The E-mail Conference on 'On-farm Composting' organized by the Land and Plant Nutrition Management Service deserves much appreciation. I believe that the Conference is timely, for of the following reasons: Marginal and small farmers are moving out of their farms, due to uneconomic returns and declining fertility and productivity.
Deforestation and intensive cropping have led to poor availability of green leaf and green manures required for the farm.
More and more farm mechanization is reducing the livestock population, resulting in inadequate generation of organic manures, the addition of which is critical for protecting soil health.
Reduced availability of manpower for farm jobs and taking up of other avocations by land owners for additional income have resulted in neglecting the collection of farm refuse and its composting.
It is common knowledge today that the spectacular yields obtained during the Green Revolution period, in countries like the Philippines and India, are no longer possible, in spite of heavy application of chemical fertilizers. This is because of declining soil health, owing to the neglect of organic manure addition.

Viewed in this context, this E-mail Conference assumes great significance. I would like to share with you the information on one of the popular composting methods developed in India:

This composting method was developed at the Agricultural College and Research Institute, Coimbatore, India, involving a decade of systematic work. It was developed bearing in mind the general availability and nature of farm wastes and its applicability to tropical conditions. The method is described below and is called the "Indian-Coimbatore Method":

Indian-Coimbatore Method

In this method, the mode of decomposition is semi-aerobic. A pit of 360 cm (l) x 180 cm (b) x 90 cm (d) is dug in a shady area (length can be varied depending on the volume of waste materials available). Farm wastes like straw, vegetable refuse, weeds, leaves, etc. are spread to a thickness of 15 to 20 cm. Over this layer, wet animal dung is spread to a thickness of 5 cm. Water is sprinkled to make the material moist (50-60% of mass), if necessary.

This procedure is repeated until the whole mass rises to a height of 60 cm above ground. Then it is plastered with mud and anaerobic decomposition sets in. In four weeks, the mass becomes reduced and the heap flattens. The mud plaster is removed and turning is given to the entire mass. Aerobic decomposition sets in at this stage. Water is sprinkled to keep the material moist. The compost is ready for use in four months (Manickam, 1967). This method is simple in construction and easy to adopt. However, the following modifications to this basic method further improve the quality of compost and reduce the maturity period. These techniques can be adopted wherever the required materials are available.

1. Addition of P
Farm compost is poor in P content (0.4-0.8%). Addition of P makes the compost not only more balanced, but also supplies nutrient to micro-organisms for their multiplication and faster decomposition. Loss of N also is reduced by the addition of P.

1.1 Application of Super Phosphate or bonemeal or Rock Phosphate: one kilogram of Super Phosphate or bonemeal is applied over each layer of animal dung. Low grade Rock Phosphate can also be made use of for the purpose.

1.2 In villages, like in Africa, animal bones are easily available. These can be broken into small pieces, boiled with wood ash leachate or lime water and drained, and the residue applied to the pits in lieu of above P source. This procedure of boiling bones helps in easy disintegration of bones (Ramasami, 1975). Even the addition of raw bones, broken into small pieces and added to the pit, improves the nutrient value of compost significantly. Wood ash waste, if available, can also be added with P source for increasing the K content of compost.

2. Using Microbial Cultures

2.1 Addition of cellulolytic (cellulose decomposing) cultures: research has shown that the inoculation of compost pits with cellulolytic cultures helps to speed up decomposition, i.e. reducing the wide C/N ratio of 50-60:1 to around 20:1 (Subba Rao, 1988). The organisms found useful for the purpose are Chaetomium abuanse, Trichoderma viride (fungi); Cellulomonas sp., Aspergillus niger, A.terreus, etc. (the Microbiology Division of Mahatma Phule Agricultural College, Pune, India has developed an excellent method of multiplying and maintaining these organisms using sorghum grains as substrate).

2.2 Application method: water suspension of these cultures is sprinkled on every layer of farm waste. Using these cultures will make the compost ready in two months' time (IARI Bulletin, 1989).

3. Addition of N-fixing and P-solubilizing cultures

The quality of compost can be further improved by the secondary inoculation of Azotobacter, Azospirillum lipoferum, Azospirillum brasilence (N fixers) and Bacillus megaterium or Pseudomonas sp (P solubilizers). These organisms, in the form of culture broth or water suspension of Biofertilizer products, can be sprinkled when the decomposing material is turned after one month. By this time, the temperature of the compost also gets stabilized at around 35oC. As a result of this inoculation, the nitrogen content of even straw compost can be increased up to 2%. These additions, besides improving N content and the availability of other plant nutrients, also help in reducing the composting time considerably.

References:
I A R I Bulletin, 1989. `Biofertilizers', Division of Microbiology, Indian Agricultural Research Institute, New Delhi.

Manickam T.S., 1967. Chemistry of Fertilizers and Manures, Division of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, Coimbatore, India.

Ramasami S., 1975. Processing of Bones into Bonemeal and its effect on Plant Growth, Ph.D. Thesis, Indian Agricultural Research Institute, New Delhi.

Subba Rao N.S., 1988. Biofertilizers in Agriculture, Oxford & IBH Publishing Co Pvt Ltd, New Delhi.

From: S Ramasami, Madras Fertilizers Ltd
Chennai, India
e-mail: dama@md3.vsnl.net.in