IT IS A VERY GOOD PROJECT FOR MODERN AGRICULTURE.

1. Submitted By
Ramyajit Mondal
B.Sc(Ag.) Hons.,
7th Semester
Palli Siksha Bhavana
VISVA -BHARATI
ROLE OF SOIL ORGANIC MANURE
IN SUSTAINING SOIL HEALTH
Submitted To
Dr. N.C.Sarkar

2. 1
INTRODUCTION
Soils are dynamic ecosystems that support a diversity of life. Therefore, the concept
of soil health, like that of human health, is not difficult to understand or recognize when
the system is viewed as a whole. The challenge is to manage soils such that they are able
to perform the various uses they are put to without degradation of the soils themselves or
the environment.
The use of chemical fertilizers is increasing day by day for the sake of increasing
production. By excess use of chemical fertilizers, the fertility of soil and health also
deteriorate. Therefore the use of organic manure is one of the alternative ways for
enhancing production and improves the soil health. It is not only cheaper, easily available
and enhances agriculture too. Organic manures are natural products used by farmers to
enhance sustainable crop production. Organic manure increase organic matter in soil,
enables soil to hold more water and also helps to improve drainage in clay soil. Organic
manure increase to plant nutrient in soil. Thus organic manures helps in sustainable and
economic food production as well as sustainable agriculture.
DEFINITION OF SOIL HEALTH
Doran and Parkin (in Doran et al., 1994) defined soil quality (health) as “the
capacity of a soil to function, within ecosystem and land use boundaries, to sustain
biological productivity, maintain environmental quality, and promote plant and animal
health.” It is worth noting here that “soil health” and “soil quality” are essentially
synonymous terms.
Soil organic matter is natural source of plant nutrients. Organic matter makes a soil
healthy, a healthy soil produces a crop healthy, and healthy crops nourish people well.
This article discusses little about role of organic matter in soil health.
Soil Organic Matter
Organic material is anything that was alive and is now in or on the soil. Organic
material is unstable in the soil, changing form and mass readily as it decomposes. As much
as 90 percent of it disappears quickly because of decomposition. For it to become organic
matter, it must be decomposed into humus. In its broadest sense, soil organic matter
comprises all living soil organisms and all the remains of previous living organisms in their
various degrees of decomposition. Soil organic matter consists of a variety of components.
These include, in varying proportions and many intermediate stages, an active organic
fraction including micro-organisms (10–40 percent), and resistant or stable organic matter
(40–60 percent), also referred to as humus. The living organisms can be animals, plants or

3. 2
micro-organisms, and can range in size from small animals to single cell bacteria only a few
microns long.
Non-living organic matter can be considered to exist in four distinct pools:
 Organic matter dissolved in soil water
 Particulate organic matter ranging from recently added plant and animal debris to
partially decomposed material less than 50 microns in size, but all with an
identifiable cell structure.
 Particulate organic matter can constitute from a few percent up to 25% of the total
organic matter in a soil
 Humus which comprises both organic molecules of identifiable structure like
proteins and cellulose, and molecules with no identifiable structure (humic and
fulvic acids and humin) but which have reactive regions which allow the molecule
to bond with other mineral and organic soil components. These molecules are
moderate to large in size (molecular weights of 20,000 – 100,000). Humus usually
represents the largest pool of soil organic matter, comprising over 50% of the total.
NATURAL FACTORS INFLUENCING THE AMOUNT
OF ORGANIC MATTER & SOIL HEALTH
The transformation and movement of materials within soil organic matter pools is
a dynamic process influenced by climate, soil type, and vegetation and soil organisms. All
these factors operate within a hierarchical spatial scale. Soil organisms are responsible for
the decay and cycling of both macronutrients and micronutrients, and their activity affects
the structure, tilth and productivity of the soil.
 SALINITY AND ACIDITY -Salinity, toxicity and extremes in soil pH (acid or
alkaline) result in poor biomass production and, thus in reduced additions of organic
matter to the soil. For example, pH affects humus formation in two ways:
decomposition, and biomass production. In strongly acid or highly alkaline soils,
the growing conditions for micro-organisms are poor, resulting in low levels of
biological oxidation of organic matter. Soil acidity also influences the availability of
plant nutrients and thus regulates indirectly biomass production and the available
food for soil biota. Fungi are less sensitive than bacteria to acid soil conditions.
 VEGETATION AND BIOMASS PRODUCTION-The rate of soil organic
matter accumulation depends largely on the quantity and quality of organic matter

