many microorganisms from the soil are still undiscovered, while most of the discovered microbes cannot be cultivated in the artificial medium due to various reasons. This is briefly discussed in this presentation.
many microorganisms from the soil are still undiscovered, while most of the discovered microbes cannot be cultivated in the artificial medium due to various reasons. This is briefly discussed in this presentation.
he rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome.
The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.
Soil organic matter has long been recognized as one of the most important components in maintaining soil fertility, soil quality, and agricultural sustainability. The soil zone strongly influenced by plant roots, the rhizosphere, plays an important role in regulating soil organic matter decomposition and nutrient cycling. Processes that are largely controlled or directly influenced by roots are often referred to as rhizosphere processes. These processes may include exudation of soluble compounds, water uptake, nutrient mobilization by roots and microorganisms, rhizosphere-mediated soil organic matter decomposition, and the subsequent release of CO2 through respiration. Rhizosphere processes are major gateways for nutrients and water. At the global scale, rhizosphere processes utilize approximately 50% of the energy fixed by photosynthesis in terrestrial ecosystems, contribute roughly 50% of the total CO2 emitted from terrestrial ecosystems, and mediate virtually all aspects of nutrient cycling. Therefore, plant roots and their rhizosphere interactions are at the center of many ecosystem processes. However, the linkage between rhizosphere processes and soil organic matter decomposition is not well understood. Because of the lack of appropriate methods, rates of soil organic matter decomposition are commonly assessed by incubating soil samples in the absence of vegetation and live roots with an implicit assumption that rhizosphere processes have little impact on the results. Our recent studies have overwhelmingly proved that this implicit assumption is often invalid, because the rate of soil organic matter decomposition can be accelerated by as much as 380% or inhibited by as much as 50% by the presence of live roots. The rhizosphere effect on soil organic matter decomposition is often large in magnitude and significant in mediating plant-soil interactions.
Soil enzyme increase the reaction rate at which plant residues decompose and release plant available nutrients.
The substance acted upon by soil enzyme is called substrate.
Eg. Glucosidase(soil enzyme) cleaves glucose from glucoside(substrate),
1.Constitutive
Always present in nearly constant amounts in a cell (not affected by addition of any particular substrate…genes always expressed.) (pyro-phosphatase).
2.Inducible
Present only in trace amounts or not at all, but quickly increases in concentration when its substrate is present. (Amidase).
Both enzymes are present in the soil.
Oxidoreductases – Oxidation reduction reaction (Dehydrogenase, Catalase, Peroxidase)
Transferases – The transfer of group of atoms from donor to an acceptor molecule. (Aminotransferases, Rhodonase)
Hydrolases – Hydrolytic cleavage of bonds. (Phosphatase, Cellulase, Urease)
Lysates – Cleavage of bonds other than hydrolysis or oxidation.
Isomerases – Isomerisation reaction.
Ligases – Formation of bonds by the cleavage of ATP. (Acetyl-CoA carboxylase)
Quality control and constraints in biofertilizer production technologyVENKATESH AGRI
Biofertilizers or microbial inoculants are the carrier-based preparations containing sufficient number of microorganisms in a viable state inoculated to soil or seed to augment the nutrient availability to plant by enhancing the growth and proliferation of microorganisms.
Use of biofertilizers is one of the important components of integrated nutrient management, as they are cost effective and renewable source of plant nutrients to supplement the chemical fertilizers for sustainable agriculture This ppt is very essential & useful for vegetable crop production, because present time the farmers was used fertilizers is more compared to the recommended dose of fertilizer. so i can suggested the farmers use of bio fertilizer because they have farmers ecofriendly.
Sulfur is a chemical element with symbol S and atomic number 16 with atomic mass 32.065.
It is abundant, multivalent, brittle, yellow, tasteless, odourless and non-metallic element.
Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth.
In the Bible, sulfur is called brimstone .
Today, almost all elemental sulfur is produced as a by product of removing sulfur-containing contaminants from natural gas and petroleum.
Most soil sources of S are in the organic matter and therefore concentrated in the top soil or low layer.
Under normal conditions, sulfur atom forms cyclic octatomic molecules with a chemical formula S8.
Sulphur is the most abundent and widely distributed element in the nature and found both in free as well as combined states.
Microbial biomass in soil, measurement by chloroform fumigation incubation method, limits of measurement of microbial biomass, why microbes are important in the soil, why microbial biomass is important in the soil
Soils give a mechanical support to plants from which they extract nutrients. soil provides shelters for many animal types, from invertebrates such as worms and insects up to mammals like rabbits, moles, foxes and badgers. It also provides habitats colonised by a staggering variety of microorganisms. This module is about the microbial life in soils.
Effect of Aloe Vera wastes on physico-chemical properties and microbiological...IJEABJ
The aim of the present study was to explore the potential for using aloe vera wastes as amendment for soil to improve its fertility. Soil was exposed to four concentrations of aloin (rich in HAP) for 0, 7, 14 and 28 days. Physico-chemical parameters were analyzed: soil Ph, organic matter (OM), nitrogen, phosphorus, and cation exchange capacity (CEC). The activity of seven enzymes implicated in the C, N and S cycles were measured. Microbial Biomass was determined by the method of substrate induced respiration. BiologEcoplates (Biolog Inc., Hayward, CA) were used to estimate soil microbial functional diversity. Our findings suggested a decrease on phosphorus and nitrogen content and an increase on CEC after aloin addition. Also, a decrease on microbial biomass and enzymes activities was observed, except for FDA. Ecoplates results demonstrate a decrease on microbial activities depending on the incubation time. Moreover, our results indicated that bacterial communities of the tested soils have more affinity to consume substrates as Amino acids and polymers. Our results should be carefully considered in view of the agriculture waists reuse for a sustainable agriculture
Soil Health definition and relationship to soil biology
Characteristics of healthy soil
Assessment of soil health
Framework for evaluating soil health
Indicators
Types of indicators
Biological indicators
Role of biological indicators
he rhizosphere is the narrow region of soil or substrate that is directly influenced by root secretions and associated soil microorganisms known as the root microbiome.
