method of soil testing

1. VIKASRATNA SARKAR SAHEB RAWAL
College of Agriculture Dondaicha
TAL- SHINDHKHEDA,DIST-DHULE
AFILIATED TO MAHATMA PHULE KRISHI VIDYAPEETH RAHURI
STUDENT READY PROGRAM
Experiential Learning Programme As per V dean’s
Committee
SRP-EL SSAC-405 (Soil,Water,Plant,And Fertilizer Analysis)
Under Guidance of: Prof. Akshay Padghan
NAME OF THE STUDENT: MR.Aakash Bhagwan Buwa
REGISTRATION NO: ADO-28-2018

2. This Presentation Contain
1. What is Soil testing
2. Why do we need ‘Soil Testing’?
3. When and How to take a sample of a soil?
4. Soil testing kit
5. Soil sampling method
6. Preparation of soil sample
7. Soil testing procedure
8. Extraction /Analysis
9. Soil testing parameters
10. Interpretation of soil analysis data
11. Advantages of soil testing
12. Disadvantage of soil testing
13. conclusion

3. What is Soil testing
1. Soil testing is the use of various laboratory methods to
discover chemical and/or biological qualities of a soil
sample as part of an overall soil management plan
2. Soil testing can also be used to discover the presence of
contaminants such as heavy metals or pollutants

4. Why do we need ‘Soil
Testing’?
Soil is an important matter for cultivation of any type of crop. Soil supplies many necessary
nutrients required for healthy growth of a crop. The yield is largely dependent on the soil in
which the crop grows. So, before cultivation, it is very important to check the soil for its
nutrients. By checking the soil you will know whether the soil is having enough amount of
nutrients or not. If any nutrient is less or more than the required amount, necessary measures
can be taken.
In short following are the benefits of ‘soil testing’:
 Soil testing encourages plant growth by providing the best fertilizer recommendations.
 It diagnoses whether there is too little or too much of a nutrient.
‘Soil testing’ promotes environmental quality.
 It also saves money that might otherwise be spent on unneeded fertilizer.

5. When and How to take a
sample of a soil?
Soil sample must be taken at the right time and in the right way as described here:-
1. Before planting anything in the field and after you take out the crop
2. Before application of any organic or chemical fertilizers
3. Three months after application of any organic or chemical fertilizers
 Do not take soil samples from the following areas:-
1. Where cattle graze
2. Under a tree
3. Garbage area

6. Soil Testing Kit
Portable soil testing kits enable farmers
to take it to fields and take
Measurements
Most common kits helps us to find the
pH and primary nutrients (N,P and K)
Kits can also help in finding all nutrients but
its expensive
Soil sample is first taken using a spade or
trowel

7. Soil Sampling Method
1. Random method
2. Zigzag method
3. Subsampling method

8. Preparation Of Soil Sample
Sieving
Grinding
Mixing
Storing

9. Soil Testing Procedure
1. For ‘soil testing’, soil is taken from 15 different places.
2. Dig a ‘V’ shape pit in the ground which is 15 cm deep.Take soil sample (2 to 3
cm thick) from one side of it.
3. Follow the same procedure to take samples from 15 different places.
4. Clean the samples by removing any garbage if present in the soil.
5. Mix all the samples very well (Make 4 equal parts of the mixed sample.Then
mix two diagonally opposite parts with each other. Repeat the procedure for
4/5 times)
6. Take 0.5 kg of the sample for ‘soil testing’.

10. EXTRACTION /ANALYSIS
1. Main nutrients:-: Nitrogen (N), Phosphorus (P), Potassium(K)
2. Secondary nutrients: Calcium (Ca), Magnesium (Mg), Sulphur (S)
3. Micro nutrients: Iron (I), boron (B), zinc (Zn), copper (Cu), molybdenum (Mo), chlorine (Cl),
maganese(Mn)
4. Nutrients from air: Carbon (C), hydrogen (H)
5. Nutrients from water: Oxygen (O)Apart from above nutrients, there are some other
parameters which also affect plant growth.These parameters are: Soil pH, Soil EC (Electrical
Conductivity) and Soil OC (OrganicCarbon).To judge the health of soil, these parameters
should be checked.

