Microbial Degradation Process that Converts Organic
Matter to a Stable Humus like Product under Controlled
Compost Compost is a microbiologically well decomposed
black to brown amorphous organo-mineral
More about food for your decomposers
Your compost workers will thrive if you give them a
• Composting will be most rapid if the decomposers are
fed a mix of carbon rich and nitrogen rich materials.
• Carbon rich organic wastes are known as “browns”
Leaves (30-80:1) ;Straw (40-100:1) ; Paper (150-200:1); Sawdust
(100-500:1); Animal bedding mixed with manure (30-80:1)
• Nitrogen rich organic wastes are known as “greens”
Vegetable scraps (12-20:1); Coffee grounds (20:1);
Grass clippings (12-25:1); Manure- Cow (20:1); Horse (25:1);
Poultry (10:1), with litter (13-18:1)
The word compost is derived from the Latin word “COMPONERE” to
mean put together
Basic principles underlying Composting
Waksman et al.1949
Composition of plant materials
Mechanism of decomposition process which are
brought about by microbes.
Aerobic vs anaerobic
A knowledge of Metabolism of these micro organisms.
Types of composting
Composting may be divided into two categories by the nature of the decomposition
process. In anaerobic composting, decomposition occurs where oxygen (O) is absent
or in limited supply. Under this method, anaerobic micro-organisms dominate and
develop intermediate compounds including methane, organic acids, hydrogen
sulphide and other substances. In the absence of O, these compounds accumulate
and are not metabolized further. Many of these compounds have strong odours and
some present phytotoxicity. As anaerobic composting is a low-temperature process,
it leaves weed seeds and pathogens intact. Moreover, the process usually takes
longer than aerobic composting. These drawbacks often offset the merits of this
process, viz. little work involved and fewer nutrients lost during the process.
Aerobic composting takes place in the presence of ample O. In this process, aerobic
microorganisms break down organic matter and produce carbon dioxide (CO2),
ammonia, water, heat and humus, the relatively stable organic end product.
Although aerobic composting may produce intermediate compounds such as organic
acids, aerobic micro-organisms decompose them further. The resultant compost, with
its relatively unstable form of organic matter, has little risk of phytotoxicity. The heat
generated accelerates the breakdown of proteins, fats and complex
carbohydrates such as cellulose and hemi-cellulose. Hence, the processing time
is shorter. Moreover, this process destroys many micro-organisms that are human
or plant pathogens, as well as weed seeds, provided it undergoes sufficiently high
temperature. Although more nutrients are lost from the materials by aerobic
composting, it is considered more efficient and useful than anaerobic composting
Essential requirements for composting :Massive organic Refuge
CEREAL STRWS, CROP STUBBLES, COTTON STALKS, GN HUSKS,
SUGARCANE TRASH, FARM WEEDS AND GRASSES, HOUSE
REFUSE, WOOD ASH, LIITER, URINE SOAKED EARTH FROM
A suitable starter
URINE, DUNG, SEWAGE, SLUDGE, A/S, NaNO3, CaCN2
Addition of water
50-60% WATER for satisfactory decomposition
Presence of Air :
Oxidation process, requires O2, air to be introduced
to the compost heap after 10-15 days
Points likely to remember for successful preparation of quality compost:
• Selection of suitable composting substrates- on the basis of C/N ratio
and the content of recalcitrant material, alkaloids, phytotoxic materials,
obnoxious substances, heavy metal and pesticides.
• Recipe of composting substrates- To have quality compost there should
have definite blending ratio between the base raw materials and among
other supportive substrates. Waste: raw cowdung:live soil :FYM,
8:1:0.5:0.5 is the right blending mixture(on dry weight basis) for quality
• Methodology of composting- Composting methods like Heap, pit, windrow
etc are used. But composting in heap produces good quality of compost
and cost involvement is less.
• Use of compost culture- Carrier based composting culture (@0.05%) for
expedite the rate of decomposition will help for quality compost
• Enrichment of composting- Compost is inheritantly low in plant nutrients.
Fortification with biotic e.g. N-fixing and P-solubilizing organisms and
organic farming acceptable naturally occurring low grade abiotic inputs like
rockphosphate, pyrite etc can improve the nutrient status of the product.