The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.
Soil organic matter has long been recognized as one of the most important components in maintaining soil fertility, soil quality, and agricultural sustainability. The soil zone strongly influenced by plant roots, the rhizosphere, plays an important role in regulating soil organic matter decomposition and nutrient cycling. Processes that are largely controlled or directly influenced by roots are often referred to as rhizosphere processes. These processes may include exudation of soluble compounds, water uptake, nutrient mobilization by roots and microorganisms, rhizosphere-mediated soil organic matter decomposition, and the subsequent release of CO2 through respiration. Rhizosphere processes are major gateways for nutrients and water. At the global scale, rhizosphere processes utilize approximately 50% of the energy fixed by photosynthesis in terrestrial ecosystems, contribute roughly 50% of the total CO2 emitted from terrestrial ecosystems, and mediate virtually all aspects of nutrient cycling. Therefore, plant roots and their rhizosphere interactions are at the center of many ecosystem processes. However, the linkage between rhizosphere processes and soil organic matter decomposition is not well understood. Because of the lack of appropriate methods, rates of soil organic matter decomposition are commonly assessed by incubating soil samples in the absence of vegetation and live roots with an implicit assumption that rhizosphere processes have little impact on the results. Our recent studies have overwhelmingly proved that this implicit assumption is often invalid, because the rate of soil organic matter decomposition can be accelerated by as much as 380% or inhibited by as much as 50% by the presence of live roots. The rhizosphere effect on soil organic matter decomposition is often large in magnitude and significant in mediating plant-soil interactions.
Soil enzyme increase the reaction rate at which plant residues decompose and release plant available nutrients.
The substance acted upon by soil enzyme is called substrate.
Eg. Glucosidase(soil enzyme) cleaves glucose from glucoside(substrate),
1.Constitutive
Always present in nearly constant amounts in a cell (not affected by addition of any particular substrate…genes always expressed.) (pyro-phosphatase).
2.Inducible
Present only in trace amounts or not at all, but quickly increases in concentration when its substrate is present. (Amidase).
Both enzymes are present in the soil.
Oxidoreductases – Oxidation reduction reaction (Dehydrogenase, Catalase, Peroxidase)
Transferases – The transfer of group of atoms from donor to an acceptor molecule. (Aminotransferases, Rhodonase)
Hydrolases – Hydrolytic cleavage of bonds. (Phosphatase, Cellulase, Urease)
Lysates – Cleavage of bonds other than hydrolysis or oxidation.
Isomerases – Isomerisation reaction.
Ligases – Formation of bonds by the cleavage of ATP. (Acetyl-CoA carboxylase)
Quality control and constraints in biofertilizer production technologyVENKATESH AGRI
Biofertilizers or microbial inoculants are the carrier-based preparations containing sufficient number of microorganisms in a viable state inoculated to soil or seed to augment the nutrient availability to plant by enhancing the growth and proliferation of microorganisms.
Use of biofertilizers is one of the important components of integrated nutrient management, as they are cost effective and renewable source of plant nutrients to supplement the chemical fertilizers for sustainable agriculture This ppt is very essential & useful for vegetable crop production, because present time the farmers was used fertilizers is more compared to the recommended dose of fertilizer. so i can suggested the farmers use of bio fertilizer because they have farmers ecofriendly.
Sulfur is a chemical element with symbol S and atomic number 16 with atomic mass 32.065.
It is abundant, multivalent, brittle, yellow, tasteless, odourless and non-metallic element.
Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth.
In the Bible, sulfur is called brimstone .
Today, almost all elemental sulfur is produced as a by product of removing sulfur-containing contaminants from natural gas and petroleum.
Most soil sources of S are in the organic matter and therefore concentrated in the top soil or low layer.
Under normal conditions, sulfur atom forms cyclic octatomic molecules with a chemical formula S8.
Sulphur is the most abundent and widely distributed element in the nature and found both in free as well as combined states.
Microbial biomass in soil, measurement by chloroform fumigation incubation method, limits of measurement of microbial biomass, why microbes are important in the soil, why microbial biomass is important in the soil
Soils give a mechanical support to plants from which they extract nutrients. soil provides shelters for many animal types, from invertebrates such as worms and insects up to mammals like rabbits, moles, foxes and badgers. It also provides habitats colonised by a staggering variety of microorganisms. This module is about the microbial life in soils.
Effect of Aloe Vera wastes on physico-chemical properties and microbiological...IJEABJ
The aim of the present study was to explore the potential for using aloe vera wastes as amendment for soil to improve its fertility. Soil was exposed to four concentrations of aloin (rich in HAP) for 0, 7, 14 and 28 days. Physico-chemical parameters were analyzed: soil Ph, organic matter (OM), nitrogen, phosphorus, and cation exchange capacity (CEC). The activity of seven enzymes implicated in the C, N and S cycles were measured. Microbial Biomass was determined by the method of substrate induced respiration. BiologEcoplates (Biolog Inc., Hayward, CA) were used to estimate soil microbial functional diversity. Our findings suggested a decrease on phosphorus and nitrogen content and an increase on CEC after aloin addition. Also, a decrease on microbial biomass and enzymes activities was observed, except for FDA. Ecoplates results demonstrate a decrease on microbial activities depending on the incubation time. Moreover, our results indicated that bacterial communities of the tested soils have more affinity to consume substrates as Amino acids and polymers. Our results should be carefully considered in view of the agriculture waists reuse for a sustainable agriculture
Soil Health definition and relationship to soil biology
Characteristics of healthy soil
Assessment of soil health
Framework for evaluating soil health
Indicators
Types of indicators
Biological indicators
Role of biological indicators
The Role of Soil Organisms and Functions in different Coconut based Multiple ...Agriculture Journal IJOEAR
Abstract—Sampling was done in wet and intermediate zones represented by the Walpita and Makandura research centers, respectively. Eleven land use systems were considered for the study; coconut mono culture (CM), bare land (BL) and coconut multiple cropping. Under coconut multiple cropping, nine different intercrops were selected separately for each zones. The treatments were arranged in a randomized complete block design (RCBD) with three replicates (n = 3). The experiment was conducted under mature baring coconut (>20 years) plantation. Soil Macrofauna was sampled using one transect with three replicates at each land use type using quadrate size (30×30cm) from 0-30 cm depth and visible organisms were handpicked and preserved in 75% alcohol. Dilute plate technique and Spread plate technique was used to determine the soil micro organisms’ density. Those techniques were used to cultivate the fungi and bacteria under 〖10〗^(-2) and 〖10〗^(-5) dilution level respectively.
