the Photometer. The gas burns with a nearly colourless (or faint blue) flame. The soil sample extract is then sucked into the flame in minute quantites. This causes the water to vapourise instantly and the compounds in it burn in the flame. The colour of the flame changes depending upon the elements present in the extract. This is detected by electronic sensors which calculate the intensity of the colour. Potassium burns with an orange-yellow flame. Apparatus and reagents list is on page 1-601-56 Determination of available Potassium
  • 63. Calibrating the photometer Set the Compressor to supply gas at a pressure of 0.45kg/cm2. Ignite the flame and then calibrate the photometer with solutions whose potassium concentrations are known. The calibration must be done with 4 standard solutions.Calibrating the Flame Photometer Measuring the concentration Extracting the Potassium from the sample CalculationsDetermination of available Potassium 1-57
  • 64. Calibrating a Flame PhotometerEnter “Calibration” mode We’re working with pretty The smart meter nowusing the control panel. high concentrations of realises that it needs toThe buttons you have to Potassium here. plot a Standard Curve. Sopress will vary for different you need to tell it howmodels. Some meters are designed many standard samples for micro-analysis — like you’re going to use to plotUsually, you’ll see a the one here. In our case, the curve. We’ll use 4numbered list of options. we need to tell it to expect samples. Most meters areIn this case, we press “5” Potassium in high good enough to accuratelyon the numeric keypad to concentrations. “fit a curve” with thisenter Calibration mode. number of samples.It now wants to know the Sampling time! Aspirate The flame colour changesconcentrations, in ppm, of each of the stock solutions immediately to a brightthe standard solutions one by one — in the order orange-yellow. Thewe’re going to use. Here, in which you keyed them change in intensity of thewe use solutions with 100, into the meter. We typed colour will be barely75, 50 and 25 ppm in the concentrations in noticable to the nakedconcentrations. descending order (100,75, eye. The meter however, 50,25), so, we’ll have to can distinguish each a s p i ra t e t h e 1 0 0 p p m colour precisely. solution first.1-58 Determination of available Potassium
  • 65. Calibrating a Flame PhotometerAfter each sample is The flame becomes After aspirating distilledaspirated, the meter colourless when distilled water, repeat with the nextdemands a “washing” with water is aspirated. It might Standard sample. Notedistilled water — just like also be a faint blue colour. that the display in thethe E.C. meter and the pH The picture here has been picture reads STD4, orm e t e r. N o t i c e h o w deliberately modified to Standard Sample No. 4.different measuring exaggerate the colour ofapparatus all have the the flame — so that you This was taken when we’dsame operating principles. can easily compare the already aspirated the firstIt’s really quite simple — flame colours with and three samples. Now, weno magic, just science! without the sample. aspirate the 4th sample.Between each sample, the Calibration is over. Now, Shubham, it seems, hasmeter will ask you to the meter is ready to test no question to ask on thisaspirate distilled water. the soil sample extract - topic and wants to get onAfter all the 4 samples are we don’t know the with the experiment!aspirated, the meter concentration of Potassiumsounds a satisfied beep in this. The meter willand tells you happily that analyse the colour of thecalibration is over. flame, plot its density on the standard curve that it’s drawn for itself and tell us t h e c o n c e n t ra t i o n o f Potassium. Calibrating the Flame Photometer Measuring the concentration Extracting the Potassium from the sample Calculations Determination of available Potassium 1-59
  • 66. Extracting the potassium from the soil sample Ammonium Acetate? Why is this used? Like in the Phosphorus experiment, we need to find a way to extract the Exchangeable Potassium from the soil sample. That’s what Ammonium acetate is used for. The ratio of soil : Ammonium acetate should be 1:5. That is, if you used 5.0g of soil, take 25mL of ammonium acetate. Ammonium acetate dissociates to yield ammonium ions CH3COONH4- CH3COO- + NH4+ The NH4+ ions replace the K+ ions, held on exchange sites of soil colloids. As a result, K+ ions are released into solution. Perfect for our purpose! The chemical equation above has two arrows pointing in both directions. This indicates a reversible reaction — i.e. one that occurs simultaneously in both directions. However, each reversible reaction has an equilibrium point at which the rates of both the forward and backward reactions remain constant. Chemistry can be a really exciting subject! You can find out more about reversible equations in any textbook on Physical Chemistry. See the Appendix for a list. Apparatus and reagents required 1N ammonium acetate solution of pH 7.0, 1000ppm potassium solution of pH 7.0. 10mL pipette, 150mL conical flask with a rubber stopper, 50mL volumetric flask, 100mL measuring cylinder, a funnel, Whatman no. 42 filter paper and a flame photometer. This experiment is shown using a direct read-out electronic flame photmeter.1-60 Determination of available Potassium
  • 67. Extracting the potassium from the soil sample Take 5g of soil in a 150mL conical flask. Add 25mL of 1N Ammonium Acetate. The pH of the solution should be 7.0. Cork the flask and agitate its contents for about 30 minutes. This can be done with a mechanical shaker.Calibrating the Flame Photometer Measuring the concentration Extracting the Potassium from the sample CalculationsDetermination of available Potassium 1-61
  • 68. Extracting the potassium from the soil sample Whatman No. 42... Whatman No. 1... Who is this man called What? It’s a brand name. “Whatman”, the company, makes filter paper — and a lot of other paper products used in Chemical analysis. The paper is graded according to its relative porosity. Hence, No. 1, No. 42 etc. An interesting feature of these papers is that they are “ashless”. This means that you can burn them and they do not leave behind a residue. This property is useful in a lot of experiments — such as gravimetric analysis, in which the filter paper is burned after it is used for filtration thereby leaving all the precipitate behind for weighing. Neat! Also, whoever started up the company was probably called “Whatman”... If that helps at all....1-62 Determination of available Potassium
  • 69. Extracting the potassium from the soil sample Filter the suspension through Whatman No. 42 paper. The filtrate is used for determining Potassium concentration. Transfer the filtrate to beakers for use with the Flame Photometer. Aspirate the filtrate (the soil sample extract).Calibrating the Flame Photometer Measuring the concentration Extracting the Potassium from the sample CalculationsDetermination of available Potassium 1-63
  • 70. Calculations... The results and some calculations.... Easy as pie! The smart Flame Photometer tells you the concentration of Potassium in the extract after politely asking you to wait for a while. In our case, the concentration of Potassium was 22.3. The K 2 O content of the soil is calculated using this formula - K20 (in kg/hectare)= [ 2 X CK ppm X Ve ] / Ws where CK ppm = Concentration of the Potassium in ppm obtained from the Photometer Ve = Volume of Ammonium Acetate used Ws = Weight of soil taken, in grams You can use Chemi-Calc, the calculator on the CD-ROM, to do the calculations. Or, if you want to show off a bit as well (like the Photometer did), use this trick Multiply the CK ppm amount by 10! Remember that the ratio of soil to extractant used should be 1 : 5. Which means that if you followed the steps, you would have taken 5g of soil and 25mL of Ammonium acetate. Those values then cancel out to give 5 in the numerator part of the equation. Multiply that by 2(also in the numerator) and you get [ CK ppm X 10] But beware, the trick works ONLY if you measured out the Ammonium acetate and the soil carefully to at least a couple of decimal places. So 25.01mL and 5.02g of soil is fine. But 25.5 mL and 5.2g of soil means your experiment will be approximately OK but you cannot show off with the calculation trick! The formula gives you the amount of K2O present in the soil (in kg per hectare). To find the amount of Potassium multiply the result from the calculation above by 0.83. However, this is not necessary for recommendation since we are interested in the K2O amount — Why? Because that’s the compound that Fertilizers Companies refer to! They aren’t very smart, are they?1-64 Determination of available Potassium
  • 71. Measuring the concentration of Potassium in the soil sample Presence of potassium is indicated if the flame changes to a yellow-orange colour. The minute colour differences between the colours emitted by different elements are not distinguishable by the naked eye. The flame view is provided primarily for adjusting the stability of the flame and verifying that the nozzles of the aspirator are not contaminated by residues from previous experiments. The concentration of Potassium, in ppm, is displayed on the screen after a few seconds.Most soil testing labs are not equipped with direct-display Photometers like theone used here. Older equipment requires the user to plot a Standard Curvemanually on Graph Paper. If such equipment is used, the process described inSection 7 (the procedure used to determine the amount of Phosphorus) isapplicable here as well.Calibrating the Flame Photometer Measuring the concentration Extracting the Potassium from the sample CalculationsDetermination of available Potassium 1-65
  • 72. 1-66 Determination of available Potassium
  • 73. Soil Testing - Determination of available PhosphorusThe blue colour indicates presence of phosphorus 1-67
  • 74. Preparing a Standard Curve A bit about available Phosphorus... Phosphorus occurs in soil in both organic and inorganic forms, most of which is not easily available to plants. A portion of the total Phosphorus is absorbed by plants during their growth in the form of H2PO4= . This is what we refer to as available phosphorus. What is a Standard Curve and what is it’s use? Simply put, it is a graphical means of determining unknowns that are variables of a linear equation. The catch is, that this is an equation of the form y = n x, where n might vary randomly as x varies. So how is that linear, you may ask. It is, approximately, because if we define n as n + e, then we find that e is a very small positive or negative number. The easier method to solve the problem, is to plot, on graph paper, a few (x,y) pairs and draw ONE line — the Standard Curve — connecting as many points as possible. If e was a relatively large number then we would have no option but to resort to esoteric mathematical tools like regression analysis because then the equation would cease to be approximately linear. But because e is a small number, we would find that most points are either on — or very close to — the straight line drawn and points are scattered almost equally on either side of the line. Then, to find the value of y for any given x (or vice versa) all you need to do is find the corresponding point on the line. Thus, we’ve found the solution to a linear equation by graphical means. Let’s call it the Graph Technique. Sounds difficult? It isn’t. As an exercise, try plotting the following value pairs on a sheet of graph paper (x,y) = (0 , 0) , (1.1 , 1) , (4.9 , 5) , ( 6.2 , 6) , (7.3 , 7) and (11 , 11). Draw a line that joins the points - you will find that the points are scattered to either side of the straight line joining (0 , 0) and (11 , 11). Using this line, find out the value of y when x is 8. You get y = 8. Now, the actual value of y might not be 8 exactly, but the graph shows that it would be pretty close to 8, if not exactly 8. In most cases, as in our present experiment, the small error is negligible. Apparatus and reagents required Olsens extractant or Bray and Kurtz No. 1 extractant, Standard 100ppm phosphate solution, ammonium molybdate reagent (containing antimony potassium tartrate and ascorbic acid), 2,4-dinitrophenol, P-free charcoal. Eight 25mL volumetric flasks, 10mL graduated pipette, 10mL measuring cylinder, a funnel, graph paper, Whatman No. 42 filter paper and a colorimeter.1-68 Determination of available Phosphorus
  • 75. Preparing a Standard Curve Take eight 25 mL volumetric flasks and add 1mL, 2mL, 3mL, 4mL, 5mL and 10mL of 2 ppm Phosphate solution to six of them. Leave two flasks blank. Add 5mL of a 2ppm Standard Phosphate solution to one of the empty flasks. Add 5mL of Olsens Reagent to the same flask.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-69
  • 76. Preparing a Standard Curve A step-by-step description of the process... First we need to plot a Standard Curve. In this test, it is plotted to determine, approximately, the relationship between the intensity of colour and the needle deflection of the Colorimeter (the reading on the scale) — the assumption being that the relationship would be linear. It is linear, by the way... Which makes this an ideal candidate for using the Graph Technique described on page no. 1-68. Now, we need a few stock solutions of Phosphorus to plot the Standard Curve. We take 6 such solutions. Then, we need to find out how much the Colorimeter would read when the solutions are placed in it. At this stage two problems crop up — (1) The Phosphorus in the soil is present primarily as a Phosphate of Calcium, Iron and Aluminium — which are all colourless. So the Phosphorus needs to be extracted AND (2) the new compound, in solution, must have a colour whose intensity varies linearly with respect to its concentration. The extraction part is done by adding either Olsen’s extractant which is a 0.5M NaHCO3 solution or by Bray and Kurtz No.1 Extractant. Ammonium molybdate reagent or "Reagent B" (which is a cocktail of Ammonium Molybdate, Tartarate and ascorbic acid) is used to obtain a heteropoly complex called phosphomolybdic acid, which is reduced, partially, by the ascorbic to give a blue coloured solution. The amount of the complex produced is directly proportional to the Phosphorus concentration. Problem solved! The two flasks to which we did NOT add any stock solution are used to simplify a technical hitch (see page 1-78) when Olsens extractant is used. The Flask with Olsens reagent described in the facing page will be used to carry out a mini-titration to determine the amount of acid required to lower the solutions pH to 3. The other flask will be used as a "blank". This lets us know if any of the chemicals we are using contain Phosphorus as an impurity. Shubham will be lurking on these pages to elaborate as we discuss the steps of the experiment!1-70 Determination of available Phosphorus