20% rockphosphate, 5% pyrite and 0.05% each of nitrogen fixing bacteria
and phosphate solubilizing m.o can improve the quality of compost wrt N and P.
Criteria for Composting
C : N ratio - 25-35 : 1
Particle size - 50 mm
Moisture content - 50-60%
Air flow - 0.6-1.8 m3/day/kg
Temperature - 550C - 600C
for 1st 3 days
Agitation - Periodic turning
at 15 days interval
Heap size - Any length,
1.5 m high, 2.5m wide
Activators - Microbial inoculants
Hutchinson and Richards(1921) at
Rothamsted Experimental Station , England
ADCO powder as a starter material
Muriate of potash
Ground lime stone
@ 7.0 kg/ 100 kg dry waste
: 60 lbs
: 30 lbs
: 25 lbs
: 50 lbs
The basic raw material straw is
spread in layers and sprinkled over with
a solution of ammonium sulphate. Then
powdered lime stone is applied as
broadcast. Then another straw layer is
put on. The piling of the layer is
continued till a decent heap of
convenient height is built up. After about
3 months of fermentation the resulting
material is similar to FYM and hence
called “synthetic FYM”
1 ton dry Compost
Howard and Wad,(1931)
Indian Institute of Plant Industry, Indore
Cowdung as starter
Prepare a trench having dimension; 30′x 14′ x 3′(Trench)
Stalks of cotton, maize, millet and the pulses. (Ideally they should be chopped
to a particle size below 2 inches).
Start building the heaps by laying a lattice of old branches at the bottom. Divide
the base area of the heap into a 6 (roughly equal) transverse sections, five of
which are filled and one left vacant.
Make each section of 7 layers (figure 1) of 9″ thickness. In a
9″ layer, have 4″ of dry waste, 3″ of green weeds and
leaves, 2″ of FYM and a sprinkling of urine-earth-wood ash.
(The layering process is illustrated in figure-2).
Make 3 ventilation holes or vent of 4″ diameter.
The first pole should be in the middle at a distance of not more than 7′ feet from the
heap, the rest two vent will be in two corners with a maximum distance of 3½ft from
Continue building of the section up to a height of 5′, after establishing the air vents.
Build five sections in the similar manner, leaving the sixth one vacant (The sixth
one is utilized while turning the heap).
Water the heap, lightly, just after completion and again in the next morning.
Turning also facilitates thorough mixing of the ingredients and their aeration.
Carry out 1st turnings after 2 weeks,followed by 2nd turning after 5 weeks. A third
turning is realized only if the original materials are recognizable, after 9 weeks. It takes
around 12 weeks for final composting, though a little longer during monsoons.
The final product has a pliable texture, an earthy smell and is dark brown or grey
in colour. This matured compost is half of its original volume as it simply shrinks due
to the cooling process.
process [ Aerobic and anaerobic process] :
This process of composting was developed byDr.C.N.Acharya in the year 1949
1. Basic raw material used: Any organic material
2. Starters or inoculants[Undecomposed: FYM or mixture of dung and urine or
3. Additives:Bone meal or oil cakes , wood ash
NADEP METHOD OF COMPOSTING
Narayan Deotao Pandharipande of Maharastra (Pusad).
This method of making compost involves
the construction of a simple, rectangular
brick tank with enough spaces maintained
between the bricks for necessary aeration.
The recommended size of the tank is 10’
(length) x 5’ (breadth) x 3’ (height). All
the four walls of NADEP tank are provided
with 6// vents by removing every alternate
brick after the height of 1ft. from bottom
for aeration. Tank can be constructed in
mud mortar or cement mortar.
Raw materials required for filling NADEP tank:
Agricultural waste (Dry & green)
: 1350-1400 kg.
Cattledung or biogas slurry : 98 –100 kg.
fine sieved soil – 1675 kg.
Water – 1350-1400 litre.
The important technique: the entire tank should be filled in one go, within 24 hours
and should not go beyond 48 hours, as this would affect the quality of the compost.
Before filling, the tank is plastered by dilute cattle
dung slurry to facilitate bacterial activity from
all four sides. It is also filled in definite layers
each layer consisting of the following sub layers.
4 to 6// thick layer of fine sticks, stems, (To
facilitate aeration) followed by 4 to 6// layer of
dry and green biomass.
4 kg Cow dung is mixed with 100 litre of
water and sprinkled thoroughly on the
agricultural waste to facilitate microbial activity.