Research identified 12 classes (Crusteacea, Oligochaeta, Hirudinea, Gastropoda, Acarina, Araneida, Scopionida, Chilapoda, Diplopoda, Amphibia, Reptelia) and 14 orders (Hemiptera, Diptera, Coleoptera, Thysanura, Hymenoptera, Lepidotera, Orthoptera, Blattaria, Mantodea, Phasmida, Dermaptera, Isoptera, Siphonaptera, Thysanoptera) of soil organisms. Class insecta shows the high diversity with 14 orders. Colony forming unit (CFU) value of bacteria was higher than that of the fungi value. Findings of intermediate and wet zones’ studies suggested that coconut multiple cropping systems may have high diversity, abundance and functional role of soil organisms. Both zones studies suggested that coconut multiple cropping systems may increase soil moisture factor, respiration rate, biomass carbon content, organic carbon percentage, total nitrogen content, organic matter content and C:N ratio in 0-30cm depth other than the coconut monoculture systems. Overall data of two different zones indicated a significant positive correlation of soil organism diversity, abundance and their functional role with cropping systems. Those data can be used as a reliable basic bio indicator for payments for ecosystem services (PES). It supports to valorize the economic value of the ecological services returned by soil organisms.
Studies the Effects of Imidacloprid on Enzymatic Activities in Clay Loam Soilijtsrd
In-vivo experiment was conducted for toxicity evaluation of Imidacloprid on soil enzyme activities arylsulphatase, acid-phosphatase and dehydrogenase activities in the treated soil under control condition for 60 days at different application rate 3.97µg mL FR , 7.94µg mL 2FR and 39.7µg mL 10FR . Imidacloprid has significant toxic at 2FR and 10FR doses but not on the recommended field rate FR . Acid phosphatase activity was stimulated at FR rate, whereas at higher dose 10FR inhibited the activity. A significant drop of dehydrogenase activity was observed irrespective of doses at 30 days of application and after that the enzymatic activity slowly increased. Application of Imidacloprid at FR to agriculture soil of Tripura is not likely to show any detrimental effects on soil acid phosphatase and dehydrogenase activities but at higher elevated doses there appear some harmful effects which was also very much transient. Aloke Purkait | Dipak Kumar Hazra | Pabitra Kumar Biswas | Ashim Chowdhury "Studies the Effects of Imidacloprid on Enzymatic Activities in Clay Loam Soil" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-2 , February 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21406.pdf
Paper URL: https://www.ijtsrd.com/chemistry/analytical-chemistry/21406/studies-the-effects-of-imidacloprid-on-enzymatic-activities-in-clay-loam-soil/aloke-purkait
Seed management’s influences on nodulation and yield of improved variety of s...Agriculture Journal IJOEAR
Abstract— A pot study was carried out on an improved soybean variety (TGX 1448-2E) to assess the effects of seed management on its nodulation and yield. The experiment was in factorial combinations with six replicates at the teaching and research farm of University of Abuja. The factors were 2 soils, 2 levels of phosphorus fertilizer (-P and + P), and 2 seed sources (farmer’s and researcher’s managed seeds). P was applied as triple superphosphate at 30 kg P ha-1. Destructive sampling was done at 8 weeks after planting to record growth parameters and nodulation. At maturity, the number and weight of pods, weight of 50 seeds and total seed yield were recorded. The results showed that generally researchers’ managed seeds showed a significantly higher mean values than farmers’ managed seeds. The pod and total seed weight from researchers’ seeds were 106.26 g and 52.43 g per plant respectively against the farmers’ managed seed with pod weight of 80.23 g and total seed weight of 44.35 g per plant. P application influenced significantly the weight of nodules, pods and seeds per plant. This significant lower performance observed in farmers’ managed seeds could have resulted from factors such poor seed handling or mix up during harvesting or storage, poor quality seed selection for planting.
Presentation by Steve Diver from the 2012 Resilient Farmer Workshop at the Kerr Center's Cannon Horticulture Plots in Poteau, Oklahoma. Cover crops, soil organic matter, soil food web
Acceleration of Lead Phytostabilization by Maize (Zea mays) in Association wi...Agriculture Journal IJOEAR
Abstract— Soil where shooting practices are conducted is extremely contaminated with heavy metals, exclusively by Pb, due to the bullets and bullet fragments. These extreme concentrations of Pb, generate an unfavourable surroundings for agriculture and human health through phytoaccumulation. This study was conducted to assess the possibility of particular bio-amendment, phytostabilization on the reduction of bioavailable Pb in such contaminated soil. Biomass (BM) produced from Gliricidiasepium was used to see its ability to be used in soil remediation together with Maize (Zea mays) as phytostabilizer. A pot experiment was conducted with Maizeby adding BM at three different percentages, 1, 2.5 and 5% (w/w). Soil without amendments served as the control and arranged in a complete randomized design. By maize, translocation rate of heavy metals into crop were determined. After sixth week, grown maize were harvested and analyzed followed by digestion with con.HNO3. The most significant immobilization (p<0.05)>TF in maize. For the treatment 5% BM, PF and TF for Pb are 1.22 and 0.15 respectively. Thereby maize can be considered as a potential phytostabilizer. At the same time efficiency of phytostabilizing nature of maizecan increase together with the application of soil amendment – BM.