4. 3
input. Under tropical conditions, applications of readily degradable materials with
low C:N ratios, such as green manure and leguminous cover crops, favour
decomposition and a short-term increase in the labile nitrogen pool during the
growing season. On the other hand, applications of plant materials with both large
C:N ratios and lignin contents such as cereal straw and grasses generally favour
nutrient immobilization, organic matter accumulation and humus formation, with
increased potential for improved soil structure development.
 SOIL MOISTURE AND WATER SATURATION- Soil organic matter levels
commonly increase as mean annual precipitation increases. Conditions of elevated
levels of soil moisture result in greater biomass production, which provides more
residues, and thus more potential food for soil biota.
 SOIL TEXTURE Soil organic matter tends to increase as the clay content increases.
This increase depends on two mechanisms. First, bonds between the surface of clay
particles and organic matter retard the decomposition process. Second, soils with
higher clay content increase the potential for aggregate formation. Macro
aggregates physically protect organic matter molecules from further mineralization
caused by microbial attack
 TOPOGRAPHY Organic matter accumulation is often favoured at the bottom of
hills. There are two reasons for this accumulation: conditions are wetter than at
mid- or upper-slope positions, and organic matter is transported to the lowest point
in the landscape through runoff and erosion. Similarly, soil organic matter levels are
higher on northfacing slopes (in the Northern Hemisphere) compared with south-
facing slopes (and the other way around in the Southern Hemisphere) because
temperatures are lower.
 MICROBIAL POPULATION This effects the soil health very much.it helps in
mineralization process in which the nutrients become available to the plants. If there
is low amount of microbes then this should be consider as low quality soil.
 SOIL EROSION Soil erosion degrades the soil quality as well as soil health very
much. As in this process the fertile top soil is degraded and affect the organic matter
content.
 DEFORESTATION For urbanization the forest area is gradually decreasing. It a
one of the reason of degrading organic matter as well as its health.

5. 4
 LONG TERM EFFECT OF PESTICIDES AND CHEMICAL FERTILIZERS-
due to application of rapid pesticides and chemical fertilizers there is residue present
in soil which affects soil health.
 LONG TERM EFFECT OF THE TILLAGE It is detrimental for soil health and
soil quality.
 SELECTION OF CROP AND CULTIVARS selection of crops influence the
soil health as well as the organic matter. Different crops has the different
type of root system i.e. deep and shallow rooted crops which take
nutrients from different layers of soil. Thus if we practice proper crop
rotation then the health of soil can be maintained properly. Cultivation
of the erosion resistant crops can improve the productive soil.
 CROPPING SYSTEM Avoiding of monocropping and practicing mixed
cropping helps to increase the soil health. Cultivation of cereals and
legumes modifies soil quality and increases the nutrient availability of
soil.
 DIVERSITY IN FARMING SYSTEM IFS helps to improve the soil quality
by interconnected one enterprise to another enterprise. This also helps
to increase the farm income.