  • 77. Preparing a Standard Curve Add two drops of 2,4-dinitrophenol indicator to the flask. The solution turns yellow. Then, with a graduated pipette or dropper, add 2.5M Sulphuric acid to the flask till the yellow colour is discharged. This indicates that the pH of the solution is 3. Note down the volume of acid consumed. In our test, 0.4mL of acid was required to lower the pH when 5mL of Olsens reagent was added. This flask is not needed any more and may be removed from the work area. This leaves 7 flasks — 6 with standard phosphate solutions and one empty flask for the blank test.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-71
  • 78. Preparing a Standard Curve More on the pH value The value obtained in the previous step — 0.4mL of acid — pertained to 5mL of Olsens extractant. So, if we use, say, 50mL of the reagent, we need to add 4mL of 2.5M sulphuric acid to adjust the pH of the solution. Since weve standardised the procedure (always using 5mL of filtrate and so on) the value obtained earlier — 0.4mL — is used throughout.1-72 Determination of available Phosphorus
  • 79. Preparing a Standard Curve We now have seven flasks left. To each of the flasks, add 5mL of Olsens reagent. Add exactly 0.4mL of 2.5M Sulphuric Acid to each of the flasks to adjust the pH of the solution to 3. Add approximately 10mL of distilled water to each of the flasks. Then, add 4mL of Reagent B — the Ammonium Molybdate reagent mixture - to each of the flasks. The picture shows the reagent being pipetted into the flask containing 10mL of the Standard Phosphate solution.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-73
  • 80. Using a colorimeter Using the Colorimeter Colorimeters are usually analogue — measurements are indicated by the deflection of a needle over a semicircular scale — and they look very ancient in the laboratory, surrounded by digital equipment. However, they are very precise instruments as well! Colorimeters have a light-proof slot where the sample to be tested is inserted. If the sample is opaque, a full-scale deflection is observed, whereas a transparent sample does not cause any deflection of the needle. Calibration The zero and full scale deflections are set by “measuring” a sample of distilled water and a black, opaque cylinder (that comes as a standard accessory with the meter and is designed specifically for this purpose.) Turn the adjustment knob to set the needle to the zero when calibrating with distilled water. With the opaque cylinder in the metering slot, turn the adjustment knob so that the needle deflects all the way and stops in front of the “infinity” mark. More on the Standard Curve... After you’ve measured the optical densities of all the six solutions, plot them on a sheet of graph paper. The concentrations of Phosphorus in each of the flasks, in parts per million, go on the x-axis, while the corresponding optical densities go on the y-axis. Draw a straight line that connects most of the dots. That’s your Standard Curve! By the way, you might be wondering why it’s called the Standard Curve when it is a straight line. Well, it would be a curve if the equation were not linear. For instance, if the relationship between y and x were quadratic ( y = nx2 + c) then the graph would be a curve. Besides, (and this might sound silly) mathematically, a straight line is also a curve!1-74 Determination of available Phosphorus
  • 81. Preparing a Standard Curve Add distilled water to each of the flasks till the volume of solution in them is exactly 25mL The 25mL value is to be maintained for all solutions. The value determines the concentration of the phosphate solution. Remember that ppm is a measure of concentration. Allow the flasks to stand for 10 minutes. The solutions assume a blue tinge. Measure the optical densities of all the solutions using a colorimeter. The blank sample should register a "zero" deflection while the sample with 10mL of the standard phosphate solution should register the highest optical density.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-75
  • 82. Phosphorus free or not... On to the extraction We have the Standard Curve and now we proceed to extracting the Phosphorus from the soil sample. This is the part that you will be doing more often since a Standard Curve only needs to be prepared once a day. Remember to note down the volume of acid used to adjust the pH of Olsens Reagent. In our case, the volume is 0.4mL. Olsen’s Method This method is used to extract Phosphorus in soils with pH above 6. The Bray and Kurtz Method is employed to extract Phosphorus from soils with pH below 6. The reagent used for extraction, in this case is a solution of 0.03 N Ammonium fluoride in 0.025 N HCl. Olsens reagent is added at 1 : 20 ratio to the soil. Thus, when 2.5g of soil are taken for extraction, 50mL of Olsens Reagent is to be used. Bray and Kurtz Reagent is added at a 1 : 10 ratio. Usually you will find yourself using Olsen’s Method more often. The steps followed for employing both the methods are identical except for the ratio mentioned above. Preparation of the Standard Curve should also be done with the same reagent used for extraction.1-76 Determination of available Phosphorus
  • 83. Extracting Phosphorus from the sample Take 2.5g of soil in a 150mL conical flask. Add about 0.5g of Phosphorus-free charcoal to the conical flask. Prior pH tests on the soil sample indicate that its pH is 7.2. Hence, Olsens Reagent is used as an extractant. Add 50mL of Olsens Reagent to the flask.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-77
  • 84. Extracting Phosphorus from the sample 2,4-dinitrophenol and ascorbic acid 2,4-dinitrophenol is used as an indicator. The test is to be carried out at a pH of 3.0. Therefore, we add 2.5M sulphuric acid, drop by drop, till the yellow colour of the 2,4-dinitrophenol is discharged indicating that the pH of the solution is exactly 3.0. This causes a conflict with Reagent B — the ammonium molybdate mixed with antimony potassium tartarate and ascorbic acid. Ascorbic acid cannot be used if we use 2,4-dinitrophenol. Some laboratories use stannous chloride in conjunction with pure ammonium molybdate. The problem with this method is that the blue complex formed is very unstable and the colour disappears in a few minutes. In a soil testing centre, where you could be testing 100 samples everyday, you cannot use Stannous Chloride. So we have a bit of problem! The solution is to carry out a kind of “mini-titration” to determine exactly how much 2.5M sulphuric acid is required to bring the pH of the solution down to 3.0. We do this by adding 5mL of Olsen’s Extractant to a 10mL volumetric flask and then adding two drops of 2,4-dinitrophenol. The solution assumes a yellow colour. Then, we add 2.5M Sulphuric acid to the flask drop by drop through a graduated pipette, till the yellow colour is discharged. This gives us the amount of acid required to correct the pH for 5mL of extractant. Note that one does not need to lower the pH when using Bray and Kurtz Extractant. After addition of this reagent, we directly add 4mL of Reagent B and then top up with distilled water to 20mL.1-78 Determination of available Phosphorus
  • 85. Extracting Phosphorus from the sample Agitate the contents of the flasks for half an hour in a mechanical shaker. Filter the suspension through Whatman No. 42 filter paper. Then, transfer exactly 5mL of the filtrate to a 25mL volumetric flask. Add 0.4 mL of 2.5M Sulphuric acid.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-79
  • 86. The Standard Curve 0.16 0.14 0.12 0.10 Optical Density 0.08 0.06 0.04 0.02 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Concentration of Phosphorus (in ppm) The Standard Curve...again The relation between concentration and optical density is linear. And like we know, it is plotted by measuring the optical densities of solutions with known strengths — marked red. After you’ve completed the experiment, you have an optical density reading of a solution with an unknown concentration of phosphorus - marked blue. The x-axis value gives you the concentration, in ppm, of phosphorus in the soil sample. A Standard Curve is usually prepared daily in the soil testing lab. Calculations Substitute the ppm concentration of phosphorus obtained into the following equation to obtain the availibility per hectare. P2O5 (kg/hectare) = Vc x Ve x cppm x 2 x 2.2 /Vf x W where cppm = ppm concentration obtained from the standard curve Vc = Volume of the coloured solution in mL Ve = Volume of extractant taken for extraction of P from soil in mL Vf = Volume of filtrate taken for colour development in mL W = Weight of soil taken in grams1-80 Determination of available Phosphorus
  • 87. Measuring the concentration of Phosphorus Add 4mL of ammonium molybdate reagent. The solution turns blue within a few minutes. Add distilled water to the flask till the volume of solution in it is exactly 25mL. The solution turns blue. After 10 minutes, measure the optical density of the solution in a Colorimeter. Plot the value on the standard curve you obtained earlier. This is marked in blue on the Standard Curve on the facing page.Preparing a Standard Curve Measuring the concentration of Phosphorus Extracting Phosphorus from the soil sample CalculationsDetermination of available Phosphorus 1-81
  • 88. 1-82 Determination of available Phosphorus
  • 89. Soil Testing - Determination of Gypsum requirementAt end-point, the solution changes from a wine-red to a greenish-blue 1-83
  • 90. A bit about the experiment A bit about the experiment Alkali soils contain large amounts of sodium. This element has huge ions. Soil aeration and permeability are two conditions that are adversely affected by the monstrous Sodium atoms hogging space.To improve the situation, Sodium cations (Cations are atoms that have lost anelectron and, hence, are positively charged) are displaced by Calcium cations.The Sodium is then leached away by percolating water.Gypsum — CaSO4.2H20 — is used as a source of Calcium. The following pagesdescribe the test to determine how much Gypsum needs to be applied to a field. Apparatus and reagents required Two 250mL conical flasks, a 150mL conical flask, a funnel, Whatman No. 42 filter paper, titration setup. Saturated gypsum solution, ammonium hydroxide-ammonium chloride buffer solution, EBT indicator, EDTA solution.1-84 Determination of Gypsum requirement
  • 91. Adding Gypsum to the soil sample Ta ke t w o 2 5 0 m L c o n i c a l f l a s k s To one of the flasks, add 5g of soil. Leave the other flask empty. It will be used to carry out a blank test. To the flask containing soil, add 100mL of a saturated gypsum solution.Determination of Gypsum requirement 1-85
  • 92. Adding Gypsum to the soil sample Remember this... Add 5mL of the SAME gypsum solution that you added to the soil sample. The experiment is to determine how much Gypsum in the 100mL solution is adsorbed by the soil sample. The amount of gypsum adsorbed directly affects the strength of the solution. We compare the strengths of the two solutions by titrating equal volumes — 5mL of filtrate and 5mL of the original solution. The difference in the volume of EDTA consumed in both the titrations is used to determine the Gypsum requirement of the field where the sample was taken.1-86 Determination of Gypsum requirement
  • 93. Adding Gypsum to the soil sample To the other flask, add 5mL of the same saturated gypsum solution. Agitate the soil suspension in a mechanical shaker for 5 minutes. Filter the suspension through Whatman No. 42 filter paper.Determination of Gypsum requirement 1-87
  • 94. Why add a buffer? Why do we add the buffer solution? If iron is present in large amounts in the soil sample, it will interfere with the titration and skew the results. The ammonium hydroxide-ammonium chloride buffer stabilises the pH of the solution at 10. This is highly alkaline and causes any Iron present in the solution to precipitate as a hydroxide — thereby ensuring that the titration gives us the required results. Other elements such as copper and nickel are also present in mostsoils but not in amounts enough to cause significant errors in the experiment.1-88 Determination of Gypsum requirement
  • 95. Titration of the filtrate Transfer 5mL of the filtrate to a 150mL conical flask. Then, add 1mL of ammonium chloride- ammonium hydroxide buffer solution and 25mL of distilled water to both the flasks - the flask for the blank test and the flask with 5mL of filtrate. Add 2-3 drops of EBT indicator. The solutions assume a wine-red colour.Determination of Gypsum requirement 1-89
  • 96. A few calculations A sight for sore eyes... One of the most interesting aspects of Analytical Chemistry are the colours one sees. Fiery reds, moody blues and shocking pinks... Theyre all on display. Titration is a case in point. Even veteran chemists are sometimes distracted by the beautiful display of a solution magically changing colour. This particular titration is perhaps the most interesting of the ones described in this book. Wine Red to blue... The introductory page to this section contains a full page picture of the solution at end-point. A few calculations... The amount of Gypsum that the soil sample requires is calculated by substituting values into the following formula - Gypsum requirement (tons/Ha) = SEDTA(Vb-Vs) X 688.68 where Vs = Volume of the EDTA required for titration of the soil filtrate Vb = Volume of the EDTA required for blank titration SEDTA = Strength (in N) of the EDTA solution1-90 Determination of Gypsum requirement
  • 97. Titrating the filtrate and the blank Titrate with EDTA. End Point is indicated by a change in colour to blue-green. Note down the value of EDTA consumed. Titrate the blank next. Note down the volume of EDTA consumed.Determination of Gypsum requirement 1-91
  • 98. 1-92 Determination of Gypsum requirement
  • 99. Soil Testing - Reagent preparationExtraction of phosphorus using Olsen’s Reagent 1-93
  • 100. Take all the usual precautions while using chemicals — The bibliograpy at the end of this manual lists quite a few books on lab-practice. Read one of them. Or, ask a lab technician to show you the precautions. Observing a technician at work is not recommended — lab technicians sometimes skip safety measures while they work. Ask them to explain the procedures to you while theyre not at work.1-94 Reagent preparation