Yield potentials of recently released wheat varieties and advanced lines unde...Innspub Net
An experiment was conducted to study the varietals /genotypic potentiality in producing maximum yield under
different soil and environmental conditions and N-use efficiency of different genotypes and to support wheat
breeding program in selecting the genotype with relatively higher yield potential. The experiment was conducted
in split plot design with three replications to evaluate the two soil management practices: (i) Recommended
fertilizer (N100P30K50S20) with all the production package of Wheat Research Center (WRC) (timely sowing, one
weeding, 3 irrigations) (ii) Treatment (i) plus soil treatment (application of granular fungicide in moist soil before
seeding) with plant protection (foliar application of tilt at anthesis and grain filling). One additional irrigation
(schedules: 17-21, 35-40, 55-60, 75-80 DAS) in the main plot and eight varieties/lines, varities: i) Shatabdi ii)
Prodip iii) Bijoy iv) BARI Gom-25 v) BARI Gom-26, lines: vi) BAW 1051 vii) BAW 1135 and viii) BAW 1141 in subplot were adopted. The results conclude that best management practice with Prodip, Bijoy and BAW 1141 are best performance among the genotypes/varieties and will give a new concept on identification of the strategy for the improvement of wheat cultivation and yield.
A possible approach to control soil erosion: natural farmingExternalEvents
Ms Silvia Socciarelli, Council for Agricultural Research and Economics (CREA), Italy. Global Symposium on Soil Erosion (GSER19), 15 - 17 May 2019 at FAO HQ.
Climate Change All over the World .pptxsairaanwer024
Climate change refers to significant and lasting changes in the average weather patterns over periods ranging from decades to millions of years. It encompasses both global warming driven by human emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. While climate change is a natural phenomenon, human activities, particularly since the Industrial Revolution, have accelerated its pace and intensity
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Epcon is One of the World's leading Manufacturing Companies.EpconLP
Epcon is One of the World's leading Manufacturing Companies. With over 4000 installations worldwide, EPCON has been pioneering new techniques since 1977 that have become industry standards now. Founded in 1977, Epcon has grown from a one-man operation to a global leader in developing and manufacturing innovative air pollution control technology and industrial heating equipment.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
2. Speaker:
Pradip Tripura
Ph.D (Agri.) student
Reg. No. 1010115012
College of Agriculture
J.A.U., Junagadh.
Major advisor:
Dr. K. B. Polara
Professor
Dept. of Agril. Chemistry and
Soil Science
College of Agriculture,
JAU., Junagadh.
Minor advisor:
Dr. B. K. Sagarka
Professor and Head
Dept. of Agronomy
College of Agriculture,
JAU., Junagadh.
SEMINAR ON
Effect of soil management practices on soil
enzyme activities
2
3. 3
Soil enzymes - function, classification, sources, importance and
application
Soil enzyme as biological quality indicator
Role of soil enzymes in maintaining soil health
Different methods of enzyme activity measurement
Effect of different management practices on enzymatic activity
Conclusion
Contents
5. Soil Enzymes
A substance produced by a living organism which acts as a
catalyst to bring about a specific biochemical reaction.
A group of enzymes.
Inhabitate in soil.
Playing an important role in maintaining soil ecology, physical and
chemical properties, fertility, and soil health.
Functions of Enzymes in soil
Play key biochemical functions in the overall process of organic
matter decomposition in the soil system (Sinsabaugh et al., 1991)
Important in catalyzing several vital reactions necessary for,
Life processes of micro-organisms in soils.
The stabilization of soil structure.
Organic matter formation.
Nutrient cycling.
5
6. 1. Oxidoreductases - Oxidation reduction reaction
(Dehydrogenase, Catalase, Peroxidase)
2. Tranferases - The transfer of group of atoms from
donor to an acceptor molecule.
(Aminotransferases, Rhodonese)
3. Hydrolases - Hydrolitic cleavage of bonds.
(Phosphatase, Cellulase, Urease)
4. Lyases - Cleavage of bonds other than hydrolysis
or oxidation.
(Aldolase)
5. Isomerases - Isomarization reaction
6. Ligases - Formation of bonds by the cleavage of
ATP.
(Acetyl-CoA carboxylase)
Enzymes Classification
6
7. 1 Constitutive
Always present in nearly constant amounts in a
cell (not affected by addition of any particular
substrate – genes always expressed).
(Pyrophosphatase)
2 Inducible
Present only in trace amounts or not at all, but
quickly increases in concentration when its substrate
is present.
(Amidase)
Both types of enzymes are present in the soil.
Kind of soil Enzymes
7
8. Although the general origins of soil
enzymes are:-
(a) Microorganisms-living and dead
(b) Plant roots and plant residues and
(c) Soil animals;
Origin of soil Enzymes
8
9. State-1: Role of Clays
a. Most activity associated with clays.
b. Increases resistance to proteolysis and microbial attack
c. Increases the temperature of inactivation.
State-2 :Role of Organic Matter
a. Humus material provides stability to soil nitrogen
compounds
b. Enzymes attached to insoluble organic matrices exhibit pH
and temperature changes.
c. Inability to purify soil enzymes free of soil organic matter
(bound to O.M. )
State-3: Role of O.M. - Clay Complex
a. Lignin + bentonite ( clay ) protect enzymes against
proteolitic attack, but not bentonite alone.
b. Enzymes are bound to organic matter which is then bound
to clay.