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CLASSIFICATION OF MANURE
 Farm Yard Manure (FYM):
Incorporation of FYM resulted in build-up in Soil Organic Carbon.)A buildup of
organic carbon in the soil due to continuous application of manure and crop residues has
also been reported by several scientists. Application of FYM alone or with fertilisers has
improved physical, chemical and biological properties of soil. Application of FYM has
improved soil physical conditions viz., stable soil aggregates, density, soil moisture holding
capacity and soil air movement. FYM application also has a positive influence on the
nutrient availability. Available nitrogen content has a direct relationship with organic
carbon content of the soil.it also increase in available nitrogen with application of FYM,
and also observed improved nitrogen use efficiency. They also observed buildup of
available P2O5 in plots applied with FYM. The decomposition of FYM releases certain
compounds which help in enhanced dissolution of native P compounds. The build-up of
available P2O5 is attributed to this process. FYM application also has a positive influence
on available potassium. FYM is not only a direct and ready source but helps in minimizing
the leaching loss of K by retaining K ions on exchange sites.
Availability of major secondary and micro nutrients such as Calcium, Magnesium,
Sulphur, Zinc, Copper, Manganese and Iron increased in fields applied with FYM. In
Manure
Bulky OM
FYM
Compost
Green Manuring Vermicompost
Concentrated
OM
Plant Origin
Neem Cake
Mahua Cake
Mustard cake
Karanj Cake
Animal Origin
Bone Meal
Blood Meal
Meat Meal
Fish Meal
Guano

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addition to all these, the beneficial microbial population and enzyme activities were
enhanced significantly on application of FYM.
 Compost
Composting is a advocated for recycling of different types of bio degradable organic
matter by converting them valuable manure.It is done by different aerobic & anaerobic
microorganism and have a optimum C:N ratio.
 Green Leaf Manure (GLM)
Improvement in soil porosity and maximum water holding capacity (MWHC) was
recorded with Green Manure application in vertisols. Reduction in bulk density and
improvement in aggregate stability, extractable carbon, sugar and microbial biomass was
recorded (Prabhakar et al. 2002). With green manuring population of N2 fixers and
phosphate solubilizes increased considerably. Another study recorded a significant increase
in the bacterial population and microbial biomass of N in the soil amended with green
manures .Growing of legume as green manure helped to save 60 kg nitrogen for the
succeeding paddy crop.
BASED ON
SUBSTRATE USED
Rural
compost
Urban
compost
BASED ON
OXYGEN USED
Aerobic
Anaerobic
BASED ON
TEMPERATURE
Mesophylic
Thermophilic
BASED ON
TECHNOLOGY
Open
Composting
Mechanical
Composting
Classification Of Composting

8. 7
 Vermicompopsting – Vermicomposting is a composting aided by
earthworm.As they consume 2-5 times of their body weight and a excret mucus coated
undigested matter known as vermicast. One tonnes of moist organic matter can converted
300kg of vermicompost.The main sps. of earthworm Eisenia foetida, Pheretima elongate
,eudrillus eugeniae etc. the vermicompost is very rich in different nutrients which helps the
soil health very much.And the earthworms are also known as the friend of farmers as well
as their presence in field indicates the very good physical, chemical, and biological status
of soil.
 Liquid manures
Use of traditional knowledge based liquid manures viz., Panchagavya, Jeevamrutha,
Beejamrutha Amritpaani and biofertilisers in paddy with and without compost indicated
that, paddy yield obtained under organic farming was equal to research station yield.
Application of Panchagavya and Jeevamrutha to paddy at monthly interval has resulted in
lush green colour of the crop and the crop was fairly free from pest and diseases. Further,
the microbial population viz., N fixers, P solublisers and actinomycets were very high
compared to control plots.Cowdung is rich in agriculturally beneficial microorganisms.
Organic farmers in India widely prepare and use a traditional knowledge product Amrit
Paani (1kg dung, 1l urine, 50g jaggery made to 10l with water, stirred every day 4-5 times,
ready for use as soil applicant on day 4) and was found having high population (more
than 0.1 million per ml) of these bacteria.
Their population was at par or more than some of the inoculants manufactured by
bioproducts industry and sold in the market
Image: Panchagavya is prepared mainly using the five products of the cow - milk, curd,
ghee, urine and dung.