  • 101. We’ve followed a graphical method of explaining the procedure for preparing labreagents. Most of the reagents are prepared simply by adding a weighed amountof solid (crystalline) reagent to distilled water and mixing the two. A 1L volumetricflask is commonly used.In cases where the reagent may not be soluble in distilled water at roomtemperature, a little acid is also added to the mixture. The preparation procedure is described in a step-by-step format. The capacity of the container is mentioned to its left. Make sure you use a flask/beaker of the right capacity. 1L The colour that the solution assumes at the END is shown in a circle below the container capacity. A white circle indicates a colourless solution. If the flask needs to be heated, it is indicated by an orange “flame” at the bottom. A step that involves corrosive chemicals is indicated by a red circle. A step that involves transfer of the solution to another container midway through the preparation (for, say, filtration) is indicated by an arrow p o i n t i n g o u t wa r d f r o m t h e c o n t a i n e r. Step 1 Step 2 Add 20mL of sulphuric acid Filter the solution and store in a reagent bottleReagent preparation 1-95
  • 102. 1N Potassium Dichromate 1L Take 49.04g of potassium dichromate and put it in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1L1-96 Reagent preparation
  • 103. 0.5N Ferrous Ammonium Sulphate 1L Take 196.1g of ferrous ammonium sulphate in the flask Add 700mL of distilled water Add about 20mL of concentrated sulphuric acid. DO NOT use a pipette — use a measuring cylinder Agitate the contents by shaking the flask gently till the salt dissolves. After the salt is dissolved, add more distilled water till the volume of the solution is 1LReagent preparation 1-97
  • 104. SMP Buffer solution (pH 7.5) 1L 1.8g of p-nitrophenol 2g of Calcium acetate 2.5mL of triethanolamine 3g of Potassium Chromate 53g Calcium Chloride Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salts dissolve After the salt is dissolved, add more distilled water till the volume of the solution is 1L Adjust the pH of the solution to 7.5 with dilute Sodium Hydroxide.1-98 Reagent preparation
  • 105. Diphenylamine Indicator 250mL Take 500mg of Diphenylamine indicator powder in the beaker Add 20mL of distilled water Add about 100mL of concentrated sulphuric acid. DO NOT use a pipette — use a measuring cylinder Agitate the contents by shaking the flask gently till the indicator dissolves After the salt is dissolved, store it in a brown reagent bottleReagent preparation 1-99
  • 106. 0.32% Potassium Dichromate 1L Take 3.2g of potassium dichromate in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1L1-100 Reagent preparation
  • 107. 2.5% Sodium Hydroxide 1-74 1L Take 25g of sodium hydroxide in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1LReagent preparation 1-101
  • 108. [Methyl Red + Bromocresol Green + Ethanol] MixedIndicator 250mL Take 0.07g of Methyl Red indicator in the beaker Add 0.1g of Bromocresol Green Add 100mL of Ethanol Swirl the contents of the beaker to mix them well After the contents are mixed thoroughly, store the indicator in a brown reagent bottle1-102 Reagent preparation
  • 109. Boric Acid + Mixed Indicator 1L Take 20g of boric acid in the flask Add 700mL of distilled water Warm up to 80oC Add 200mL of Ethanol Add 20mL Mixed Indicator Add 0.05N Sodium Hydroxide till the solution turns reddish-purple After the salt is dissolved, add more distilled water till the volume of the solution is 1LReagent preparation 1-103
  • 110. Olsen’s Extractant 1L Take 42g of sodium bicarbonate in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves. Adjust the pH to 8.5 by adding either dilute HCl or dilute NaOH solution After the salt is dissolved, add more distilled water till the volume of the solution is 1L1-104 Reagent preparation
  • 111. 2,4-dinitrophenol Indicator 250mL Take 500mg of 2,4-dinitrophenol indicator powder in the beaker Add distilled water while stirring the solution to make a supersaturated solution Filter or decant the solution Store the filtrate in a reagent bottleReagent preparation 1-105
  • 112. Standard 100ppm Phosphate solution 1L Take 0.4392g of potassium orthophosphate in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1L1-106 Reagent preparation
  • 113. 2.5M Sulphuric acid 1L Take 800mL of distilled water Add 140mL of sulphuric acid Agitate the contents by shaking the flask gently After mixing the acid, add more distilled water till the volume of the solution is 1LReagent preparation 1-107
  • 114. [Ammonium Molybdate + Tartarate + Ascorbic acid] ReagentB 500mL Take 12g ammonium molybdate (AR grade) in the beaker Add 250mL of distilled water 2L Ta k e 0 . 2 9 0 8 g o f antimony potassium tartarate reagent in the beaker Add 100mL of distilled water. Take 1L of 2.5M sulphuric acid in the flask. Mix throughly and add water till the volume of the solution is 2L. 250mL -200mL Take 1.056g ascorbic acid in the beaker1-108 Reagent preparation
  • 115. 1N Ammonium Acetate of pH 7.01L Take 77.08g of ammonium acetate in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1L Adjust the pH of the solution to 7 by adding a little dilute acid/alkaliReagent preparation 1-109
  • 116. Standard Potassium Solution (1000ppm) 1L Take 1.908g of potassium chloride in the flask Add 800mL of distilled water Agitate the contents by shaking the flask gently till the salt dissolves After the salt is dissolved, add more distilled water till the volume of the solution is 1L1-110 Reagent preparation
  • 117. Abiotic — AnaerobicAbiotic Factor in the Environment : Nonliving forms (physical and chemical) inthe environment that influence the environmental processesAbsorptive : A substance that can absorb and hold waterAseptic Condition : A situation where there is no microorganismAcetylene : An organic gas with the chemical formula C2H2Acetylene Reduction Assay (ARA) : The nitrogen fixing enzyme, Nitrogenase, inaddition to the reduction of nitrogen to form ammonia, can also reduce acetyleneto form ethylene. The rate of this reaction is measured and extrapolated asnitrogenase activity. This assay is called as ARA.Acid Soil : A soil with a pH value less than 7. Usually applied to surface layeror root zone, but may be used to characterize any horizon or sample.Adaptability : Power of an organism to make itself fit in altered environmentalconditionAdhesion : Physical attachment between two different bodies.Adventitious Root : The roots of a mature embryophyta developed from partsother than primary root initialAeration Device : A device by which air can pass through a systemAerobic : An organism, a system or a reaction that requires oxygen for itsoperationAgar-agar : A polysaccharide derived from seaweeds (Red algae) used assolidifying agent in culture mediumAir-dry : The state of dryness (of soil) at equilibrium with the moisture contentin the surrounding atmosphere.The actual moisture content will depend uponthe relative humidity and the temperature of the surrounding atmosphere.Alkaline Soil : Any soil that has pH greater than 7. Usually applied to surfacelayer or root zone but may be used to characterize any horizon or a sample.Ambient Temperature : Temperature of the surrounding environment.Amylase : An enzyme that breaks starch into glucoseAnaerobic : An organism, a system or a reaction that does not require oxygenfor its operation7-2 Glossary of Terms
  • 118. Annuli — BiofertilizerAnnuli : Plural of annulus: ring-like segments of the cylindrical body of annelids,like earthwormAnterior Region : Proximal part of an animal bodyAntibacterial : Any chemical or physical agent or any phenomenon that inhibitbacterial activityAntifungal Compound : Compound that inhibits the growth of fungus or destroyit.Aquatic Environment : Combination of all the physical, chemical and biologicalfactors in an water body, which influence living formsArid Region : Dry and bare region where the sunlight is of high intensityAshbys Medium : A medium for the culture of Azotobacter, the constituents ofwhich was developed by AshbyAutoclave : A device for wet sterilizationAuxins : A group of bioactive compounds having promoting effect on plant growththrough cell division, elongation and differentiationAvailable Forms of Plant Nutrients : The form of plant nutrients that are solublein water and can be absorbed by the plant rootAvailable Nutrient : That portion of any essential element or compound in thesoil that can be absorbed readily and assimilated by growing plants.Available Forms Of Plant Nutrients : Simple, inorganic and water-soluble formsof plant nutrients that can readily be absorbed by the plant root systemBacteria : Prokaryotic (without true nucleus) unicellular microorganism havingcell wall and spore producing capability; present in all parts of biosphereBeneficial Microorganism : The microorganisms that improve the soil quality bytheir biological actionBiochemical Process : Chemical reactions taking place within the cell or externalto the cell but always with the help of enzymes produced by the cellsBiodegradable : The substances that can be decomposed by the microbial activityBiodegradation : Decomposition of complex biological macromolecules of organicbodies into simpler forms by bacterial activityBiofertilizer : Preparation containing living or latent cells of microorganisms,Glossary of Terms 7-3
  • 119. Biological — CFUwhich, when applied to soil, increase their number in soil and improves soilfertility through their biological actionBiologically Degradable Organic Waste : Organic waste that can be decomposedby microbial activityBiomass : Total amount of living and nonliving organic contentBiotic Factor in Environment : Living forms that influence environmental processesBlue Green Algae (BGA) : The BGA are prokaryotic microorganisms living onwater or moist soil. They are photosynthetic and some of them are nitrogen-fixers.Broth : Liquid culture containing bacterial cellsBuffer : It is a solution containing an acid and a base, or a salt that tends tomaintain a constant H+ concentration. A buffer tablet with a specific value (as4.0, 7.0, 9.2) when dissolved in 100 ml distilled water, gives a buffer solutionof that specific pH value.C-4 plants : Normally, the first stable product in photosynthesis is phosphoglycericaldehyde, a three-carbon compound (C-3) plant). In some plants, the first stablecompound is a 4-carbon compound — malic acid. These plants are called C-4plants. The photosynthetic efficiency of these plants is comparatively highCalcareous Soil : Soil containing sufficient calcium carbonate (often with magnesiumcarbonate) to effervesce visibly when treated with cold 0.1N HCl.Carbofuran : A pesticideCarbohydrate : Organic compounds that are composed of carbon, hydrogen andoxygen, where the ratio of hydrogen and oxygen is 2:1, as in waterCarbohydrate : A class of biological macromolecule constituted of carbon, hydrogenand oxygen, where the ration of hydrogen to oxygen is 2:1 as in water moleculeCarrier : A finely granular solid phase that can hold and carry microbial cells insufficient quantity giving suitable environment to themCellulase : The enzyme that breaks cellulose, the major component of plant cellwallCFU : Colony forming unit. Spreading of bacterial suspension on plate distributethe individual cells separately on the surface. On incubation, each cell developsone colony. But a few cells may remain in clumps. Such clumps, comprising oftwo or few cells, will develop individual colonies. Thus enumeration of microbialculture is made in terms of the number of CFU rather than the number of cells.7-4 Glossary of Terms
  • 120. Chemical Energy — CultureChemical Energy : Energy remaining latent within high-energy chemical compounds( as in carbohydrate ); to be derived after breakdown by chemical means(respiration)Chemical Environment : Chemical factors like concentrations of different chemicalcompounds in a systemChemical nitrogen Fertilizer : Nitrogenous compounds that are applied in fieldas nitrogen source of crop plant e.g. Urea, Di-ammonium phosphateChitinase : An enzyme that degradess chitin, a component of plant cell wallCirculatory System : Combination of organs in animal body responsible for thecirculation of metabolites, excretory products etc.Cocoon : The fertilized eggs of earthwormsCoelom : The body cavity of lower animalsColonization : Increase in number of individuals in a particular area throughpropagationColonization of Microorganism : Development of a microbial community in aparticular area through growth (cell division)Colour : A land may show two different colours, viz., light colour and dark colour.Soil samples from these two-coloured lands should be collected separately andanalysed as they vary in their properties.Combined Nitrogen : Compounds containing nitrogen ( ammonia, nitrite, nitrate)Composite Soil Sample : Soil samples collected from a number of sites of a soilunit are thoroughly mixed to represent the properties of the soil unit. The mixedsample is termed composite soil sample.Compost : Organic residues, or a mixture of organic residues and soil that havebeen piled, moistened and allowed to undergo biological decomposition.Contaminants : Any undesired living form in microbial cultureContamination : Appearance of any undesired living form in a pure living population(as in microbial culture)Cross-fertilisation : Union of male and female sex cells of two different organismsCulture : Growing living cells or tissue in artificial or semi-natural nutrient mediumGlossary of Terms 7-5
  • 121. Culture Medium — Endogeic EarthwormsCulture Medium : A solution consisting of all the required food substances toculture living cells or tissueCumulative Effect : Combined effects of different factorsCurling : A disease of plant where the leaves or fronds are curled inwardly oroutwardly, caused by bacteria, fungus or viruses.Cytokinin : A group of bioactive compounds having promoting effect on plantcell division, specially division of cytoplasm.Decomposing Microorganisms : The microorganisms that are involved in thedegradation of complex biological macromolecules into the simpler formsDecomposition : Degradation of complex biological macromolecules present inorganic bodies into smaller and simpler forms by bacterial activity.Defence Mechanism : A measure to protect an organism from pathogenic agents.Digestive System : A system in animal body responsible for intake, digestionand absorption of foodDilution Plating Method : A method of serial dilution of microbial culture, soil,food etc., plating the dilutes and consequent incubation to enumerate the numberof viable cells or colony forming units of microorganisms, general or specific.Diptera : An insect group comprising of insects with single pair of wingsDominance : PrevalenceDorsal Side : The backsideDoubling Time : The time required to double its content through multiplicationDull Colour : Colour not so brightEC : Electric ConductivityEffluent : Liquid industrial waste of sewageElectrical Conductivity of Soil (EC) : The measurement of electrical conductivityis based on the principle that ions are the carriers of electricity. The electricalconductivity of a solution increases with increase in soluble salt concentration.The electrical conductivity of a soil is measured with the help of conductivitymeter and is expressed in mmhos/cm. (now in dS/m). Thus the measurementof EC helps us to know the concentration of water-soluble salts in the soil.Endogeic Earthworms : The earthworms that obtain their food from the deep7-6 Glossary of Terms