State of soil Enzymes
9
10. 1. Accumulated enzymes
2. Continuously released extracellular enzymes
Proliferating
microbes
Plant roots Soil faunaBound to
microbial cells
Not associated with
Cellular components
Non
proliferating
cells
Dead cells Cellular
fragments
Originating
from plant
roots
Originating
from
microbes
and soil
fauna
Microbes Plants
Dick and Tabatabai (1992)10
11. Importance of Soil Enzymes
Release of nutrients into the soil by means of organic matter
decomposition.
Identification of microbial activity.
As sensitive indicators of ecological change.
Application of Soil Enzymes
Correlation with soil fertility
Correlation with microbial activity
Correlation with biochemical cycling of various elements in soil
(C, N, S)
Degree of pollution (heavy metals, SO4)
To assess the successional stages of an ecosystem
Rapid degradation of pesticides
Disease studies
Enzyme activity as biological indicator of soil health and quality
and monitoring soil quality improvement
11
12. Soil enzymes as biological soil quality indicator
Soil Quality:
Capacity of a specific kind of soil to function within ecosystem and landuse
boundaries, to sustain biological productivity, maintain environmental quality and
sustain plant, animal and human health (Doran and Parkin, 1994)
Soil health:
A state of dynamic equilibrium between flora and fauna and their sourrounding soil
environment in which all the metabolic activities of the former proceed optimally
without any hinderance, stress or impedence from the later (Goswami and Rattan,
1992)
The definition of soil quality encompasses physical, chemical and biological
characteristics, and it is related to fertility and soil health
Biological indicators of soil quality:
Properties associated with biological activity on organic matter, such as
A. Microbial biomass carbon
B. Soil respiration
C. Abundance, diversity, food chains and stability of microbial communities
D. Mesofauna such as earthworms, nematodes and arthropods
E. Biological activities such as enzyme activity
F. Potentially mineralized nitrogen
G. CO2 production
12
13. Cont….
Why soil enzymes are considered as useful indicators of
soil quality?
Soil enzyme activities,
(1)Closely related to soil organic matter, soil physical
properties and microbial activity or biomass
(2)Changes much sooner than other parameters, thus
providing early indications of changes in soil health
(3)Involve simple procedures for determination of activity
(Dick et al., 1996)
13
14. Soil Enzyme Enzyme reaction End Product Indicator of
microbial activity
ß glucosidase Cellobiose hydrolysis Glucose C Cycling
FDA hydrolysis Organic matter
decomposition
Different nurients C Cycling
Amidase N-mineralization Ammonium N Cycling
Urease Urea hydrolysis Ammonium N Cycling
Phosphatase Hydrolysis of organic P
compounds
Inorganic Phosphate P Cycling
Arylsulphatase Hydrolysis of organic S
compounds
Inorganic Sulphate S Cycling
Phenol oxidase Lignin hydrolysis Low molecular
weight C
compounds
C Cycling
Cellulase Cellulose hydrolysis Glucose C Cycling
Dehydrogenase Electron transport
system
Oxidized products C Cycling
Potential Roles of Soil Enzymes in Maintaining Soil Health
14
15. Approach I :
Two methods are used frequently. These are,
Colorimetric assay – By using p-nitrophenol (pNP) linked substrates or L- 3, 4-
dihydroxyphenylalanine (L-DOPA) or 2,3,5 triphenyl tetrazolium chloride (TTC)
Fluorometric assay – By using 4-methyl umbelliferone (MUF) or 7-amino-4-
methyl coumarin (AMC) linked-substrates.
Different methods of enzyme activity measurement
Approach I I :
In situ approach. Include, addition of varying concentration of a single substrate with
the intention of having non-limiting substrate and, thereby, measuring Vmax as a proxy
for enzyme pools from the Michaelis-Menten equation.
Approach III :
Genomic tools - Allow us to determine the genetic potential for the production
of specific enzymes in complex microbial communities
Transcriptomic tools - Enable us to examine controls on the expression of
enzyme coding genes
Proteomic methods - Allow us to directly detect the presence of enzymes in
the environment as well as providing information about the organisms that produce
them
15
16. Land use changes
Soil amendments - lime and
gypsum addition
Conservation practices
Tillage and cultivation
Soil Management
Practices
Crop rotation
Irrigation practices
Soil management practices affecting enzyme activities
LTFE with INM
Pesticide
application
16
18. CCCC - continuous corn
CSbCSb - corn–soybean
CCOM - corn–corn–oats–
meadow (alfalfa)
SbSbSbSb - continuous
soybean
Fig-1. Impacts of crop rotations on urease activity
18Lowa state university, USA Klose andTabatabai (2000)
19. CCCC - continuous corn
CSbCSb - corn–soybean
CCOM - corn–corn–oats–meadow (alfalfa)
SbSbSbSb - continuous soybean
Klose et al. (1999)
Fig – 2. Impact of crop rotation on arylsulphatase activity
19Lowa state university, USA Klose andTabatabai (2000)
20. Fig - 3. application of organic and inorganic nutrients to a Maize–Wheat rotation
on soil dehydrogenase activity
20Uttarakhand Saha et al. (2008)
21. Fig – 4. Effects of different tillage and crop rotation treatments on enzyme activity
RT-CC ridge tillage with monoculture
corn, RT-CS ridge tillage with corn-
soybean rotation, NT-CC no-tillage with
monoculture corn, NT-CS no-tillage with
corn-soybean rotation
21China Zhang et al. (2014)
23. Study site - Nokrek Biosphere Reserve in the western part of
Meghalaya, north-east India.
Two zones of Jhum cultivation :
a) Buffer zone – Exposing different degrees of jhum fallows of
different ages (1, 3-4, 6-8 and 12 years)
b) Core zone – Undisturbed forest
About 129 villages of the Garo tribe with a total population of
39,432 are located in the buffer zone.
Shifting agriculture is extensively practiced by these people in
the entire buffer zone.