60 kg of fine dry soil is spread uniformly
over the soaked biomass for moisture retention
and acts as a buffer during biodegradation
Thus the proportion of organic materials for
each layer is 100 kg organic biomass: 4kg
cowdung + 100 litre water+60 kg soil. In this
way, approximately 10 -12 layers are filled in
each tank. After filling the tank, biomass is
covered with 3// thick layer of soil and sealed
with cow dung + mud plaster
**** EM-based quick composting
Effective micro-organisms (EM) consist of common and food-grade aerobic and
anaerobic micro-organisms: photosynthetic bacteria, lactobacillus,
streptomyces, actinomycetes, yeast, etc.
A unit consists of 9 pits measuring about 180 cm (length) × 120 cm (width) ×
90 cm (depth), enclosed by low walls and covered with a roof
Raw materials for compost
Preparation of EM solution (accelerator)
EM-based quick composting in Myanmar
One litre of 'instant solution' is made by
Mixing 10 ml of EM, 40 ml of molasses and
950 ml of water and leaving it for 5 to 7 days, depending on temperature. The solution
is then added to 1 litre of molasses and 98 litres of water to obtain 100 litres of
ready-to-use EM solution. This amount is enough for 3 pits. The EM solution functioning
as accelerator reduces the composting period from 3 months to 1 month.
***Composting organic materials with high lignin content coir pith
Coir pith is a waste from the coir industry (TNAU, 1999). During the process
of separating fibre from the coconut husk, a large volume of pith is
collected. The pith, containing about 30% lignin and 26% cellulose, does
not degrade rapidly, posing a major disposal problem.
However, it can be composted by using the fungus Pleurotus sp. and urea.
To compost 1 tonne of coir pith, the materials required are:
5 spawn bottles (250 g) of Pleurotus sp. and 5 kg of urea
The first step in the compost preparation is to select an elevated shaded
place, or to erect a thatched shed. The surface is then levelled and an area
500 cm × 300 cm is marked out. To start with, about 100 kg of coir pith is
spread. About 50 g of Pleurotus spawn is spread over this layer. About
100 kg of coir pith is spread on that. On this layer, 1 kg of urea is spread
uniformly. The process is repeated until all the pith (1 tonne) is utilized.
Water is sprinkled repeatedly so as to maintain the moisture optimum of 50
%. Well-decomposed black compost is ready in about a month. The C:N
ratio falls to about 24:1 and the N content rises from 0.26 to 1.06 percent.
This method has been developed for composting weeds such as
parthenium, water hyacinth (Eichornia crassipes), cyperus (Cyperus
rotundus) and cynodon (Cynodon dactylon).
The materials required are:
250 g of Trichoderma viride , Pleurotus sajor-caju consortia, and 5 kg
An elevated shaded place is selected, or a thatched shed is erected.
An area of 5 m × 1.5 m is marked out.
The material to be composted is cut to 10-15 cm in size.
About 100 kg of cut material is spread over the marked area.
About 50 g of microbial consortia is sprinkled over this layer.
About 100 kg of weeds are spread on this layer.
1kg of urea is sprinkled uniformly over the layer.
This process is repeated until the level rises to 1 m.
Water is sprinkled as necessary to maintain a moisture level of 50-60% .
Thereafter, the surface of the heap is covered with a thin layer of soil.
The pile requires a thorough turning on the twenty-first day.
The compost is ready in about 40 days.
When is compost finished?
Compost is mature when
• The color is dark brown
• It is crumbly, loose,
• It has an earthy smell
• It contains no readily
• The pile has shrunk to
about 1/3 of its original
Size Reduction of Heap
Colour of Product
Smell of Product
Presence of Weed Seed
Seed Germination Test
Presence of Pathogens
Method of preparation of liquid manure
1.5 kg fresh cow dung and 1.5 kg fresh green leaves of Subalul and
Babla are to be taken in a closed mouth cotton bag.
The bag is then placed inside 40 litres water taken in a drum.
The drum is to be kept in a open place with covering the mouth for
about 20 days.
The water is to be stirred every morning with a stick by removing the
cover over the drum and the whole task is to completed as quickly
After the required time period (there would be no bad odour and
the colour of the liquid will change to light tea liquor) the
concentrated liquid is then diluted with water 5 times (that means
total volume of the liquid then come to 200 litres).