9. 8
Effects of Organic manures on Soil health-
Soil is a living, dynamic ecosystem and healthy soil is the foundation of the food
system. It produces healthy crops that in turn nourish people. Maintaining a healthy soil
demands care and effort from farmers because farming is not benign. Plants obtain
nutrients from two natural sources: organic matter and minerals. Soil organic matter (SOM)
and specifically soil organic carbon (SOC) are known to play vital role in the maintenance
as well as improvement of soil environment. Soil organic matter is a critical component of
the soil resource base, which affects the biological, chemical, and physical processes of the
soil and, through the effect on these processes, fulfils a very wide range of functions.
A. Effects on soil physical environment-
1. Soil structure and aggregate stability: Soil structural stability refers to the
resistance of soil to structural rearrangement of pores and particles when exposed to
different stresses. Soil structure is stabilized by a variety of different binding agents. Soil
organic matter is a primary factor in the development and modification of soil structure.
While binding forces may be of organic or inorganic origins, the organic forces are more
significant for building large, stable aggregates in most soils. Examples of organic binding
agents include plant and microbially derived polysaccharides, fungal hyphae, and plant
roots. Both the stable and the active fraction of SOM contribute to and maintain soil
structure and resist compaction.
2. Soil water regimes: It has been observed that soils with higher SOM are “fluffier”
or have better “tilth” than soils with less SOM. This is because SOM is less dense than the
mineral soil particles per unit of volume, and therefore provides greater pore space for
water and air to be held. The result of increasing SOM is greater soil pore space, which
provides an area for water to be stored during times of drought. A unique characteristic of
the pore space in SOM is that the pores are found in many different sizes. The large pores
do not hold water as tightly, and thus will drain more readily. The medium and small-
sized pores will hold water more tightly and for a longer period of time, so that during a
dry period the soil retains moisture and a percentage of that water is made available over
time for plant uptake. The benefit of leaving residue on the soil surface and increasing soil
organic matter is that water infiltration is increased, soil crusting is decreased, and the soil

10. 9
can hold more of the water that infiltrates and will eventually make it available for plant
use.
3. Soil Temperature: SOM imparts dark brown or black soil colour which is
important for ensuring good thermal properties, which in turn contribute to soil warming
and promote biological processes. Only about 10% of the solar energy reaching the earth’s
surface is actually absorbed by the soil, which can be in turn used to warm the soil.
Naturally, dark coloured soils absorb more energy than light colored ones. However, this
does not imply that dark coloured soils are always warmer, since dark coloured soils usually
have a higher amount of organic matter, which holds comparatively larger amounts of
water; a greater amount of energy is required to warm darker soils than lighter coloured
ones. Thus, the thermal property of soil is to a large degree influenced by water content,
Db, soil texture (fine versus coarse) and soil colour. In addition, the surface cover of soil
affects the heat transfer in and out of a soil. As bare soils warm up and cool off more
quickly than those with a vegetation or mulch cover. Thus presence OM acts as a insulator,
retarding heat movement between the soil and atmosphere.
4 Soil Air- It helps to increase the macro pores in soil which is the main source of the
plant root respiration.
5. Bulk Density- With increase in organic content in soil the bulk density decreases
which helps in ploughing. In surface soil there is more organic matter present, so bulk
density is less than sub soil. It reduces soil compaction.
B. Effects on soil chemical environment
1. CEC: The density of cation exchange capacity (CEC) of organic matter is greater than
it is for
clay minerals (Table 1). It has thirty times more cation absorption capacity than that of
mineral
colloids. The different functional groups viz. carboxylic acids (54%), phenolic and hydroxil