  • 122. Endomycorrhiza — Essential Plant Nutrientslayer of substrate / soilEndomycorrhiza : Mycorrhiza where the fungus remain within the root tissueEnumeration : Counting of a particular object in relation to space of a particularevent in relation to timeEnvironment : The combination of all the physical, chemical and biological agentssurrounding an organism that has significant effect on the organism.Environmental Factors : All the physical, chemical and biological components ofthe environment, which influence the ecosystem including the living forms.Enzyme : A protenacious macromolecule of biological origin and of specialstructural and functional organisation that regulate a specific biological reactionEnzyme, Chitinase : See chitinaseEnzyme, Nitrogenase : See nitrogenaseEnzyme, Amylase : See amylaseEnzyme, Cellulase : See cellulaseEnzyme, Lipase : See lipaseEnzyme, Protease : See proteaseEpigeic Earthworms : The earthworms that obtain their food from the surfaceof substrate /soilOesophagus : The proximal part of the digestive canal beyond the pharynxEssential Plant Nutrients : Nutrient means something that serves as food ornourishment. There are 16 chemical elements known to be essential for thegrowth of the higher plants. These are C, H, O (absorbed from air and water),N, P, K, Ca, Mg, S (macronutrients absorbed from the soil), Mn, Zn, Cu, Cl, B,Mo (micronutrients absorbed from the soil). In the absence of these elementsplants develop deficiency symptoms character tic of the deficient element. Hencethe name essential plant nutrients.Glossary of Terms 7-7
  • 123. Ethylene — Gibberrellic AcidEthylene : An organic gas with the chemical formula C2H4, can be produced bythe reduction of acetylene.Evaporation : Loss of water in form of vapourExcretory System : The system in animal body responsible for the release ofharmful products produced as by-products during metabolismFermenter : A system within which optimum condition for the growth andmetabolism of microorganism is established artificiallyFertility Status of Soil : It is the nutrient status of the soil. Soil fertility meansthe ability or the capacity of the soil to provide the essential plant nutrients informs readily available to the plant.Fertilization : Union of gametes of two opposite sexesFertilizer Gap : Difference between the amount of fertilizer applied in field andthe amount that is really absorbed by the cropFertilizer Requirement : The quantity of certain plant nutrient elements needed,in addition to the amount supplied by the soil, to increase plant growth to adesignated optimum.Fertilizers : Natural or artificial substance containing the chemical elements thatimprove the growth and productiveness of plants. Fertilizers enhance the naturalfertility or replace the chemical elements taken from the soil by previous crops.Modern chemical fertilizers include one or more of the three elements mostimportant in plant nutrition — N, P, and K.Flora : The total set of plant community in a given ecosystemFossil : Any article that proves the presence of particular living forms in remotepastFossil Fuel : The fuel derived from plants and animals of remote past (coal andpetroleum)Free-living microorganism : The microorganisms that can live freely in environmentwithout any biological relationship with othersFungi : Eukaryotic (having true nucleus) microorganism having a plant-like cellwall but no chlorophyll; capable of spore production, heterotropicFungicide : A chemical agent that inhibit or eliminate fungal infection in plantsor seeds.GA : Gibberellic acid, a plant hormone7-8 Glossary of Terms
  • 124. Genital pore — Host specificityGenital Pore : A pore through which sex cells are released in malesGibberellins : A group of compounds having promoting effect on plant growth,especially during germination and differentiation of roots.Gizzard : A strong muscular organ in digestive canal responsible for the macerationof ingested foodGregarious : Living in a flock or companyGreen Manure : Some highly nitrogen-containing plants that are cultivated andmixed with the soil by tilling. The plant nutrients are released after decompositionGrinding : It is the process of breaking or crushing the soil samples by woodenmortar, roller, motorized grinder into soil aggregates taking care that primarysand particles are not crushed.Growth Promoting Substances : Natural or synthetic substances that promotethe growth and development of plantsGypsum Requirement : The quantity of gypsum or its equivalent required toreduce the exchangeable sodium percentage of a given increment of soil to anacceptable level.Hard And Sticky Soil : The soil where the particles remain tightly adhered togive the soil hard nature when dry and sticky nature when wetHardpan : A hardened soil layer, in the lower A or in the B-horizon, caused bycementation of soil particles with organic matter or with materials such as silica,sesquioxides, or calcium carbonate. The hardness does not change appreciablywith changes in moisture content and pieces of the hard layer do not slake inwater. A horizon is the surface horizon of a mineral soil having maximum organicmatter accumulation, maximum biological activity and / or eluviations of materialssuch as iron and aluminium oxides and silicate clays. B horizon is the onebeneath the A’ that is characterised by one or more of the following (i) concentrationof silicate clays, iron and aluminium oxides and humus alone or in combination(ii) a blocky structure and (iii) coatings of iron and aluminium oxides that givedarker, stronger or redder colour.Heavy Soil : Soil with high proportion of clayHeterotropic : The living forms that cannot synthesise their own food and dependupon other autotropic organisms for their food requirement.Host : An organism that harbours other parasitic or symbiotic organismHost Specificity : Specificity of pathogenic of symbiotic microorganism to recogniseand infect a suitable hostGlossary of Terms 7-9
  • 125. Hyaline— Light soil Hyaline : Transparent IBA : Indole Butyric Acid — a plant hormone Incubation : Keeping any biological system in its optimum condition of operation. Incubator : A device where the optimum condition is maintained for the operation of a biological system Ingestion of Food : Uptake of food in the digestive canal Inoculation : Addition of starter culture (inoculum) to the medium or soil to initiate the growth Inoculum : A little amount of microorganism that is added to the culture media or soil to initiate the growth Inorganic Phosphate : Inorganic compounds containing phosphate (viz. ammonium phosphate, potassium dihydrogen phosphate etc.) Intestine : The distal part of the digestive canal Invertebrate : An animal having no backbone Jensens Medium : A medium for the culture of Azotobacter, the constituents of which was developed by Jensen. Laminar Flow Cabinet (LFC) : A device where microbiological operations are done in aseptic condition Leaf Litter : Leaves lying about Leghaemoglobulin : A proteinacious iron compound present in the root nodules of leguminous plants Lepidoptera : An insect group comprising of insect with two pair of wings, wings fold upwards when at rest Light Soil : Sandy soil7-10 Glossary of Terms
  • 126. Lime (Calcium) Requirement — Microbial InoculantsLime (Calcium) Requirement : The amount of agricultural limestone ( a sedimentaryrock composed of over 50% calcium carbonate) required per acre to a soil depthof 6 inches (15cm) or on about 910,000kg of soil to raise the pH of the soil toa desired value under field conditions.Limiting Factor : The critical factor that limits the activity of a system in spiteof abundance of other regulating factorsLipase : An enzyme that breaks fats into fatty acid and glycerolLoamy Soil : Soil with equal parts of sand and clayLog-phase : Rapid growth phase of living formsMaceration : Softening and grinding of the ingested foodMacronutrient : A chemical element necessary in large amounts (usually 50 ppmin the plant) for the growth of plants. See also Essential Plant Nutrients.Management Unit : It is the unit of soil representing a distinct managementpractice that the previous crop has received, e.g., if a portion of the previouslycropped land was irrigated and the other portion was not irrigated, the land hastwo soil units viz., irrigated and non-irrigated land. Separate soil samples areto be collected and analysed to represent each distinct soil unit.Medium, Ashbys : See Ashbys MediumMedium, Culture : See Culture MediumMedium, Jensens : See Jensens MediumMedium, P.K. : See P.K. MediumMedium, Slant : See SlantMedium, YEM : See YEM MediumMineralisation : A process of breakdown of complex biological macromoleculesinto simplest chemical forms that are available to the plantMetabolism : All the biochemical reactions occurring within the living cellMetabolites : All the intermediate compounds and end products of metabolismMicrobial Inoculants : Liquid or carrier based preparation of living or latent cellsof microorganismsGlossary of Terms 7-11
  • 127. Micro-habitat — Nitrogen Fixing Micro-organismsMicro-habitat : Isolated habitat (a region where an organism dwells) with verysmall area where all the environmental conditions suitable for the growth andactivity of the organism is establishedMicronutrient : A chemical element necessary in only extremely small amounts(less than 50 ppm in the plant ) for the growth of the plants. See also EssentialPlant Nutrients.Microorganism : Living forms that can be identified under microscope, veryminute in size, visible by naked eye when in groups or colony and cannot beidentifiedMicroorganisms : The living beings that are too small to be identified by nakedeye; can be observed clearly and identified by microscopeMineralisation : Conversion of complex organic compounds to simple inorganicformsMixing (soil) : The methodical process of mixing soil for lab analysis. This processis part of a set of techniques to obtain a composite soil sample that representsthe entire plot of land.Moist Soil : Soil with water near 100% of its water holding capacityMonotelic : The organism breeding only once in whole lifeMycorrhiza : A symbiotic association between fungus and root system of higherplants where both are benefitedNAA : Naphthalene Acetic Acid — a plant hormoneNematode : Soil born, very minute, cylindrical, invertebrate animalNiche : Position of an organism in relation to habitat, food habit, role in theecosystem, etc.Nitrogen-Fixation : Conversion of atmospheric nitrogen into ammoniaNitrogenase : The enzyme that catalyses reduction of nitrogen into ammonia innitrogen fixing microorganismsNitrogen-fixing Microorganisms : The microorganisms that can convert atmosphericnitrogen into ammonia7-12 Glossary of Terms
  • 128. Nocturnal — PK MediumNocturnal : An animal that feeds at nightNodulation Efficiency : Efficiency of rhizobial culture to infect the root of specificleguminous plant and to develop nodule.Nodule : Tumorous growth in a part of root of leguminous plant caused by noduleforming, nitrogen-fixing bacteria — RhizobiumNon-palatable : Not tasteful and non-desirableNutrients : Elements required for the nutrient of an organismOptimum Condition : The condition most suitable for the operation of a particularactivityOrganic Carbon : The carbon in the form of organic compoundOrganic Carbon (%) : The organic carbon that is estimated involves mostly thepartly decomposed organic carbon and rarely the completely decomposed ones.It excludes 90 to 95% of less active organic matters that are not beneficial forplant growth (charcoal, graphite).Organic Humus : Decomposed organic matter in soilOrganic Matter : Materials derived from the dead bodies of living formsOrganic Phosphate : Organic compounds containing phosphate (viz. nucleic acids,phospholipids etc.)Organic Waste : Waste material derived from plant or animal source, e.g. straw,paper, cow dung, fruit and vegetable waste etc.Ova : Plural of ovum — the female sex cellOvary : The female reproductive gland where female sex cells, ova, are producedOviduct : A tubular system through which the ovum is transported from ovaryto female poreOxygenic Photosynthesis : The photosynthetic process where the hydrogenrequired for the reduction of carbon dioxide is derived from water molecule andoxygen is released as a by-productP.K. Medium : Pikovskias medium for the culture of phosphate solubilisingmicroorganismsGlossary of Terms 7-13
  • 129. Partitioning — Photosynthesis Partitioning : The process of dividing the thoroughly mixed soil samples into four parts (quarters), also called quartering technique. IN this multi-step process, the soil sample is divided into 4 equal portions and two portions are selected for analysis. The selected portions are mixed and partitioned repeatedly till about 500g of soil is left. Pesticide : Chemical agent that inhibit or eliminate pest manifestation in plants or seeds. pH : pH is the quantitative measure of acidity or alkalinity of liquid solutions. A solution with a pH value less than 7 is considered acidic and a solution with a pH more than 7 is considered alkaline. The solution with a pH 7 is considered neutral. There are certain important points to be kept in mind while measuring soil pH, such as: 1. Soil particles should be kept suspended by stirring just before dipping the electrode ( electrode is either of the two points by which an electric current enters or leaves a battery or any other electrical device). 2. Drying changes the soil pH. In the soil report it is thus essential to mention whether the dried or field moist samples were tested. 3. The ratio of soil: water should also be mentioned in the report as H ion concentration in soil-water suspension decreases with increasing dilution and so the pH increases. 4.Washing the electrode with distilled water from a wash bottle, after every pH measurement has to be done compulsorily. 5.When not in use, electrodes should be kept immersed in distilled water. pH Buffer : A substance that has the property to keep the pH constant in spite of minute change of the system Pharynx : The cavity forming the upper part of the digestive canal Phosphate, Insoluble : The forms of phosphate that are not soluble in water and, hence, are not available to the plants Phosphate Solubilisation : Conversion of insoluble forms of phosphate ( as tri- calcium phosphate) into its soluble form ( as mono-calcium phosphate) Phosphate Solubilising Microorganisms (psms) : The microorganisms that convert the insoluble forms of phosphate (as tri-calcium phosphate) into soluble form Phosphate, Soluble : The forms of phosphate that are soluble in water and hence available to the crop plants (e.g. mono-calcium phosphate) Photosynthesis : A process by which green plants (including algae) can synthesise carbohydrates by reducing carbon dioxide by water and sunlight with the help of chlorophyll pigment Photosynthesis, Oxygenic : see Oxygenic photosynthesis7-14 Glossary of Terms