This agricultural practice involves slashing or complete clearing
of the vegetation and burning of dried slash during dry winter,
followed by pure and mixed cropping.
Effect of shifting cultivation on enzyme activities
23Meghalaya Ralte et al. (2005)
24. Fig – 5. Impacts of shifting cultivation on dehydrogenase activity
TPFreleased(µg/g/24hr)
0-10 cm
10-20 cm
Ralte et al. (2005) 24
Meghalaya Ralte et al. (2005)
C - Primary forest,J12, J6, J3 and J1 = 10-12, 6-8, 3-4 and 1 year
jhum fallows
25. Fig – 6. Impacts of shifting cultivation on urease activity
NH4released(µg/1oog/6hr)
10-20 cm
Ralte et al. (2005)
The increase in dehydrogenase and urease activities from the young to the
old jhum fallows may be attributed to the build up of organic matter and
nutrients in the soil.
25Meghalaya Ralte et al. (2005)
26. Effect of soil amendment addition on
enzyme activities
26
27. Experimental Site : Northeast
Research Center in Nashua,
Iowa.
Soil samples collected from
0- 15 cm surface soil after 17
years of lime application in the
form of CaCO3
Fig – 7. Effect of lime application on soil phosphatases activity
27USA Acosta-Martinez and Tabatabai (2000)
28. control
N
Lime
N+Lime
Fig – 8. Effect of liming and nitrogen fertilization on soil phosphomonoesterase
activity
Johnson et al. (2005)
28University of Sheffield, UK Johnson et al. (2005)
29. Fig – 9. Enzyme activity assay in different soil amendments
X axis - 1.rhizosphere soil, 2.fungicide treatment, 3.insecticide treatment, 4.biofertilizer
treatment, 5.bulk soil; y axis optical density
29Kerala Aswathy and Jose (2013)
31. 31
Fig – 10. Effect of land use types on soil enzymatic activities
Bamako (Mali) Gonnety et al. (2012)
32. Fig – 11. Phytase activity of arid crops was grown under tillage and
no-tillage condition
32Rajasthan Yadav and Tarafdar (2004)
33. Arylsulfatse activities of fodder, organic farming and soybean-wheat
systems were found to be at par.
If season and depths are compared, the arylsulfatase activity in the 0-15
cm soil depth can be arranged as: forest >soybean-wheat ≈ fodder ≈
organic farming > barren land
Fig – 12. Effect of land use changes on enzyme activities in the
himalayan region
33
IARI, New Delhi Justin et al. (2013)
34. Enzyme activities as
affected by soil order.
Enzyme activities as
affected by land use.
Fig – 13. Enzymatic activity affected by land order and land use
34
Akron, United state Acosta-Martinezn et al. (2007)
35. Table -1. Impact of land use system on enzymatic activity in central
Himalayan region
35IARI, New Delhi Singh et al. (2014)
37. 37
Treatment
Dehydrogenase Activity
(μg TPF-1 24 hr-1 g-1 soil)
1st Year 12th Year
T1 (50 % NPK of recommended dose of Groundnut-Wheat sequence) 36.5 26.5
T2 (100% NPK of recommended dose of Groundnut-Wheat sequence.) 42.5 32.5
T3(150% NPK of recommended dose of Groundnut-Wheat sequence) 30.0 30.5
T4(100% NPK+ ZnSO4 @ 50 kg/ha once in three year to groundnut only.) 46.5 31.5
T5(NPK as per soil test) 33.5 22.5
T6(100% NP of recommended dose of Groundnut-Wheat sequence) 38.3 33.5
T7(100% N of recommended dose of Groundnut-Wheat sequence) 46.5 36.5
T8(50% NPK + FYM @ 10 t/ha to Groundnut and 100% NPK to wheat) 52.5 42.5
T9(Only FYM @ 25 t/ha to Groundnut only) 49.5 35.5
T10(50% NPK + Rhizobium + PSM to groundnut and 100 % NPK to wheat) 31.5 21.5
T11(100% NPK of recommended dose of Groundnut-Wheat sequence. (P as
SSP)
40.5 28.5
T12 (Control) 29.5 19.5
MEAN 39.7 30.0
S.Em.± 2.3 1.5
C.D. at 5 % 6.6 4.4
C.V. % 11.5 10.3
Table 2. Effect of different treatment on Dehydrogenase Activity in 1st and 12th
Year of LTFE Soils.
JAU, Junagadh Karad et al. (2016)
38. Fig – 14. Impact of long-term organic and inorganic nutrient Managements on
enzyme activities
Long-term nutrient experiment in semi-arid Alfisol at Coimbatore.
investigated in two successive years, 2009 and 2010 to assess the effects of
organic manure (OM) and inorganic chemical fertilizers (IC) on phosphatase
activities.
38Tamilnadu Chinnadurai et al. (2014)
39. For improving N supply and
management in Rice Wheat
Cropping system Sesbania
sesban and the nitrification
inhibitor encapsulated calcium
carbide (ECC) is used widely.
Fig – 15. Effect of green manure and nitrification inhibitor on DHA and Nrse activity
Patra et al. (2006) 39IARI, New Delhi Patra et al. (2006)
40. Fig – 16. Enzymatic activity in soil with different treatment in LTFE soil under a
rainfed soybean–wheat system in N-W Himalaya.
Saha et al. (2008)
40Uttarakhand Saha et al. (2008)
41. Fig – 17. Effect of LTFE on enzymatic activity under a rainfed soybean–wheat
system in N-W Himalaya
Saha et al. (2008)
41Uttarakhand Saha et al. (2008)
43. What is enzyme kinetics ?
Enzyme kinetics refers in terms of rate at which substrate is
converting into product.
What is utility of studying enzyme kinetics ?
To know the efficiency of enzymes kinetic study is needed.
How to study enzyme kinetics ?