11. 10
groups (36%) and amide groups (10%) of SOM are believed to be one of the main
contributors to
CEC as they provide negatively charged sites.
Table 1:
Cation exchange capacity of different soil particles
Soil particle CEC (cmol/kg)
Humus 100-300
Smectites (black swelling clays) 60-150
Kaolinite (white potter’s clay) 2-15
Iron and aluminium oxides (from ferrosols) <1
The organic matter increase the nutrient holding capacity, which helps to maintain the
nutrient status of the soil.
2. Soil PH- It is the –ve log of active H+ ion in the soil solution. By intensive use of
fertilizers and as well as high rainfall the soil ph hampers very much. But the organic matter
has the buffering capacity to soil ph. Generally in alkaline soil the application of organic
manures helps the ph to become normal.
Organic Carbon- organic matters helps to enrich the soil with carbon which is a main food
for the microorganism. Organic carbon helps to maintain the ratio of C:N in soil which
helps to decompose the organic matter. 58% organic carbon present in organic matter.
3. Buffering capacity of soil: The availability of different functional groups (e .g.
carboxy lic, phenolic, acidic alcoholic, amine, amide and others) allows SOM to act as a
buffer over a wide range of soil pH values. Due to this, likelihood of damage to plant roots
from acids and salts, whether naturally present or added through fertilizers reduces.
4. Nutrients availability: OM accelerates decomposition of soil minerals over time,
making the nutrients in the minerals available for plant uptake. OM can be considered as
the store house of different nutrients; essential to plant growth. OM is the source of 90-95
per cent of the nitrogen in unfertilized soils. In addition, OM supplies available
phosphorus, sulphur and some other micronutrients like Fe, Mn, Cu and Zn ets to the soil
and thereby increases the nutrient regime as well as improves the soil health. The ratio of
carbon:nitrogen:sulphur:phosphorus in organic matter is roughly 100:10:1.5:1.5. A soil
which weighs 1,000,000 kg, with a carbon content of 1% would contain 1,000 kg of
organic nitrogen, and 150 kg each of organic phosphorus and sulphur per hectare. Not all

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of this is mineralized each year, but there is considerable potential for nutrients in organic
matter to contribute to plant requirements.
C. Effects on soil Biological Environment
Healthy soil is teeming with microscopic and larger organisms that perform many vital
functions including converting dead and decaying matter as well as minerals to plant
nutrients. Different soil organisms feed on different organic substrates. Their biological
activity depends on the organic matter supply. Soil organic matter is the driving force for
providing food for the living organisms in the soil, which enhances soil microbial
biodiversity and activity. Microorganisms only make up a small portion of the SOM (less
than 5%) they are imperative to the formation, transformation, and functioning of the
soil. In the soil, they conduct indispensable processes such as decomposition, nutrient
cycling, and degradation of toxic materials, N fixation, symbiotic plant relationships, and
pathogen control.
PHYSICAL FUNCTIONS
•Influence soil
temperature
• Bind soil particles
together in stable
aggregates
•Influence water
holding and
aeration
CHEMICAL FUNCTIONS
• Source of pH
buffering
• Major source of
cation exchange
capacity
• Binding site for
heavy metals and
pesticides
BIOLOGICAL
FUNCTIONS
•Major reservoir of
plant nutrien
•Food source for
microbes and small
animals

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CONCLUSION:
There are several benefits of organic manure in improving soil quality and soil health and
the quality soil is the most important and primary input of crop production.
By intensive agriculture the organic matter status of soil declined day by day. So, to
improve the fertility status of soil, use of organic manure instead of inorganic chemical
fertilizer is a common practice and this concept originated along with the crop production.
Until mid of nineteenth century the organic manures were the only source of nutrient
required by the crop plants. Even today its application is supposed to be of prime
importance despite of tremendous advances made in the field of agriculture. Organic
manure improve soil quality by modifying soil physical property, increase biological
activity i.e, micro-organism activity, helps in decomposition of organic matter etc. Organic
manure helps plants to quick uptake of nutrients from soil, increase nutrient availability in
soil, reduces soil pollution, minimize soil erosion and degradation, improve nutritional
security and reduce many problems related to crop production. Lastly, we can say that
application of organic manure and practice of organic farming has a desirable effect on
sustainable food production.