Microbiology of green manuring how the microbes decomposed the organic manure after incorporation into the soil

1. Sunil Bhardwaj
Presentation topic:
“MICROBIOLOGY OF GREEN MANURING AND
ITS APPLICATION IN CROP PRODUCTION”

2. What is green manuring:
 It is the practice of growing lush plants on the site into
which you want to incorporate organic matter into
the soil while it is still fresh.
 Generally the practice of green manuring is adopted in
two ways-
1. In-situ green manuring
2. Green leaf manuring

3.  IN SITU GREEN MANURING:
 When green manure crops are grown in the field itself either as a
pure crop or as inter crop with the main crop and buried in the same
field, it is known as Green Manuring In-situ.
Ex: sun hemp, diancha, pillipesara, cowpea, Berseem, senji etc.
 GREEN LEAF MANURING:
 Application of green leaves and twigs of trees, shrubs and herbs
collected from elsewhere is known as Green Leaf Manuring.
Ex: Neem, Mahua, wild indigo, Calotropis, Subabul and other
Shrubs.

6. Objective of green manuring:
• The objective is to add an organic matter
into the soil and thus, enrich it with ‘N’
which is most important and deficient
nutrient.

7. Characteristics of good manuring:
 Plants should be fleshy and soft
 Fast growing
 Fast decomposing
 Leguminous
 Should’t attract pests and diseases
 Should’t compete with main crops
 Provide nutrients needed in the soil.

8. Time of green manuring-
• Mostly practiced in kharif season.
• High temperature help in rapid decomposition.
• Six weeks usually required to complete
decomposition.
• Usually done 6-8 weeks after sowing of green
manure crops, just before the flowering stage.

9. Effect of green manuring:
• Increases soil fertility.
• Develops soil structure.
• Enhances organic matter in the soil.
• Play an important role in reclamation of saline
and alkaline soils.
• Increases WHC

10. Microbiological processes in green
manuring
• The organic materials (plant and animal residues)
incorporated in the soil are attacked by a variety
of microbes, worms and insects in the soil if the
soil is moist.
• Some of the constituents are decomposed very
rapidly, some less readily, and others very slowly.

12. The list of constituents in terms of ease
of decomposition:
1. Sugars, starches and simple proteins- Rapid
Decomposition
2. Crude proteins
3. Hemicelluloses
4. Cellulose
5. Fats, waxes, resins
6. Lignins Very slow Decomposition

13. Conversion of Nitrogen in soil
It involves,
• 1. Ammonification
• 2. Nitrification
• 3. Denitrification

14. Ammonification:
• The transformation of organic nitrogenous
compounds (amino acids, amides, ammonium
compounds, nitrates etc.) into ammonia is called
AMMONIFICATION.
• This process occurs as a result of hydrolytic and
oxidative enzymatic reaction under aerobic
conditions by heterotrophic microbes.

15. Nitrification:
• The process of conversion of ammonia to nitrites (NO2) and then to
nitrate (NO3) is known as NITRIFICATION.
• It is an aerobic process by autotrophic bacteria.
Nitrosomonas Nitrobacter
NH3 --------------> NO2 ---------->NO3
Ammonia Nitrite Nitrate

16. Denitrification:
• The process, which involves conversion of soil
nitrate into gaseous nitrogen or nitrous oxide,
is called denitrification.
• Water logging and high PH will increase n loss
by denitrification.
pseudomonas / bacillus
nitrate --------------------> nitrogen gas

17. Decomposition of Insoluble
Substances-
• i) Breakdown of Protein: During the course of
decomposition of plant materials, the proteins are first
hydrolyzed to a number of intermediate products
Hydrolysis Proteases
Proteins ------>Peptones ------> Amides ---->Ammonia

18. ii) Breakdown of cellulose:
hydrolysis hydrolysis
Cellulose--------> Cellobiose -------Glucose
(cellulase) (cellobiase)
oxidation
-------> Organic acids ------> CO2 + H2O

19. iii) Breakdown of Hemicellulose:
• Decompose faster than cellulose and are first hydrolyzed to
their components sugars and uronic acids.
• Sugars are attacked by microbes and are converted to
organic acids, alcohols, carbon dioxide and water.
• The uronic acids are broken down to pentose and CO2.
• The newly synthesized hemicelluloses thus form a part of
the humus.

20. iv) Breakdown of Starch:
• It is chemically a glucose polymer and is first
hydrolyzed to maltose by the action of amylases.
• Maltose is next converted to glucose by maltase.
The process is represented as under:
(C6H10O5)n +nH2O --------> (C6H12O6)

21. C. Decomposition of ether soluble substances:
• Fats -----------> glycerol + fatty acids
• Glycerol -----------> CO2 + water
D. Decomposition of lignin: Lignin decomposes slowly,
much slower than cellulose. Complete oxidation gives
rise to CO2 and H2O.

22. Environmental factors affecting
decomposition:
1. Oxygen: aerobic and anaerobic
decomposition
2. Moisture :amount of moisture should be as
high as possible
• " Green manure", such as lawn clipping and
vegetable trimming are able to hold 50 to 60
percent moisture.

23. • Termperature :Temperature is an important
factor in the biological degradation
• winter months slow the decomposition process
• three categories
• Psychrophiles < 10*C
• mesospheric, those that live and grow in
temperatures of 50 °F to 113 °F (10 °C to 45 °C),
• thermophillic those that thrive in temperatures
of 113 °F to 158 °F (45 °C to 70 °C).

24. Importance in crop production-
• Green manure crops contributes 40-80 kg of N per ha.
• Along with nitrogen supply, it prevents loss of nitrogen by
leaching and erosion.
• Vigorous root system of green manure keeps the soil
particles bound together.
• Green manure reclaims saline and alkaline soils.
• Some green leaf manure crops serves as fodder.
• The growth of green manure crops is very fast.

25. • It adds organic matter to the soil and stimulates activity
of soil micro-organisms.
• It improves the soil structure there by improving the
WHC of soil.
• Decreases run-off and soil erosion caused by the rain.
• Green manures cover the ground and so reduces the
work and cost of weeding.
• There by, the usage of green manure will increases the
farm production.

26. BACTERIA FUNGI ACTINOMYCETES
CELLULOSE
DECOMPOSERS:
Bacillus,
Cellulomonas,
Achromobacter.
Pencillium,
Aspergillus.
Streptomyces,
Micromonaspora.
HEMICELLULOSE
Pseudomonas,
Bacillus,
Micrococcus,
Clostridia.
Aspergillus,
Fusarium,
Streptomyces,
Micromonaspora,
Nocardia.
PECTIN
Bacillus,
Clostridium.
Fusarium,
Verticillium.
Streptomyces.
LIGNIN
Pleurotus,
Agaricus,
Ganoderma.
Bacillus,
Pseudomonas,
Chromobacteria.
Aspergillus,
Fusarium,
Rhizopus.
Streptomyces,
Micromonaspora,
Nocardia

28. Thank you