To know the efficiency of enzymes we should know various
parameters. These parameters comes from the well known
Michaelis-Menten equation :
V= (Vmax × S) / (Km + S)
Where, V=Enzyme activity, Vmax = Maximum velocity of enzyme
reaction, S=Substrate concentration (p-NPP), Km = Michaelis-
Menten constant
Vmax and Km are called kinetic parameters.
Km is the substrate conc at which Vmax decreases to its half, which
tells us the affinity of enzyme for substrate and is inversely
proportional to the substrate affinity. i.e lesser the value of the Km,
more will be the affinity of enzyme for substrate.
43
44. Fig – 18. Kinetic parameters as affected by Tillage and no tillage practices
Surface (0-20 cm) meadow brown
soil samples collected from the
plots under no tillage and
conventional tillage in a 7-year
field experiment under maize
cropping.
Higher Vmax value for Pase, Pdse
and Arase in NT system than CT
system.
Lower Km value for Pase, Pdse
and Arase in NT system than CT
system.
For urease reverse is true.
44China Zhang et al. (2010)
45. Fig 19. Kinetic parameters as affected by vermicompost and fertilizers addition
0
1
2
3
4
5
6
7
8
9
10
Control VC VC + Fert Fert
Km (mM)
Vmax
(nmol/g/hr)
b
c
b
a
b b
b
a
a
c c
a
Vmax increases markedly in organic and organomineral
treatments.
Km was similar in vericompost treated soil and control soil
while doubled in organomineral and mineral treatments.
45Pisa, Italy Masciandaro et al. (2000)
47. Effect of pesticides on soil enzymes
Pesticides reaching the soil may disturb local metabolism or
enzymatic activities.
Negative impact of pesticides on soil enzymes like hydrolases,
oxidoreductases, and dehydrogenase activities has been widely
reported in the literature. (Malkomes, 1989; Menon et al., 2005)
There is also evidence that soil enzymatic activities increased
by some pesticides (Megharaj et al., 1999)
The effect of pesticides on soil enzymes particularly
extracellular enzymes are not clear due to their
multidimensional behaviour in complex soil medium and the
greater complexity of soil microbial and biochemical
interactions
47
48. A. Dehydrogenase activity
B. Phosphatase activity
Fig – 20. Effect of different concentration of butachlor on DHA and Ptse activities
Un-flooded
Un-flooded Flooded
Flooded
N (23 mg kg-1), N10 (230 mg kg-1) and N100 (23 g kg-1) at -10 cm depth of soil
48
Srinagar, J & K Rasool et al. (2014)
49. Protease :- *μg glucose per gram soil formed after 24 hrs with 1% casein.
Urease :- *μg glucose per gram soil formed after 24 and 72 hrs incubation with 2% starch.
Figures in parentheses indicate relative production percentages.
Table – 3. Effect of different concentrations of selected insecticides on Protease
and Urease activity
49
Kurnool district, AP
Protease Urease
Nasreen et al. (2012)
50. Fig – 21. Effect of pesticide on enzymatic activity under biochar - amended soil
S- control,
SBC30- biochar amended soil – 30kg/ha,
SBC40 -biochar amended soil – 45kg/ha,
50Poland Olesczuk et al. (2014)
51. Dehydrogenase activity was highest in the non-Bt treatment
followed by Bt-cotton and least in the no-crop treatment.
It also varied significantly between the four sampling times.
51
Table - 4. Dehydrogenase activity in the rhizosphere soils under Bt(BT) and
non-Bt(NBT) cotton crops.
IARI, New Delhi Sarkar et al. (2008)
NC indicate no crop.
53. Treatments
Tillage
No of Irrigation
Conservation Conventional
2
(sub opt)
3
(optimal)
5
(supra opt)
2
(sub opt)
3
(optimal)
5
(supra opt)
T0 139.1b 142.3a 91.3a 73.4a 70.3a 65.1
T1 158.3d 231.5c 172.6b 84.4b 115.6c 87.2b
T2 262.9e 292.5c 166.5d 112.3c 93.7d 82.5c
T3 178.4c 162.6b 112.3b 93.6b 102.4a 106.3a
T4 277.7d 233.2b 211.4a 131.3c 98.9b 152.4c
T5 251.3c 158.7b 131.6e 121.7b 95.6b 121.6b
T6 310.3f 351.1d 236.7a 152.4d 127.4d 163.7d
T7 111.4a 114.4a 152.3a 62.2d 68.7b 75.4a
Urease activities in terms of µg NH4 released /g soil/hr
T0 = No external Fertilizer
T1 = Recommended dose of N (RDN) through urea
T2 = 75% RDN urea + 25% RDN FYM
T3 = 75% RDN urea + 25% RDN GM
T4 = 75% RDN urea + 25% RDN BF
T5 = 75% RDN urea + 25% RDN SS
T6 = 50% RDN FYM + 25% RDN BF + 25% RDN GM
T7 = Blank Plot
Table – 5. Effect of Conservation tillage, optimal Water supply and INM
on urease activity
53IARI, New Delhi Sharma et al. (2013)
54. Fig – 22. Effect of cover crops on arylamidase activity at different depths in
conventional tillage and no-till systems.
