Based on concentration of nutrient component, manures can be grouped into
bulky organic manures
concentrated organic manures
Bulky Organic Manures
Bulky organic manures contain small percentages of nutrients and are to be applied in large quantities.
Uses
Supply plant nutrients including micronutrients
Improve soil physical properties of soil like structure, water holding capacity etc.
Improves availability of nutrients
Plant parasitic nematodes and fungi are controlled to some extent by altering the balance of microorganisms in the soil.
The most important and widely used bulky organic manures are
Farmyard Manure: Farmyard Manure refers to the decomposed mixture of wastes of farm animals along with left over material from roughages or fodder fed to the cattle. Partially rotten farmyard manure has to be applied 3-4 weeks before sowing while well-rotten manure can be applied immediately before sowing. Vegetables crops like potato, tomato, sweet-potato, carrot, raddish, onion etc., respond well to the farmyard manure. The other responsive crops are sugarcane, rice, and orchard crops like oranges, banana, mango and plantation crop like coconut.
Compost: A mass of rotted organic matter made from waste is called compost. The compost made from waste like trash, paddy straw, weeds and other plants and waste is called farm compost. The compost made from town refuses like night soil, street sweepings and dustbin refuse is called town compost. Vegetables crops like brinjal, chilli, cabbage, cauliflower etc. and fruit crops like mango, papaya, litchi etc, response well to the compost.
Green Manure: Green undecomposed plant material is called green manure. The important plant species useful for green leaf manure are neem, mahua, wild indigo, glyricidia, subabul and other shrubs. Green manuring improves soil structure, increases water holding capacity and decreases soil loss by erosion. Green manure helps in reclamation of alkaline soils. The most important green manure crops are sunnhemp, dhaincha, clusterbeans and Sesbania rostrata.
Other Forms of Bulky Organic Manure
Vermicompost: Compost which is prepared with the help of earthworms is called vermicompost. The earthworms may be of local species or more vigorous exotic ones. Earthworms consume large quantities of organic matter and excrete soil as casts. Compost is ready within 2-3 months. The casts of the earthworm have several enzymes and are rich in plant nutrients, beneficial bacteria. Vermicompost is a rich mixture of major mixture of macro nutrients and micro nutrients which promotes plant growth. Presence of earthworms help in aerating the soil.
Sheep and Goat Manure: The droppings of sheep and goats contains higher nutrients than farmyard manure and compost.
Poultry Manure: In agriculture, poultry manure is a mixture of poultry excreta, spilled feed, feathers, and material used as bedding in poultry operations. Poultry manure contains higher nitrogen and phosphorus compared to other bulky organic manures.