  • 130. Photosynthesis, Oxygenic — Recycling ProcessPhysical Environment : Physical factors like pH, temperature, light etc. in asystemPhysical Factors : Light, temperature, humidity etc.Pigment : Coloured organic compound that gives colour to the living body, asa whole or in part (e.g. Chlorophyll in plants, Haemoglobin in blood)Plant Growth Promoting Substances : Natural or synthetic compounds thatpromote plant growthPlant Growth Regulator : The natural or synthetic compounds that regulate plantgrowth and developmentPlant Hormones : Natural or synthetic compounds that regulates germination,growth, development and other biological activities in plants, e.g. auxinsPlant Nutrients : Elements required for the growth and development of plantPlant Pathogen : Microbial agents which infect plants and cause diseasePlates : Solid medium in petridishesPollution : A change in the physical, chemical or biological components of theenvironment that affect the living formsPolytelic : Organism breeding several times in whole lifePosterior Region : Distal part of an animal bodyPropagules : Modified plant parts (including seeds) that are used as agents ofpropagationProtease : The enzyme that breaks proteinProtozoa : An animal group comprising of unicellular organismsRecycling : Alteration of different forms of elements in nature in cyclic mannerin relation to timeRecycling of Elements : Sequential alteration of different forms of elements innature in a cyclic mannerRecycling Process : A process by which the elements in the nature are convertedin cyclic manner from one form to other in relation to time and spaceGlossary of Terms 7-15
  • 131. Reduction — Slant Reduction : A chemical reaction where electron or hydrogen atom is added to a molecule. Reproductive Potential : Power of an organism to reproduce and hence increase in number in relation to time Reproductive System : The system in living organism responsible for its propagation Residual Effect : The effect of any fertilizer on the next crop Resistance : Capability to strive against Respiration : A process of breakdown (oxidation) of food substances to release energy Restoration Of Soil Fertility : A phenomenon in which all the events involving increasing soil fertility occur simultaneously in a balanced manner so the soil fertility remain constant in relation to time. Rhizosphere : Volume of the soil surrounding the root system where the influence of the root is governed Saline Soil : A non-sodic soil containing sufficient soluble salts to impair its productivity but not containing excessive exchangeable sodium. The conductivity of the saturation paste extract is greater than 4dS/m. Sandy Soil : Soil with high proportion of sand and very little proportion of clay Seed Pelleting : Covering of individual seed with some protective and inert substances to form small ball-like structure Self-Fertilization : Union of male and female sex cells of same organism Seminal Vesicle : A vesicular structure in the male reproductive system where semen, the fluid containing spermatozoa, is stored Semi-natural Condition : A condition where natural condition is established by assembling the natural components Sewage : Refuse carried-off by roadside drain in domestic region Slant : Solid medium in the test tube where the tube is kept in slanting position7-16 Glossary of Terms
  • 132. Soil Amendment — SolubilisationSoil Amendment : Any substance such as lime, sulphur, gypsum, and sawdust,which is used to alter the properties of a soil, generally to make it more productive.Strictly speaking, fertilizers are soil amendments, but the term is used mostcommonly for materials other than fertilizers.Soil Fertility : The ability of a soil to supply all the essential nutrients in anoptimum amount and balance and in a form readily available to the plantsconcernedSoil Microorganisms : The group of microorganisms (bacteria, actinomycetes,fungi, algae etc.), which live in soilSoil Moisture : Water content of soilSoil Productivity : The capacity of a soil for producing a specified plant or sequenceof plants under a specified system of management i.e. the capacity of the soilto produce crops per unit areaSoil Reaction : It is the degree of acidity or alkalinity expressed as pH; it hastremendous indirect effects on plant growth. Abnormally high or alkaline pH(above 9) or low pH (below 4) is toxic to plants. Between these extremes, theeffect is usually on the nutrient availability. Soil reaction can be modified. Soilscan be made more alkaline (pH increased) by adding calcium, magnesium,sodium or potassium. Soils can be made more acid by adding substances thatproduce strong acids in the soil like fertilizers containing sulphur, ammoniumsulphate or superphosphate.Soil Salinity : The amount of soluble salts in a soil, expressed in terms ofpercentage, parts per million (ppm), or other convenient ratios.Soil Strata : Plural of stratum; soil layerSoil Testing : It is the rapid chemical analysis of a soil to estimate its availablenutrient status, reaction and salinity.Soil Texture : It describes the size of the soil particles. The texture determinesdrainage rate and the total amount of stored water in the soil. On the basis ofsoil texture, soils can be clay, loam or sandy. The greater the quantity of smallerparticles (clay), the less the drainage rate and the more water held in storage.On the other hand sandy soil store little water and have a high drainage rate.Loam (having 20% or less clay, 30-50% silt and 30-50% sand particles) is thebest for cultivation as it is neither too dry nor too wet.Solar Energy : Energy derived from sunlightSolitary : Occurring singlySolubilisation : Conversion of insoluble compounds into their soluble formsGlossary of Terms 7-17
  • 133. Spermathecial Pore — Tolerant Limit Spermathecial Pore : A pore in temporarily female earthworm where spermatozoa are released during sexual copulation Spermatozoa : The male sex cell Sprouted Seeds : Seeds where tender seedlings have been developed at the early stage of germination. Starter Culture : Little amount of microbial culture that is introduced to the sterilised medium to initiate the growth Starter Culture : Little amount of culture added to the production system for the initiation of growth Sterilisation : The process of elimination of any living form from an object Sterilisation, Dry : Making of an object free from any living form by means of dry heat Sterilisation, Moist : Making of an object free from any living form by means of moist heat Stereoscopic Microscope : A modified version of compound microscope where living cells are examined Stunted Growth : Growth that has been checked by a disease Sustainable Effect : And effect which can be kept up over years Symbiosis : An association between two organisms where both are benefited Symbiont : Individual partner in symbiosis Symbiosis : An association between two organisms where both are benefited Symbiotic Bacteria : Bacteria that live in symbiotic association with other organism Symbiotic Microorganism : A microorganism that lives in a mutually beneficial association with another organism Synergistic Interaction : Combined effect of two or more components on the same thing or phenomenon Testis : The male reproductive gland where spermatozoa, the male sex cells, are produced Tolerant Limit : Critical point of stress beyond which the organism cannot tolerate the stress7-18 Glossary of Terms
  • 134. Top Dressing — VolatilisationTop Dressing : An application of fertilizer to a soil after the crop stand has beenestablished.Topography : The physical features of an area of land are called the topography,e.g., an undulating land is divided into three categories, viz., lowland, mediumland, and highland. Separate soil samples should be taken and tested to representeach category as their properties would vary.Toxic : Harmful to living formTransplant Shock : Temporal loss of vitality of seedlings when they are transplantedfrom the nursery bed to the fieldUnfavourable : Not suitableUnfavourable Environmental Condition : The physical, chemical and biologicalstatus of the environment that is not suitable for the growth, development orother biological activity of an organism.Utilisation Efficiency of Chemical Fertilizers : Capability of soil condition to usethe applied chemical fertilizer for crop growth and productivityVas Deferens : The tubular system through which semen are transported fromseminal vesicle to genital poreVesicular Arbuscular Mycorrhyzae (VAM) : A symbiotic association between fungiand root system of higher plants where special structures, vesicles and arbuscles,are developed by the fungi within the rootVentral Side : The front sideVersatile : Turning freely from one place to anotherVesicle and Arbuscle : Structures developed by the fungi within the vascularsystem of root in Vesicular Arbuscular Mycorrhyza (VAM)Vestigial Organ : Underdeveloped and non-functional organ, which is welldeveloped and functional in individuals of other groupsViable Cells : Microbial cells that retain the property to divide and show all themicrobial activities.Volatilisation : Very quick evaporationWater-Holding Capacity : Capacity of a substance to retain water content againstgravitational forceGlossary of Terms 7-19
  • 135. YEM Medium — Notes YEM Medium : Yeast-Extract Mannitol medium for culture of Rhizobium NOTES - You can add words to the glossary here. You could also use the Glossary programme on the CD-ROM to modify this glossary or create your own glossary.7-20 Glossary of Terms
  • 136. BibliographyRoot nodules on a clover plant 8-1
  • 137. BibliographyThe following online sources were consulted while writing this manualOnline museums on microbiology -http://www.bacteriamuseum.orghttp://www.microbe.orghttp://www.ucmp.berkeley.eduThe Tree of Life Web projecthttp://www.tolweb.orgUniversity and college (*.edu) siteshttp://commtechlab.mse.eduhttp://www.cme.msu.edu/sites/dlc-mehttp://helios.bto.ed.ac.uk/bto/http://soils1.cses.vt.edu/http://hcs.osu.edu/hcs200/Intro.htmlhttp://web.reed.edu/academic/departments/biology/nitrogen/http://www.lifesci.ucla.edu/mcdbio/html/ri4.htmhttp://www.ma.psu.edu/~lkh1/iss/http://www.wsu.edu:8080/~hurlbert/pages/101hmpg.htmlhttp://www.ulst.ac.uk/faculty/science/bms/http://webcd.usal.es/web/psm/abstracts/Mariano.htmhttp://www.asahi-net.or.jp/~it6i-wtnb/azolla~E.htmlhttp://www.safs.bangor.ac.uk/dj/lectures/nit-fix/lecture2.htmlIndiana Bioloabhttp://www.disknet.com/indiana-biolabMisc. Sources, Research organisations etc.http://www.socgenmicrobiol.org.ukhttp://www.asmusa.orghttp://www.sanger.ac.uk/Projects/Microbeshttp://www.erin.utoronto.ca/~w3msahttp://www.indiaagronet.comhttp://fukuokafarmingol.nethttp://www.microbiologyonline.org.ukMore information on the Internet may be found by running a searchhttp://www.google.comhttp://www.dmoz.org8-2
  • 138. BibliographyCopyright information for photographs sourced online -Electron micrograph - Azotobacter (c) 1995, Stu PankratzElectron micrograph - Rhizobia on a clover root hair tip - (c) 1995, Frank DazzoBooksThe article on Rhizobium has been reproduced with almost no changes from“Rhizobium, Root Nodules and Nitrogen Fixation”- Society for General Microbiology,January 2002, Edited by Janet Hurst.Basak,R.K. 2000, Fertilizers. Kalyani Publishers Ludhiana, New Delhi.Basak, R.K. 2000, Soil Testing and Fertiliser Recommendation, Kalyani Publishers.New Delhi.Bear, P.E. 1953, Soil and Fertilizers .4th ed. John Wiley and Son, Inc. NewYork.Black.C.A. 1965, Method of Soil Analysis, Part-2 Am. Soc. Agron. Inc. Madison,Wisconsin, USA.Chopra, S.L. and Kanwar, J.S. 1982, Analytical Agricultaral Chemistry. KalyaniPublishers, New Delhi.Guzhov, Yu, 1989, Genetics and Plant breeding for Agriculture, Mir Publishers,Moscow.Graham, P.H, Harris S.C., (Eds) Biological nitrogen fixation technology for tropicalagricultureHesse, P.R. 1994, A Textbook of Soil Chemical Analysis CBS Publishers andDistributors, DelhiJackson, M.L. 1973, Soil Chemical Analysis, Pentice Hall of India Pvt. Ltd. NewDelhi.Kale, R. D. 1998, Earthworm — Cinderella of Organic Farming, Prism Books Pvt.Ltd., Calcutta.Metson, A.J. 1956, Methods of Chemical Analysis for Soil Samples. New ZealandDept. Sci. and Ind, Res. R.E. Owen . Govt. Printer, Wellington, New Zealand.Motsara, M.R., Bhattyacharya, P. and Srivastava, B. 1995. Biofertilizer-Technology,Marketing and Usases. Fertilizer Development and Consultation Organisation,New Delhi. 8-3
  • 139. BibliographyNatesh, S., Chopra V.L., Ramchandran S., 1987, Biotechnology in Agriculture,Oxford Publishers / IBH .Piper,C.S. 1942, Soil and Plant Analysis: a laboratory manual of methods for theexamination of soil and the determination of the inorganic constituents of plants.Univ. of Adelaide, Australia.Peech, M., L.T. Alexander, L.A. Dean and J.F. Reed 1974, Methods of Soil Analysisfor soil fertility investigations U.S.Dept. Agro. Cir. 757. 25P.Tandon, HLS 1993, Method of Analysis of Soils, Plants, Water and Fertlizers.Fertilizer Development and Consultation Organization, NewDelhi.110048 ( India)Yagodin, B.A. (Ed.) 1984, Agricultural Chemistry, Mir Publishers, Moscow.8-4
  • 140. TablesSeedlings being prepared at the VIB nursery 9-1
  • 141. USING THE TABLES N P2O5 K2O1) Rice H 30 20 20 Basal-Full P and K Prekharif Topdressing of N Duration M 40 20 20 1/2 after 1st weeding (100 days) Direct Seeded (15-20 DAS) Aus,HYV,Heera L 60 30 30 1/2 at 30-35 DAS Aditya, Prasanta, Kalyani-2, KhanikaUSING THE TABLES - Sample Table 1This table type shows recommendation of N, P2O5 and K2O on the basisof soil test results.H, M and L refer to High, Medium and Low results from the lab.The blue background line shows Nitrogen recommendations, the orange -Phosphate and the green backgound line shows Potash recommendation.Time of application and other remarks are noted is mentioned in the last column.The crops for which recommendations are available on that page are shown ingreen at the top left or right of the page.The tabulated values are in kg per hectare.For example, say, a farmer wishes to grow HYV rice on his field (which is 2hectares in area) in the pre-kharif season. The soil tests indicate that his fieldis low in N, Medium in P and Low in K.The recommendation (highlighted in red in the sample table) would be(60 x 2 = 120)kg/ha of N, (20 x 2= 40)kg/ha of P2O5 and (30 x 2=60)kg/haof K2O.9-2 RECOMMENDATION TABLES etc.