11. Soil testing parameters
1. Soil pH
2. EC
3. SOC
4. Available N - Alkaline potassium permanganate
5. Available P - Sodium bicarbonate
6. Available K - Ammonium acetate
7. Available Ca, Mg and S
8. Available micronutrients

12. Soil PH
Measured using pH meter
pH meter has two electrodes – one reference and
one standard electrode
The pH meter is submerged in soil-water solution
Difference in H+ concentration between soil
suspension and glass electrode gives rise to an
electrometric potential
This potential is measured
and converted to pH units
Soil pH interpretation
pH range Soil type
<4.5 Extremely acidic
4.5-5.0 Very strongly acidic
5.1-5.5 Strongly acidic
5.6-6.0 Medium acidic
6.1-6.5 Slightly acidic
6.6-7.3 Neutral
7.4-8.0 Mildly alkaline
8.1-9.0 Strongly alkaline
>9.0 Very strongly al

13. Electrical Conductivity
Electrical conductivity is the capacity of soils to conduct
electricity
Since ions contribute to EC, EC tells us about the salt
concentration in soil

14. Soil Organic Carbon
Soil organic carbon
 SOC is an integral part of organic matter
Organic carbon is measured using Walkley -Black method (1934)

15. Available Nitrogen (N)
Procedure
Method : Alkaline potassium permanganate
1. All the reagents needed below are prepared first
2. 20g soil is taken in a distillation flask
3. 20 ml water and 100 ml 0.32% KMnO4solution is added to it
4. 25 ml of N/ 50 (0.02 N) H2SO4 is pipette out in a conical flask. 2-3 drops of methyl red
indicator is added and the end of delivery tube of distillation flask is dipped into it
5. 100 ml of 2.5% NaOH solution is added into the flask and corked immediately.
6. Ammonia gas is distilled from the distillation flask and collected in
H2SO4solution.Continue distillation till the evolution of ammonia ceases completely (test
by bringing moist red litmus paper near the outlet of the condenser, which will turn blue as
longas ammonia is being evolved).
7. Titrate the excess of H2SO4 against N/50 (0.02 N) NaOH and note down the volume of
NaOH used. The end point is reached when the colour changes from pink to yellow.

16. Available Potassium (K)
Procedure
Method - Ammonium acetate
1. Take a 5g of soil sample in 250ml conical flask
2. Add 25ml of ammonium acetate extractant
3. Shake for 5min and then filter
4. Determine K in the filtrate with the flame
photometer

17. Available Phosphorus(P)
Procedure
Method - Sodium bicarbonate
1. Add 5 ml of extracting solution to each of the P standard solution.
2. Add 5 ml Dickman and Bray’s reagent to all standard solutions (development of yellow
colour).
3. To avoid fluoride interference, 7.5 ml 0.8 M boric acid (50 g H3BO3 per lt) may be added.
4. Mix with about 5 ml of distilled water.
5. Add 1 ml of SnCl2solution and make up to the mark with distill water (development of
blue colour).
6. Measure the intensity of the blue colour after 10 min, using 660 nm red filter in
colorimeter.
7. Plot the transmittance reading (%T) of the standard on the ordinate against the conc. in
ppm in semi logarithmic graph paper for a straight line relationship.

18. Interpretation Of Soil Analysis
Data
For macronutrients, the results generally classified into categories of
supply, e.g.: low, medium and high (see Table below). For these
categories, the nutrient amounts required for an optimal or stated
yield level are estimated. For micronutrients, a critical level is
generally used to decide whether an application of that nutrient is
needed.

19. Advantages of soil testing
Improving yields and profitability because you are providing
necessary nutrients to your crops.
Increasing consistency of nutrient availability across a field.
More uniform crop growth.
More uniform plant maturity.

20. Disadvantages of soil testing
Samples are not obtained; the soil tested cannot be positively
identified.
The fundamental behaviour of soils during testing is not well
understood.
Drainage conditions during testing are not known.
Consistent, rational interpretation is often difficult and uncertain.

21. Conclusion:
 Soil testing is an inexpensive practice to learn about the
ability of soils to support crop growth. With knowledge of what
each soil test value means, growers can make more informed
crop input decisions to minimize risk and maximize profitability.

22. THANK YOU