What Are the Different Types of Compost and Which Should I Use in My Garden?
Composts are natural fertilisers and source of nutrients for plants. They are bulky sources of organic matter which supply nutrients in small quantities but organic matter in large quantities. They are prepared by the decomposition of animal excreta and plant waste.
Types of Compost
- farmyard manure,
- green manures,
- and vermicompost.
Long lasting in the soil, nutrient rich
Storage problem, can acidify the soil
Adds organic matter to the soil, improves soil texture, leguminous crops add nitrogen
Not nutrient specific
Rice, maize, sugarcane, cotton, wheat
Economic and environment friendly waste management, low cost
Waste segregation is required
Fruits and vegetables
Improves water retention capacity of soil, enhances germination, plant growth and crop yield
Proper environmental conditions have to be maintained for earthworms to thrive
Farmyard Manure (FYM)
Farmyard manure (FYM) is the decomposed mixture of cattle excreta and urine along with litter and leftover organic matter such as roughage or fodder. These waste materials are collected daily from the cattle shed and stored in a pit for decomposition by the microorganisms. It contains nitrogen, phosphorus, and potassium.
Advantages of Manures
- They enrich the soil with nutrients. They replenish the general deficiency of nutrients in the soil.
- The manures add organic matter called humus to the soil which restores the soil texture for better retention of water and for aeration of the soil. For example, organic matter present in the manures increases the water holding capacity of the sandy soil and drainage in clayey soil. They also avoid water logging in clay soils.
- The organic matter of the manures provides food for the soil organisms which help in making nutrients available to plants.
Thus, organic manures help to improve the physical properties of soil, reduce soil erosion, increase the moisture holding capacity of soil and above all these advantages, they are low-cost nutrient carriers. Using biological waste is a way of recycling the farm waste. Manures also protect our environment from the harmful effects of synthetic chemicals or fertilisers.
Disadvantages of Manures
- Manures are bulky with low nutrient content. The nutrients of manures are released slowly, not keeping pace with the high and rapid demand of nutrients by improved high-yielding hybrid varieties of crops.
- Being bulky and voluminous, they are inconvenient to handle, store, and transport.
- Moreover, a manure is not nutrient specific and hence, it is not much useful when a particular nutrient is required in the soil for a particular crop.
Compost is prepared from farm and town scraps such as vegetable and animal refuse and waste, weeds, crop stubble, clippings, rice hulls, forest litter, etc. Composting is a biological process in which both aerobic and anaerobic microorganisms decompose the organic matter. It takes about 3 to 6 months for decomposition of organic refuse.
How to prepare a compost:
- A hole of suitable size (4 to 5 m long, 1.5 to 1.8 m broad and 1.0 to 1.8 m deep) is dug.
- A layer of well-mixed refuse of about 30cm thickness is spread in the hole.
- This layer is well moistened by the slurry of cattle dung or soil and water.
- The second layer of mixed refuse is spread in the hole until the heap rises to a height of 45 to 60 cm above ground level.
- The top of this heap is then covered with a thin layer of moist earth.
- After 3 months, the partially decomposed biomass is taken out and collected in a conical heap.
- This heap is moistened if necessary and covered with earth. After another one or two months, the compost is ready for use in the field.
The practice of green manuring includes growing, mulching by ploughing, and mixing of green crops with soil to improve physical structure and soil fertility. Green manures may include both leguminous and non-leguminous plants such as Egyptian clover, cluster beans, etc. Such plants are used to add nitrogen, phosphorus, and other organic matter to the soil to improve crop yield.
Green manure crops are grown in the field for about 6 to 8 months and turned into the field at flowering stage. These crops remain buried for about one to two months. Plants should be completely decomposed before sowing the next crop. Generally, the crops which require high nutrient input are raised in the green manured field, such crops are rice, maize, sugarcane, cotton, and wheat.
The degradation of organic waste by earthworms is called vermicomposting. An earthworm is physically an aerator, crusher, and mixer. Chemically it is a degrader and biologically a stimulator of decomposition. This is an appropriate technique for efficient recycling of animal wastes, crop residues, and agro-industrial wastes.
Vermicompost can be prepared from all sorts of organic wastes, agricultural residues, animal manures, dairy and poultry wastes, food industry wastes, municipal solid wastes, and biogas sludge.
Though manures lack in plant nutrients, they are rich in organic matter and cheap. They are environment-friendly and do not cause any type of pollution either to the soil or to water. They enrich the soil with humus and improves the overall quality of the soil like soil texture, soil aeration, and water holding capacity.