  • 142. USING THE TABLES HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O I. Hill Zone A.Higher elevation (above 1500 m) Rainfed Potato 100 75 75 125 100 100 150 100 100 Cabbage 100 50 50 120 50 50 150 60 60 Fallow Ginger 120 60 60 120 60 60 120 60 60 Fallow Irrigated Potato 100 75 75 125 100 100 150 100 100 Cabbage 100 50 50 120 50 50 150 60 60 Vegetables 80 40 40 100 50 50 120 60 60 USING THE TABLES - Sample Table 2 This table type is more comprehensive than the previous one. It shows recommendation of N, P2O5 and K2O on the basis of both agroclimatic factors in West Bengal and soil test results. The blue background lines shows Nitrogen recommendations, the orange - Phosphate and the green backgound lines shows Potash recommendation. The agroclimatic region for which recommendations are available on that page are shown in green at the top left or right of the page and also in bold large type at the beginning of each section. The tabulated values are in kg per hectare. For example, say, a farmer wishes to grow cabbages on his irrigated field (which is 1 hectare in area) in the pre-kharif season. His farm is located in a hilly region of Bengal. The soil tests indicate that his field is low in N, Medium in P and Low in K. The recommendation (highlighted in red) would be 150kg of N, 50kg of P2O5 and 60kg of K2O. Further, the crops are listed in recommended cropping sequences. Each season is marked by a yellow square The recommended crops for that season are listed beside and below it. The seasons are in the order Summer/Kharif/Pre- Kharif and Rabi. Thus, a valid sequence for the farmer (with a rainfed plot) would be, say, cabbage in the first season and ginger in the next — but he may not grow potatoes and cabbages because they are listed as alternatives for the same season.RECOMMENDATION TABLES etc. 9-3
  • 143. RICE FERTILIZER RECOMMENDATION USING SOIL TEST RESULTS N P2O5 K2O 1) Rice H 30 20 20 Basal-Full P and K Prekharif Topdressing of N Duration M 40 20 20 1/2 after 1st weeding (100 days) Direct Seeded (15-20 DAS) Aus,HYV,Heera L 60 30 30 1/2 at 30-35 DAS Aditya, Prasanta, Kalyani-2, Khanika 2) Rice H 30 20 20 Basal-1/4 N, full P and K Prekharif Topdressing of N Duration M 50 25 25 1/2 at 15 DAT (100-115days) Transplanted Aus,HYV,Rasi, L 60 30 30 1/4 at 30-35 DAT Tulsi IET-2333, Annada 3) Rice H 20 20 20 Basal-1/2 full P and K Kharif, Topdressing of N Transplanted, Traditional M 40 20 20 1/2 at P.I. Stage and improved In case topdressing of N is not Rupsail, Roghusail, possible due to stagnation of Bhasamanlk, the entire quantity of N upto Patnai-23 30 kg/ ha should be applied SR-26B,Nagra L 50 25 25 as basal. Tilakkachari, water depth upto 50 cm. 4) Rice H 40 20 20 Basal-1/4 N,full P and K Kharif,short Topdressing of N duration (115-125days) M 50 25 25 1/2 at 15 DAT HYV,IR-64, IR-36, Ratna,Khitish Vikash L 60 30 30 1/4 at 30-35 DAT IET-4786,Later 5) Rice H 50 25 25 Basal-1/4 N,full P and K Kharif,Medium Topdressing of N duration (125-135days) M 60 30 30 1/2 at 15 DAT HYV,Jaya,Ajaya9-4 RECOMMENDATION TABLES etc.
  • 144. RICE N P2O5 K2O Kunti, Shasyasree, Vikarmacharya, Prakash, Pratap L 80 40 40 1/4 at 40-45 DAT IR-20 6) Rice Kharif,Medium duration (140-150days) (a)Water depth H 50 25 25 Basal-1/4 N,full P and K (15-30cm.) Topdressing of N HYV IR-42, 1/2 at 21 DAT Shalibahan Pankaj M 60 30 30 1/4 at 55-60 DAT Swarnadhan, Mansarobar, Swarna, Bipasha, Sabitri, Gayitri L 80 40 40 (b)Water depth H 50 25 25 Basal-1/4 N,full P and K (30-50cm.) Topdressing of N Suresh,Biraj Jogen M 60 30 30 1/2 at tillering Tulashi, Rajashree L 80 40 40 1/4 at P.I (c)Water depth H 20 20 20 Basal-1/4 N,full P and K (50-100cm.) Topdressing of N Sabita,Nalini M 40 20 20 1/2 at tillring, 1/4 at P.I. Amulya, if split application of N is not Matangini possible due to stagnation of Purendu, water, entire fertiliser upto the Jitenda L 50 25 25 level of 30 kg/ha along with full P and K need be applied as basal. (d)Water depth Fertiliser dose as (above 100cm) above Dinesh, Prunendu, Jitendra 7) Rice H 80 40 40 Basal-1/4 N,full P and K Boro,HYV,Tulsi Topdressing of N IR-64,Khitish M 100 50 50 1/2 at tillering IR-36, 1/4 at P.I Shasyasree, IET-4786 L 120 60 60RECOMMENDATION TABLES etc. 9-5
  • 145. WHEAT, POTATO,SUGARCANE and JUTE N P2O5 K2O 8) Wheat HYV Earlysown irrigated H 80 40 40 Basal-1/4 N,full P and K K-9107,HP-1731 Topdressing of N Late sown 1/4 at 21 DAS HD-2643, HP-1633 M 100 50 50 1/4 at 40-50 DAS Sonalika Normal sown HUM-468, UP-262, L 120 60 60 Sonalika 9) Potato H 150 100 100 Basal-3/4 N, full P and K K.Jyoti, M 200 125 125 Topdressing of N K.Chandramukhi 1/4 At 1st earthing up K.Badsha L 250 150 150 10) Sugarcane H 100 50 50 Basal-1/3 N,full P and K Early upland Topdressing of N Co J-64 Co 7218 1/3 at 40-45 DAP Co 87263, Co S-687 M 150 75 75 1/3 at 80-90 DAP Medium duration Bo-91, Co 62033 CoS-776 L 200 100 100 11) Jute H 30 20 30 Basal-full P and K Topdressing of N a)Olitorius M 40 20 40 1/2 after 1st weeding JRO-632, (15 DAS) JRO-524 JRO-7835, JRO-878 L 50 25 50 1/2 after 35-42 DAS b)Capsularies H 40 20 20 Basal-full P and K JRC-7447 M 50 25 25 Topdressing of N 1/2 after 1st weeding JRC-212 L 60 30 30 (15 DAS) 1/2 at 30-42 DAS9-6 RECOMMENDATION TABLES etc.
  • 146. OIL SEEDS N P2O5 K2O 12) Oilseeds H 60 30 30 Basal-1/4 N,full P and K Sarsan and Topdressing of N Toria 1/2 at 30-35 DAS a)Irrigated M 80 40 40 Basal-full NPK Benoy,Subinoy L 100 50 50 b)Unirrigated H 30 20 20 Benoy,Subinoy M 40 20 20 In case of rains,20 kg N L 50 30 30 as topdressing 13) Oil seeds Raj a)Irrigated H 80 40 40 Basal-1/2 N,full P and K Sita,Sarama, M 100 50 50 Topdressing of N Bhagirathi L 120 60 60 1/2 at 40-45 DAS b)Unirrigated Sita,Sanjukta 40 20 20 Basal-full NPK Asech 14) Oil seeds Til a)Irrigated Tilottama 50 25 25 Basal-1/2 N,full P and K Rama Topdressing of N 80 40 40 1/2 at Flower initiation b)Unirrigated 25 25 25 Basal-Full NPK for oilseed Tilottama crops, SSP may be chosen as Rama phosphate sources to meet the requirement of S alongwith P. In case of other sources of P, calcium sulphate should be applied. 15) Oil seeds Linseed a) Irrigated 40 20 20 Basal-2/3 N,full P and K Garima,Neela Topdressing of N Mukta 1/3 at 30 DAS b)Unirrigated 20 20 20 Basal-full NPK Neela 16) Oil Seeds Groundnut a)Rainfed, Kharif AK 12-24, JL-24 20 30 45 Basal-full NPK ICGS-44, Somnath, ICGS-II,RECOMMENDATION TABLES etc. 9-7
  • 147. OIL SEEDS and PULSES N P2O5 K2O Girnar-I b)Irrigated H 20 40 60 Basal-full NPK Rabi Summer M 20 60 60 SSP is preferred as phosphate Som nath sources as SSP contains S and Girnar-1 L 20 60 60 P. For further requirement of S,application of 200-250 kg gypsum/ha may be applied before pegging. Liming should be done in low pH soils for correction of acidity and supply of Ca. 17) Oil Seeds H 30 30 30 Basal-1/2 N,full P and K Sunflower M 40 40 40 Topdressing of N Modern L 60 40 40 1/2 at 30 DAS 18) Pulses Pea,Dhusar, GF-68 20 40 20 Basal-full NPK Garden pea Bonavilla Arkel 19) Pulses Arhar 20 50 20 Basal-full NPK TAT-10 (120-125 days) Liming must be done in acid Sweta, Chuni soil having pH below 5.5. (180 days) Rahi Seed treatment with (160 days) Rhizobium culture is recommended. 20) Pulses Gram 20 50 20 Basal-full NPK Mahamaya-1 Seed treatment with Mahamaya-2 Rhizobium culture and Anuradha liming in acid soil are necessary. 21) Pulses Kalai 20 40 20 Basal-full NPK Kalindi Seed treatment with Goutam Rhizobium culture and Sarada liming in acid soil are necessary.9-8 RECOMMENDATION TABLES etc.
  • 148. PULSES and MAIZE N P2O5 K2O 22) Pulses Mug 20 40 20 Basal-full NPK Sonali, Seed treatment with Panna, Rhizobium culture and Pusa, liming in acid soil are Baisakhi necessary. K-850 23) Pulses Lentil 20 50 20 Basal-full NPK Asha,Subrata, Seed treatment with Ranjan Rhizobium culture and liming in acid soil are necessary. 24) Pulses Khesari 1 or 2 DAP Spray (2%) Nirmal, BIOL 25) Pulses Soyabean H 20 30 20 Basal-full NPK JS-2,Pusa-16 M 30 60 40 SSP is preferred as phosphate Soyamax L 40 60 40 sources 26) Maize a) Kharif Hybrid & Composite H 40 20 20 Basal-1/2 N,full P and K Kishan Composite M 60 30 30 Topdressing of N Azad Uttam 1/4 at 30 DAS Composite Megha L 80 40 40 1/4 at tasselling b) Rabi Early-Diara Arun H 60 30 30 Basal-1/2 N,full P and K Tarun,Probha M 90 45 45 Topdressing of N Medium- Agoti-76 1/4 at 30 DAS Late-Vijay, Ganga L 120 60 60 1/4 at tasselling Safed-2,Kishan Composite Vikram, Deccan-101RECOMMENDATION TABLES etc. 9-9
  • 149. VEGETABLES N P2O5 K2O 27) Vegetables H 60 40 40 Basal-1/2 N,full P and K Topdressing of N Summer Bhindi M 80 50 50 1/4 at 21 DAS Parvani Krani L 100 60 60 1/4 at 35 DAS Pusa Sawani 28) Vegetable H 80 40 40 Basal-1/2 N,full P and K Topdressing of N a) Summer Brinjal M 100 50 50 1/4 at 21 DAS Rajpur Selection L 120 60 60 1/4 at 42 DAS b) Hybrid Brinjal 180 100 100 H 100 60 60 Basal-1/2 N,full P and K Topdressing of N 29) Vegetable M 120 75 75 K Topdressing of N Arum L 150 80 80 1/4 at 21 DAS 1/4 at 42 DAS 30) Vegetable H 30 20 20 Basal-1/2 N,full P and K Summer Topdressing of N Bottle gourd, M 40 20 20 1/4 at 21-28 DAS Sweet gourd, Bitter gourd Pumpkim, Cucumber L 60 30 30 31) Vegetable H 90 60 40 Basal-1/2 N,full P and K Summer M 100 60 50 Topdressing of N Pointed gourd L 120 60 50 1/4 at 21 DAP 1/4 at 42 DAP 32) Vegetable H 80 40 40 Basal-1/2 N,full P and K Winter Brinjal M 80 40 40 Topdressing of N L 100 50 50 1/4 at 21 DAT 1/4 at 42 DAT 33) Vegetable H 120 60 60 Basal-1/2 N,full P and K Winter Cabbage M 150 60 80 Topdressing of N L 200 60 90 1/4 at 21 DAT 1/4 at 42 DAT9-10 RECOMMENDATION TABLES etc.