The diluted liquid is then applied either on soil surface or on the
Preparation of liquid manure
1.5 kg fresh cow dung + 1.5 kg fresh green leaves
40 litre of water
(after around 20 days)
Diluted and the final
volume is 200 litre
The average nutrient content of the
N – 1%, P2O5 – 2% , K2O – 2%.
Upon this handful of soil
Our Survival depends
Husband it & it will grow
Our food, fiber & fuel
& surround us with beauty,
Abuse it, the soil will degrade
& collaspe taking mankind
Composting organic materials with high lignin content - lime
By adding organic wastes such as sawdust, wood shavings, coir pith, pine
needles, and dry fallen leaves, while preparing organic waste mixtures for
composting, one can ensure that the compost produced contains sufficient
and long-lasting humus. However, gardeners often find that where they use
lignin-rich plant materials, the compost does not ripen rapidly.
A technique for making good compost from hard plant materials
involves mixing lime in a ratio of 5 kg per 1 000 kg of waste material. Lime
can be applied as dry powder or after mixing with a sufficient quantity of
water. Treatment with lime enhances the process of decomposition of hard
materials. Liming can enhance the humification process in plant residues by
enhancing microbial population and activity and by weakening lignin structure.
It also improves the humus quality by changing the ratio of humic to fulvic
acids and decreases the amount of bitumen, which interferes with the
decomposition process. Instead of lime, powdered phosphate rock can be
used in a ratio of 20 kg per 1 000 kg of organic waste. Phosphate rock
contains a lot of lime. The phosphates and micronutrients contained in
phosphate rock make composts rich in plant nutrients
A unit pile is about 5(l) ×1(w) ×1(h)
m3 in size.
1. Compost pile in preparation
2. The pile is covered with a plastic
sheet after attaining the desired height
Straw is stacked in layers of 20
cm height, 1 m width, and 5 m
length to form a pile.
The pile is sprinkled with water
(Plate 1) for adequate moisture
followed by addition of a FYM
layer 5 cm high,
and the sprinkling of a few
handfuls of urea (100-200 g).
EM solution is sprinkled to
accelerate aerobic decomposition.
This procedure is repeated until
the pile is about 1 m high and
then it is covered with a plastic
sheet (Plate 2).
3.The pile is being turned
The pile is turned after two weeks (Plate 3) and then again
after another week. Normally, the compost is ready two
weeks later when the heap has cooled down and the height
of the pile has fallen to about 70 cm.
Using the natural process of decay to change
organic wastes into a valuable humus-like
material called compost
Materials to avoid during composting
Avoid organic materials that could cause problems during or
• Oil, fat, grease, meat, fish or dairy products, unwashed egg
shells (tend to attract pests, vermin)
• Hard to kill weeds (bindweed, quackgrass) and weeds that
have gone to seed (could infest garden area when
compost is used).
Cat or dog waste attracts pests,
could spread disease)
Diseased or insect ridden plants
(could infect or attack garden plants when
compost is used)
Assume that a representative cultivated soil in a condition favouring
vigorous nitrification is examined. Nitrates are present in relatively large amounts and
the C:N ratio is narrow . The general purpose decay organisms are at a low level
of activity, as evidenced by low carbon-di-oxide production.
Now, suppose that the large quantities of organic residues with a wide C:N
ratio (50:1) are incorporated in the soil under conditions supporting vigorous
digestion. A change quickly occurs. The heterotrophic flora-bacteria, fungi, and
actinomyctes - become active and multiply rapidly, yielding CO2 in large quantities.
Under these conditions, nitrate nitrogen practically disappears from the soil
because of the insistent microbial demand for this element to build their tissues.
And for the time being, little or no N , is in a form available to higher plants. As decay
occurs, the C/N ratio of the plant material decreases since C is being lost and N
This condition persists until the activities of the decay organisms
gradually subside due to lack of easily oxidisable Carbon. Their number
dercrease, CO2 formation drops off, N ceases to be at a premium and
nitrification can proceed. Nitrates again appear in quantity and the original
conditions again prevail except that, for the time being, the soil is somewhat richer
both in nitrogen and humus.
This sequence of events, an important phase of the carbon cycle, is shown
in Fig. (previous slide).