Principles and Process of Compost Manufacture

After reading this article you will learn about the principles and process of compost manufacture.

Principles of Compose Manufacture:

Waste plant materials contain nutrients in the form in which plant roots cannot absorb them. Waste plant materials are decomposed by micro-organisms when complex organic form of nutrients like proteins are converted to their respective simple inorganic form in which plant roots can absorb them.

The plant waste materials are decomposed by microorganisms in the presence of sufficient available nitrogen, phosphorus, potassium and other essential elements which are used to synthesize cell protoplasm. If the waste plant material contains 1.2 per cent nitrogen on a dry weight basis, no extra soluble nitrogen is to be added to it.

Usually, however, plant waste materials contain about 0.5 per cent nitrogen, so about 0.7 parts of soluble nitrogen should be added to every 100 parts of the plant waste material, so that it is decomposed by micro­organisms to release the nutrients crops need for them growth.

Processes of Compost Manufacture:

(i) Indore Process:

The manure pit is provided with a roof to protect it from hot sun and heavy rain. It should be about one metre deep, two metres wide and five metres in length if the farmer possesses two pairs of animals. About 25 kg of dry waste plant material is spread under each pair of animals as bedding. The next morning, the mixture of cattle dung and urine soaked litter is taken to the manure pit and is spread uniformly at the bottom.

Slurry made of 4.5 kg cattle dung + 3.5 kg of urine earth + 4.5 kg of fungus inoculum + 0.5 kg of wood ash in 4 gallons of water, is uniformly applied over it. The fungal inoculum is the material taken from an old compost heap which contains the micro-organisms. Water is uniformly sprinkled over this material.

In this way, the compost pit is gradually filled up day-by-day when the layer of the mixture of cattle dung and urine soaked litter alternate with the layer or slurry and water till it raises about 30cms above the ground.

The composting material is dug out twice, 15 and 30 days after the manure pit has been filled up, water is sprinkled over it, it is thoroughly mixed and replaced in the pit. It is taken out of the pit after one month, water is sprinkled over the composting material which is thoroughly mixed, and a heap is made above the ground below a shed. It is ready in 3 to 4 months.

The main advantage is that well decomposed manure is obtained in a relatively shorter period. The disadvantage is the considerable labour cost due to turning and watering. Some organic matter and nitrogen are lost.

(ii) Bangalore Method:

A roof is provided over the manure pit whose dimensions are about the same as in the Indore method.

About 18 kg of waste plant material is spread as bedding under each pair of animals at the cattle shed for the night.

The next morning the mixture of cattle dung t urine soaked litter is taken to the manure pit, which is filled in sections of 60 to 120cms at a time.

A mobile wooden or bamboo partition is placed across the manure pit at a distance of 60 to 120cms from one end. The mixture of cattle dung and urine soaked litter is spread uniformly in this section. Water is uniformly applied to it.

Everyday a mixture of cattle dung and urine soaked litter is spread over the previous layer in the pit. When this section has been filled up, the temporary partition is removed and a similar section is made next to it. This second section is filled up in the same manner.

The manure trench is filled up section wise in this manner. Then it is thoroughly watered and plastered with mud. The manure is ready in about six months.

Advantage:

The cost of labour is saved because it is not stirred. The material slowly decomposes and therefore less organic matter and nitrogen is lost.

Disadvantage:

It takes longer time it is not well decomposed.

(iii) Coimbatore Method:

A roof is provided over the manure pit. It is three feet deep and four feet wide and its length depends upon the quantity of material available. Waste plant material is spread uniformly at the bottom of the pit. It is thoroughly moistened with a suspension of cow dung in water (@ 10 kg cow dung in 50 litres of water) and about half to one kilogram of powdered bone meal is sprinkled over it. Then it is thoroughly watered.

Again a layer of waste plant material is placed over the previous layer, it is moistened with the suspension of cow dung in water and powered bone meal is uniformly applied to it. In this way, the manure trench is filled up until the material in it raises about 60cms about the ground level.

The composting material is taken out of this manure pit after two months, water is applied to it. It is thoroughly mixed and a rectangular heap is made below a shed and left undisturbed. Occasionally, water is sprinkled over it. It is ready in about 6-7 months. Well prepared compost usually contains 0.8 to 1.0 per cent of nitrogen, has all the properties of farm yard manure and can be used the same way.