54Tuskegee University, United state Said et al. (2009)
arylamidase
55. Fig – 23. Effect of zero tilled and tilled on soil enzyme activities at different depth
surface (0 - 10 cm) and subsurface (10 - 20 cm) layers
55East Midlands, UK Mangalaserry et al. (2015)
56. Fig – 24. Soil phosphatase activities under no-tillage and tillage at different
residue input amounts
Wang et al. (2011)
TR0, TR50, and TR100 are conventional tillage with 0, 50, and 100% residue input
amounts. NTR0, NTR50, and NTR100 are no-till with 0, 50, and 100% residue input
amounts, respectively
56China Wang et al. (2011)
58. 58
Fig – 25. Effects of irrigation induced salinity and sodicity on phosphatase
activities
Zimbabwean Rietz and Haynes (2003)
59. 59
Fig – 26. Effects of irrigation induced salinity and sodicity on arylsulphatase
activities
Zimbabwean Rietz and Haynes (2003)
60. Groundwater (GW), and River water (RW), Sensitive Index (SI) Catalase activity (CAT),
dehydrogenase (DEH), alkaline phosphatase (ALP), β-glucosidase (GLU), arylsulphatase (ARY)
and urease (URE) activities
The sensitive index (SI) related to irrigation treatments for labile organic Carbon fractions
and enzyme activity was calculated using the following equation:
mean of RW irrigated value – mean of GW irrigated value
mean of GW irrigated value
Table – 6. Effect of Different sources of irrigation on enzyme activities of
soil
60China Gao et al. (2015)
GLU URE ALP ARY DEH CAT
Sep 2012
GW 71.8 153.1 399.2 34.5 142.7 0.58
RW 116.4 213.0 496.6 52.1 202.1 0.67
SI 62.1 39.1 24.4 51.0 41.6 14.9
May 2013
GW 74.2 161.1 418.3 35.7 157.4 0.65
RW 134.6 235.9 532.6 69.5 223.4 0.71
SI 81.4 46.4 27.3 95.0 41.9 8.8
Mean
GW 73.0 157.1 408.8 35.1 150.0 0.62
RW 125.5 224.4 514.6 60.8 212.7 0.69
SI 71.9 42.9 25.9 73.3 41.8 11.7
SI = ×100
61. Fig – 27. Effect of long term irrigation on the profile distribution of
enzyme activity of typical chernozem soil
61Republic of Moldova Senikovskaya and Filipchiuk (2011)
62. Conclusions
crop rotation greatly influences the enzyme activities such as
urease, arylsulphatase, dehydrogenase etc. in soil.
Long term application of compost and/or FYM along with NPK
resulted in stimulation of all types of enzyme activities.
soil mulching enhances the phosphatase and aryasulphatase
activity.
lime application in acid soil has favorable effect on the activity
of alkaline phosphatase.
Organic farming system has improved kinetic properties (in
terms of Vmax) than conventional one but Km remain
unchanged.
62
Soil enzyme activities is critically important for Soil quality that can provide basic indications for changes in metabolic capacity and nutrient cycling due to management practices
The total, intracellular, and extracellular urease activities in soils of the Iowa at the Northeast Research Center site were significantly affected by crop rotations, but not by N fertilization.
Highest urease activity values were found in soils under the 4-year corn–oats–meadow rotations (CCOM) under the 0 N treatment. The lowest activities were obtained in soils under continuous cropping systems (CCCC, SbSbSbSb).
These results indicate that the type of crop rotation had little influence on the state of urease activity in soils, because the intracellular and extracellular activities were enhanced by more diverse crop rotations proportionately.
All pools of arylsulfatase activity in soils were significantly affected by crop rotation and plant cover at sampling time, but not by N fertilization.
The higher arylsulfatase activities in soils under cereal-meadow rotations compared to CCCC or soybean systems may have been due to the positive effects of diversified crop rotations, im-proved soil structure, nearly year-round rhizosphere and plant cover, stabilized microclimate, and higher root density.
Seasonal change as well as change of enz activities due to varying periods of fallowing were studied.
DHA activity min during winter and max durug autumn.
In the case of jhum fallows, it increased from the 1 to 10–12 years old fallow during winter (January), spring (March) and rainy (August) seasons.
The steady increase in dehydrogenase and urease activities from the young to the old regrowth on jhum fallows may be attributed to the build up of organic matter and nutrients in the soil.
liming increased the ac-tivities of the alkaline phosphatase and phosphodiesterase.
Levels of Pac and Pal activity, in particular, were higher than those of
NAG and β-Glu and there were significant differences between land-use types in enzymatic activity levels. cumulative enzymatic activities were higher in fallow than in the other types of land uses. Except for fallow enzymatic activities generally decreased with increasing anthropogenic activities.
Results showed large variation in phytase activities of different plant rhizosphere and the rhizosphere activity was increased compared to fallow soils.
Neem, Azadirachta indica, had highest phytase activity among the trees, and sewan grass,Lasiurus sindicus, resulted in more activity among grasses.
Phytase released in different plant rhizospheres had different temperature optima.
Green manure Sesbania sesban(S. sesban) and the nitrification inhibitor encapsulated calcium carbide (ECC) have been used
to improve N supply and management in rice–wheat production systems in India. However, the ecological impact of combined use of these materials should known
In this study, soils receiving applications of urea (S1) and urea +S. sesban(S2) had similar dehydrogenase activities but this was greatly reduced by application of ECC (seeS3 and S4 inFig. 2). This indicates that apart from nitrification inhibitory property of ECC, it has potential to inhibit the activities of other organisms in soil.
Vmax, which represents a measurement of the quantity of enzyme, markedly increased in organic and organo-mineral treatments, indicating that the addition of organic matter caused an increase in dehydrogenase in the active microbial biomass.
Km was similar in VC-treated soil and control soil, while it doubled in organo-mineral and mineral treatments. These results suggest that the use of VC did not alter the enzyme-substrate affinity, while mineral fertiliser reduced this affinity or changed the composi-tion and activity of soil microbiota.
Dehydrogenase activity (Table 2) was highest in the non-Bt treatment followed by Bt-cotton and least in the no-crop treatment. It also varied signifi-cantly between the four sampling times
Lower dehydrogenase activity in the Bt-system indicates that a portion of the organisms was perhaps inhibited and did not participate in the metabolic activities of the soil (Masto et al. 2006). It may have been partly because of unfavourable conditions in the rhizosphere under Bt-cotton or because of a negative effect of Bt-toxins on certain microbial groups, which might have retarded metabolic activities in the soil.