  • 150. VEGETABLES N P2O5 K2O 34) Vegetable H 100 50 50 Basal-1/2 N,full P and K Winter Cauliflower M 120 60 80 Topdressing of N L 150 80 80 1/4 at 15 DAT 1/4 at 35 DAT 35) Vegetable H 100 60 80 Basal-1/2 N,full P and K Winter Onion Topdressing of N Sukh Sagar M 125 100 100 1/2 at 30 DAT Pusa Ratna SSP is preferred as source of Pusa Red L 140 100 100 phosphate as SSP contains S Red Globe besides P and Onion Patnai White requires Sulphur. 36) Vegetable H 60 40 40 Basal-1/2 N,full P and K Winter Beet Topdressing of N Carrot M 75 50 50 1/4 at 21 DAS 1/4 at 42A DAS Turnip For Garlic, SSP is preferred Garlic L 100 60 60 as source of P as Garlic needs S and SSP contains S besides P. 37) Vegetable H 80 40 40 Basal-1/2 N,full P and K Winter Tomato M 100 50 50 Topdressing of N L 120 60 60 1/4 at 21 DAT 1/4 at 42 DAT 38) Vegetable 180 90 90 Basal-1/2 N,full P and K Hybrid Tomato Topdressing of N 1/4 at 21 DAT 1/4 at 42 DAT 39) Vegetable H 40 60 80 Basal-1/2 N,full P and K Radish M 50 60 60 Topdressing of N L 50 60 60 1/4 at 21 DAT 1/4 at 42 DAT 40) Vegetable H 80 60 80 Basal-1/2 N,full P and K Knolkhol M 80 80 80 Topdressing of N L 80 80 80 1/2 at 21 DAT 41) Vegetable H 80 50 60 Basal-1/2 N,full P and K Chilli M 80 50 60 Topdressing of N L 100 60 80 1/4 at 30 DAT 1/4 at 60 DAT 42)Vegetable H 150 80 100 Basal-1/2 N,full P and K Elephant’s foot M 175 100 120 Topdressing of N (Kavur) L 200 120 140 1/2 at 90 DASRECOMMENDATION TABLES etc. 9-11
  • 151. VEGETABLES N P2O5 K2O 43) Vegetable H 100 75 75 Basal-1/2 N,full P and K Winter Tomato M 100 75 75 Topdressing of N L 120 75 75 1/4 at 21 DAT 1/4 at 42 DAT 44) Vegetable H 50 60 50 Basal-3/4 N,full P and K Frenchbean M 50 60 75 Topdressing of N Clusterbean L 60 80 90 1/4 at flower initiation stage Pea 45) Vegetable H 60 50 50 Basal-1/2 N,full P and K Water melon M 80 50 50 Topdressing of N Sugar Baby, L 100 60 60 1/4 at 21 DAS Adhary 1/4 at 42 DAS Ashahi Yamao 46) Vegetable 80 40 40 Basal-1/2 N,full P and K Kakrol Topdressing of N 1/2 at 30 DAP 47) Vegetable 50 50 50 Basal-1/2 N,full P and K Palak Topdressing of N 1/2 at 21 DAS 1/2 at 42 DAS 48) Vegetable 75 50 100 Basal-1/2 N,full P and K Sweet, Topdressing of N Trumeric 1/2 at 30 DAS 49) Vegetable 120 60 60 Basal-1/2 N,full P and K Ginger, Topdressing of N Turmeric 1/4 at 21 DAS 1/4 at 42 DAS 50) Vegetable 90 50 90 Basal-1/2 N,full P and K Katwa Danta Topdressing of N Puin 1/4 at 21 DAS 1/4 at 42 DAS9-12 RECOMMENDATION TABLES etc.
  • 152. WEST BENGAL SPECIFIC RECOMMENDATIONS HILL ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O I. Hill Zone A.Higher elevation (above 1500 m) Rainfed Potato 100 75 75 125 100 100 150 100 100 Cabbage 100 50 50 120 50 50 150 60 60 Fallow Ginger 120 60 60 120 60 60 120 60 60 Fallow Irrigated Potato 100 75 75 125 100 100 150 100 100 Cabbage 100 50 50 120 50 50 150 60 60 Vegetables 80 40 40 100 50 50 120 60 60 B.Lower elevation (above 1500 m) Rainfed Maize 40 20 20 50 25 25 60 30 30 Rice 50 25 25 60 30 30 80 40 40 Mustard 60 30 30 60 30 30 60 30 30 Soyabean 20 30 20 20 60 40 20 60 40 Vegatables 80 40 40 100 50 50 120 60 60 Ragi 40 20 20 50 25 25 50 25 25 Rice 50 25 25 60 30 30 80 40 40 Vegetables 80 40 40 100 50 50 120 60 60 Ginger 120 60 60 120 60 60 120 60 60 Fallow Irrigated Maize 30 20 20 50 25 25 60 30 30 Rice 50 25 25 60 30 30 80 40 40 Potato 100 75 75 125 100 100 150 100 100 Maize 40 20 20 60 30 30 80 40 40 Rice 50 25 25 60 30 30 80 40 40 Vegetables 80 40 40 100 50 50 120 60 60 Vegetables 80 40 40 100 50 50 120 60 60 Rice 40 20 20 50 25 25 60 30 30 Potato 100 75 75 125 100 100 150 100 100RECOMMENDATION TABLES etc. 9-13
  • 153. TERAI ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O II.Terai Zone A.Upland Rainfed Jute 30 20 20 40 20 30 50 25 40 Vegetables 80 40 40 100 50 50 120 60 60 Jute 30 20 30 40 20 40 50 25 50 Niger/Toria 30 20 20 40 20 20 50 30 30 Rice 30 20 20 40 20 20 50 25 25 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 60 30 30 Pulses 20 40 20 20 40 20 20 40 20 Irrigated Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Potato 100 75 75 125 100 100 150 100 100 Rice 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Potato 100 75 75 125 100 100 150 100 100 Rice 30 20 20 30 20 20 30 20 20 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 100 50 50 120 60 60 150 80 80 B.Medium Land Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Wheat 60 30 30 70 35 35 80 40 40 Jute 30 20 20 40 20 40 50 25 50 Wheat 60 30 30 70 35 35 80 40 40 Rice 30 20 20 40 20 20 50 25 25 Vegetables 80 40 40 100 50 50 120 60 60 Irrigated Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Potato 100 75 75 125 100 100 150 100 100 Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 809-14 RECOMMENDATION TABLES etc.
  • 154. TERAI ZONE and GANGETIC ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O Vegetables 100 50 50 120 60 60 150 80 80 Rice 30 20 20 40 20 20 50 25 25 Wheat 80 40 40 100 50 50 120 60 60 Jute 30 20 30 40 20 40 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Tobacco 40 20 40 50 25 50 60 30 60 C.Low Land Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Pulse 2% DAP 2% DAP 2% DAP Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Pulse 2% DAP 2% DAP 2% DAP Irrigated Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Vegetables 80 40 40 80 40 40 100 50 50 Rice 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Vegetables 80 40 40 80 40 40 100 50 50 GM 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Rice 80 40 40 100 50 50 120 60 60 III. Gangetic (New Alluvial Zone) A.Upland Rainfed Jute 30 20 30 40 20 30 50 25 40 Pulse(Kalai) 20 40 20 20 40 20 20 40 20 Jute 30 20 30 40 20 30 50 25 40 Mustard 30 20 20 40 20 30 50 30 30 Rice 30 20 20 40 20 20 50 25 25 Pulse(Kalai) 20 40 20 20 40 20 20 40 20 Rice 30 20 20 40 20 20 50 25 25 Mustard 30 20 20 40 20 30 50 30 30RECOMMENDATION TABLES etc. 9-15
  • 155. GANGETIC ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O Irrigated Jute 30 0 20 40 0 20 50 20 25 Rice 30 20 20 40 20 20 50 25 25 Potato 150 100 100 200 125 125 250 150 150 Jute 30 20 20 40 20 40 50 25 50 Rice 30 20 20 40 20 20 50 25 25 Wheat 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 25 Vegetables 100 50 50 120 60 60 150 80 80 Sesame Rice 30 20 20 40 20 20 50 25 25 Potato 150 100 100 200 125 125 250 150 150 Rice 30 20 20 40 20 20 50 25 25 Mustard 80 40 40 100 50 50 110 60 60 Vegetables 100 50 50 120 60 60 150 80 80 B.Medium Land Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 50 25 25 Jute 30 20 20 40 20 20 50 25 50 Rai,Mustard 30 20 20 40 20 20 50 30 30 Rice 30 20 20 40 20 20 50 25 25 Pulses 20 40 20 20 40 20 20 40 20 Irrigated Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Wheat 80 40 40 100 50 50 120 60 60 Sesame Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Rice 30 20 20 40 20 20 60 30 30 Mustard 60 30 30 80 40 40 100 50 50 Vegetables 100 50 50 120 60 60 150 80 809-16 RECOMMENDATION TABLES etc.
  • 156. GANGETIC and VINDHYA ALLUVIAL ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O C.Low Land Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Pulse 2% DAP 2% DAP 2% DAP (Poyra) G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Pulse 2% DAP 2% DAP 2% DAP (Poyra) Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Oilseed 20 20 20 20 20 20 20 20 20 (Linseed Poyra) Irrigated G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Rice 80 40 40 100 50 50 120 60 60 Sesame 50 25 25 50 25 25 50 25 25 Rice 30 20 20 40 20 20 60 30 30 IV. Old (Vindhya Alluvial Zone) A. Upland Rainfed Rice 30 20 20 40 20 20 50 25 25 Mustard, 30 20 20 40 20 20 50 30 30 Toria Jute 30 20 30 40 20 30 50 25 40 Mustard 30 20 20 40 20 20 50 30 30 Jute 30 20 30 40 20 30 50 25 40 Pulse 20 40 20 20 40 20 20 40 20 Rice 30 20 20 40 20 20 50 25 25 Pulse 20 40 20 20 40 20 20 40 20 (Kalai) Irrigated Jute 30 0 20 40 0 20 50 20 25 Rice 30 20 20 40 20 20 50 25 25 Potato 150 100 100 200 125 125 250 150 150RECOMMENDATION TABLES etc. 9-17
  • 157. VINDHYA ALLUVIAL ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 50 25 25 Wheat 80 40 40 100 50 50 120 60 60 Jute 30 20 20 40 20 20 50 25 25 Rice 30 20 20 40 20 20 50 25 25 Vegetables 100 50 50 120 60 60 150 80 80 Jute 30 0 20 40 0 20 50 20 25 Vegetables 80 40 40 100 50 50 120 60 60 Vegetables 100 50 50 120 60 60 150 80 80 Rice 30 20 20 40 20 20 50 25 25 Rice 30 0 20 40 20 20 50 20 20 Potato 150 100 100 200 125 125 250 150 150 Sesame Rice 30 20 20 40 20 20 50 25 25 Potato 150 100 100 200 125 125 250 150 150 B.Medium Land Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Pulses 20 40 20 20 40 20 20 40 20 Irrigated Jute 30 0 20 40 0 20 50 20 25 Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Wheat 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 50 25 25 Rice 30 0 20 40 0 20 60 20 20 Potato 150 100 100 200 125 125 250 150 150 Rice 30 20 20 40 20 20 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Sesame Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 25 Vegetables 100 50 50 120 60 60 150 80 809-18 RECOMMENDATION TABLES etc.
  • 158. VINDHYA ALLUVIAL and RED-LATERITE ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O C. Lowland Rainfed Jute 30 20 30 40 20 40 50 25 50 Rice 30 20 20 40 20 20 60 30 30 Pulse/ 2% DAP 2% DAP 2% DAP Oilseeds Poyra Khesari Linseed Mung 20 40 20 20 40 20 20 40 20 Rice 30 20 20 40 20 20 60 30 30 Irrigated G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Rice 80 40 40 100 50 50 120 60 60 Sesame 50 25 25 50 25 25 50 25 25 Rice 30 20 20 40 20 20 60 30 30 V.Red & Laterite Zone A.Upland Rainfed G.Nut 20 30 45 20 30 45 20 30 45 Kulthi 20 40 0 20 40 0 20 40 0 Soyabean 20 30 20 30 40 30 40 30 30 Niger 30 20 20 40 20 20 50 30 30 Rice 30 20 20 40 20 20 60 30 30 Kulthi 20 40 0 20 40 0 20 40 0 Maize 40 20 20 60 30 30 80 40 40 Oilseed 30 20 20 40 20 20 50 30 30 (Toria/ Niger/ Safflower Millet 30 20 20 40 20 20 40 20 20 (Jowar/ Ragi) Kulthi 20 40 0 20 40 0 20 40 0 Arhar 20 50 20 20 50 20 20 50 20 FallowRECOMMENDATION TABLES etc. 9-19
  • 159. RED-LATERITE ZONE HIGH MEDIUM LOW N P2O 5 K2O N P2O 5 K2O N P2O 5 K2O Irrigated Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 20 Potato 150 100 100 200 125 125 250 150 150 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 50 25 25 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 80 40 40 100 50 50 120 60 60 Vegetables 80 20 40 100 25 50 120 30 60 Vegetables 100 50 50 120 60 60 150 80 80 Maize 40 20 20 60 30 30 80 40 40 Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 B.Medium Land Rainfed Rice 30 20 20 40 20 20 60 30 30 Sesame 20 20 20 30 20 20 40 20 20 Rice 30 20 20 40 20 20 60 30 30 Pulse 20 40 20 20 40 20 20 40 20 Rice 30 20 20 40 20 20 60 30 30 Mustard 30 20 20 40 20 20 50 30 30 Irrigated Rice 30 20 20 40 20 20 50 25 25 Rice 30 0 20 40 0 20 50 20 20 Potato 150 100 100 200 125 125 250 150 150 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 20 Wheat 80 40 40 100 50 50 120 60 60 Sesame Rice 30 20 20 40 20 20 60 30 30 Potato 150 100 100 200 125 125 250 150 150 Maize 40 20 20 60 30 30 80 40 40 Rice 30 20 20 40 20 20 60 30 30 Mustard 80 40 40 100 50 50 120 60 60 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 20 Potato 150 100 100 200 125 125 250 150 1509-20 RECOMMENDATION TABLES etc.
  • 160. RED-LATERITE ZONE and COASTAL ZONE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O C. Low Land Rainfed G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Pulse 2% DAP 2% DAP 2% DAP (Poyra) Irrigated G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Rice 80 40 40 100 50 50 120 60 60 Rice 50 25 25 50 25 25 50 25 25 Sesame 30 20 20 40 20 20 60 30 30 VI.Coastal Zone Saline A. Upland Rainfed Fallow Vegetables 80 40 40 100 50 50 120 60 60 Chilli 40 20 20 50 25 25 60 30 30 Rice 30 20 20 40 20 20 60 30 30 Fallow Irrigated Fallow Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 60 30 30 Watermelon 80 40 40 100 50 50 120 60 60 Vegetables 80 40 40 100 50 50 120 60 60 Vegetables 50 25 25 60 30 30 100 50 50 Vegetables 100 50 50 120 60 60 150 80 80RECOMMENDATION TABLES etc. 9-21
  • 161. COASTAL ZONE - SALINE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O B. Medium Land Rainfed Fallow Rice 30 20 20 40 20 20 60 30 30 Pulse/ 2% DAP 2% DAP 2% DAP (Poyra Khesari) Irrigated Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 0 40 0 0 50 20 20 Chilli 80 50 60 80 50 60 100 60 80 Fallow Rice 30 20 20 40 20 20 60 30 30 Watermelon 80 40 40 100 50 50 120 60 60 Vegetables 80 40 40 100 60 60 150 80 80 Rice 30 0 0 40 0 0 50 20 20 Vegetables 100 50 50 120 60 60 150 80 80 Fallow Rice 30 20 20 40 20 20 60 30 30 Cotton 40 20 20 40 20 20 40 20 20 C.Low Land Rainfed Fallow Rice 30 20 20 40 20 20 40 20 20 Pulse/ 2% DAP 2% DAP 2% DAP (Khesari Poyra) Irrigated G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Sunflower 30 30 30 40 40 40 60 40 40 G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Chilli 40 20 20 60 30 30 80 40 40 Fallow Rice 30 20 20 40 20 20 60 30 30 Cotton 40 20 20 40 20 20 40 20 209-22 RECOMMENDATION TABLES etc.
  • 162. COASTAL ZONE - LESS SALINE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O Less Saline A. Upland Rainfed Fallow Vegetables 80 40 40 100 50 50 120 60 60 Toria 30 20 20 40 20 20 50 30 30 Fallow Rice 30 20 20 40 20 20 60 30 30 Kalai 20 40 20 20 40 20 20 40 20 Khesari 2% DAP 2% DAP 2% DAP Irrigated Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 20 Wheat 80 40 40 100 50 50 120 60 60 G.Nut 20 30 45 20 30 45 20 30 45 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 80 40 40 100 50 50 120 60 60 Vegetables 50 25 25 60 30 30 100 50 50 Vegetables 100 50 50 120 60 60 150 80 80 Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 50 25 25 Mustard 60 30 30 80 40 40 100 50 50 Vegetables 80 40 40 100 50 50 120 60 60 Rice 0 20 20 40 20 20 60 30 30 Chilli 40 20 20 60 30 30 80 40 40 B.Medium Land Rainfed Fallow Rice 30 20 20 40 20 20 60 30 30 Fallow Rice 30 20 20 40 20 20 60 30 30 Barley 20 20 20 30 25 25 40 30 30 Fallow Rice 30 20 20 40 20 20 60 30 30 Sunflower/ 20 20 20 20 20 20 30 30 30 SafflowerRECOMMENDATION TABLES etc. 9-23
  • 163. COASTAL ZONE - LESS SALINE HIGH MEDIUM LOW N P2O5 K2O N P2O5 K2O N P2O5 K2O Irrigated Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 0 40 0 0 50 20 20 Wheat 80 40 40 100 50 50 120 60 60 Rice 30 20 20 40 20 20 60 30 30 Chilli 40 20 20 60 30 30 80 40 40 G.Nut 20 30 45 20 30 45 20 30 45 Rice 30 20 20 40 20 20 60 30 30 Vegetables 100 50 50 120 60 60 150 80 80 C.Low Land Rainfed Fallow Rice 30 20 20 40 20 20 60 30 30 Cotton 40 20 20 40 20 20 40 20 20 Fallow Rice 30 20 20 40 20 20 60 30 30 Sunflower 20 20 20 20 20 20 30 30 30 Rice 30 0 20 40 0 20 60 20 30 Pulses 2% DAP (Poyra) Irrigated Vegetables 80 40 40 100 50 50 120 60 60 Rice 30 0 20 40 0 20 50 20 20 Sugarbeet 80 40 40 100 50 50 120 60 60 G.M. 0 25 0 0 25 0 0 25 0 Rice 30 0 20 40 0 20 60 0 30 Rice 80 40 40 100 50 50 120 60 60 Mung 20 40 20 20 40 20 20 40 20 Rice 30 20 20 40 20 20 50 25 25 Rice 80 40 40 100 50 50 120 60 609-24 RECOMMENDATION TABLES etc.
  • 164. Late monsoon Pre-monsoon Post-monsoon Fruit FYM N P2O5 K2O FYM N P2O5 K2O FYM N P2O5 K2O kg g g g kg g g g kg g g g Mango 50 1 kg 50 750 750 Litchi 40 250 375 375 40 250 375 375 Jackfruit 40 250 375 375 40 250 375 375 Sapota 40 250 375 375 40 250 375 375 Cashewnut 15 1 kg 1 kg 330RECOMMENDATION TABLES etc. Custard Apple 20 125 150 150 20 125 150 150 Pomegranate 20 125 125 125 20 125 125 125 Coconut 40 250 125 500 40 250 125 500 Guava 25 200 200 150 25 200 150 150 Pineapple 0.5 5 2.5 5 5 2.5 5 Citrus 20 130 130 130 20 130 130 130 20 130 130 130 Papaya 3 months 3 months 3 months 5 50 50 50 5 50 50 50 5 50 50 50 Banana 1st 30 day period 2nd 45 day period 3rd 45 day period 10 25 10 20 - 25 10 20 10 25 10 20 4th 45 day period 5th 45 day period 6th 45 day period - 25 10 20 - 25 10 20 - 25 10 20 7th 45 day period 8th 45 day period - 25 10 20 - 25 10 20 All figures are per plant per year9-25 NPK requirement of FRUIT CROPS
  • 165. RHIZOBIUM NODULATION - MOST PROBABLE NUMBERS n=4 n=2 s=10 40 20 >7 x 108 39 38 19 6.9 x 108 37 3.4 x 108 36 18 1.8 x 108 35 1.0 x 108 34 17 5.9 x 107 s=8 33 3.1 x 107 32 16 1.7 x 107 >7 x 106 31 1.0 x 107 30 15 5.8 x 106 6.9 29 3.1 x 106 3.4 28 14 1.7 x 106 1.8 27 1.0 x 106 1.0 26 13 5.8 x 105 5.8 x 105 s=6 25 3.1 x 105 3.1 24 12 1.7 x 105 1.7 >7 x 104 23 1.0 x 105 1.0 22 11 5.8 x 104 5.8 x 104 6.9 21 3.1 x 104 3.1 3.4 20 10 1.7 x 104 1.7 1.8 19 1.0 x 104 1.0 1.0 18 9 5.8 x 103 5.8 x 103 5.8 x 103 17 3.1 x 103 3.1 3.1 16 8 1.7 x 103 1.7 1.7 15 1.0 x 103 1.0 1.0 14 7 5.8 x 102 5.8 x 102 5.8 x 102 13 3.1 x 102 3.1 3.1 12 6 1.7 x 102 1.7 1.7 11 1.0 x 102 1.0 1.0 10 5 5.8 x 101 5.8 x 101 5.8 x 101 9 3.1 x 101 3.1 3.1 8 4 1.7 x 101 1.7 1.7 7 1.0 x 101 1.0 1.0 6 3 5.8 x 1 5.8 x 1 5.8 x 1 5 3.1 x 1 3.1 3.1 4 2 1.7 x 1 1.7 1.7 3 1.0 x 1 1.0 1.0 2 1 0.6 x 1 0.6 0.6 1 <0.6 <0.6 <0.6 0 0 Approx range 109 107 1059-26 RECOMMENDATION TABLES etc.
  • 166. RHIZOBIUM NODULATION - MOST PROBABLE NUMBERS Using the table This table is used to find the number of active rhizobia in your culture or carrier bags. Active rhizobia refers to the Rhizobia capable of forming nodules. This number can be calculated by comparing your test results with results obtained in tests with large numbers of replicates. The large number gives statistically accurate results. Comparing the results allows you to deduce the most probable number of active rhizobia in your carrier. After performing a nodulation efficiency test with dlutions of your carrier, you would end up with a table that looks like the one on page 2-82. On the table on the opposite page, n is the number of replicates - the number of tubes of each dilution - in the set. s is the number of dilutions. To find the most probable number of nodulating rhizobia, look for the number of nodulated units you found under the cooresponding replicates column. The cooresponding entry in the appropriate dilutions column (labelled s=10 etc.). For example, in the sample table on page 2-82, a total of 21 nodules were formed with 4 replicates. Thus, we look for the number ‘21’ under the ‘n=4’ column. Then, we move along the row to the corresponding entry under the ‘s=10’ column since we tested with 10 dilutions. The most probable number of rhizobium nodulating units is 3.1x104RECOMMENDATION TABLES etc. 9-27
  • 167. LIME RECOMMENDATION USING SMP TEST VALUES Target pH Using the table Sample pH 6.4 6.8 This table is used to determine the amount of pure CaCO3 required to increase the pH of one acre of 4.8 10.6 12.4 land. 4.9 10.1 11.8 Pure CaCO3 required, in tons per acre The ‘Sample pH’ column lists pH values obtained from a pH test 5.0 9.6 11.2 using the SMP buffer solution. 5.1 9.1 10.6 The ‘Target pH’ columns list the amount of pure CaCO3 required 5.2 8.6 10.0 to raise the pH of one acre of land to 6.4 and 6.8. 5.3 8.2 9.4 This table lists values for pure 5.4 7.7 8.9 CaCO3 and not commercial lime. 5.5 7.2 8.3 For conversion, use the following values — 5.6 6.7 7.1 100kg pure CaCO3 5.7 6.2 7.1 = 56kg pure CaO 5.8 5.7 6.5 = 74kg pure Ca(OH)2 = 84kg pure MgCO3 5.9 5.2 6.0 = 92kg pure CaCO3.MgCO3 = 116kg pure CaSiO3 6.0 4.7 5.4 1 bigha = 0.33 acre = 0.13 hectare 6.1 4.2 4.8 6.2 3.7 4.2 6.3 3.2 3.7 6.4 2.7 3.1 6.5 2.2 2.5 6.6 1.7 1.9 6.7 1.2 1.49-28 RECOMMENDATION TABLES etc.
  • 168. A few tips on Lime recommendation —1) Fine textured acidic soils with high organic carbon content require more limethan coarse soils that are low in organic carbon. Liming coarse textured soil isbest done in split doses as overliming is a risk in these soils.2) Lime is corrosive and is hazardous to seedlings. Liming should be done atleasta couple of weeks before transplanting the crop. Also, advise the farmer to weargloves and a mask while liming his or her field.3) Root penetration of most crops is 6 inches (15cm). The recommendationtables assume this to be the case. Some crops have roots that penetrate 9 inches(23 cm) into the soil. If the farmer intends to grow such a crop, increase therecommendation by 50%.4) Fine liming materials such as quicklime (CaO) react with soil much faster thancoarse liming materials. Therefore, fine liming materials are to be applied morefrequently and in less quantities than coarse materials.5) Liming a neutral or alkaline soil is a waste of time and money.6) If, for whatever reason, liming materials are unavailable, recommend aminimum dose of 300-500kg per hectare. This will not significantly neutralisethe soil in the plot but will act as a Ca fertilizer because acidic soils are oftendeficient in Calcium.7) Prolonged use of calcitic limestone causes deficiency of magnesium in thefield. To offset this, recommend application of a magnesium supplying mineral.A few such minerals are — MgSO4 (Epsom salts) MgO (Magnesia) and Mg(NO3)2.Dolomitic limestone (CaCO3.MgCO3) may also be recommended.8) The final acidity of the soil is critical for a good yield. Crops that require ahigh dosage of lime amendment — crops that require a neutral or nearly neutralsoil — are: wheat, tobacco and sweet potatoes. Crops that require less limeare: potatoes, rice, rye and watermelon. Crop such as tea, coffee (arabica) andpineapples can survive in relatively acidic soils and require very little limeamendment. These estimates, again, depend on a whole lot of other factors suchas terrain, soil texture and irrigation types.9) Talk to the farmer! Recommendation of soil amendments (fertilizer included)is not really an exact science. Socio-economic factors play an important role inthe farmer-field-crop relationship. For instance, a farmer may not have fundsto comply with an optimal recommendation. In such cases, the ‘optimal’recommendation must take into account his available funds... 9-29
  • 169. LIST OF ABBREVIATIONS Most abbreviations are expanded in the main body of the manual or in the Glossary. ARA - Acetylene Reduction Assay CFU - Colony forming unit EBT (indicator) - Erichrome Black T EDTA - Ethylene Diamine Tetraacetic Acid FYM - Farm yard manure SMP (extractant buffer) - Shoemaker, MacLean and Pratt (the scientists who devised the pH determination test using this chemical.9-30
  • 170. INFORMATION SHEETSample No. X-base IDDate of CollectionFarmer’s nameAddressG.PBlockMouza No.Plot No.Land area.Land type : Upland - medium land - low landSoil texture : Sandy - Loam - ClayIrrigation facility : Irrigated area - Non-irrigated area.Source of water : River - Pond - Canal - Tube well - WellDrainage condition : Good - Medium - Bad.Slope of the land : No slope - slight slope - middle slope - steep slope.Height of water level in chary rice :Information on previous crop :Name and variety of the crop :Dose of organic manure, if applied :Dose of fertilizer, if applied :Yield :Information of the crop that will be grown:Name and variety of the crop :Season (Pre kharif / kharif / rabi ) : SIGNATURE 9-31

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