Apart from high yielding varieties of seeds, the use of chemical fertilizers was the hall mark of Green Revolution that led to production of bumper crops to meet the needs of teeming population. Though it was the need of the hour, but it also had its pitfalls. Given the harmful effects of synthetic chemicals, people across the globe became health conscious and concept of Organic Farming was popularised.
Organic Farming is an agricultural system that uses fertilisers of organic origin such as compost manure, green manure and bone meal and places emphasis on techniques such as crop rotation and companion planting. It is a production system that sustains the health of soils, ecosystems and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions rather than the use of inputs with adverse effects.
In Kashmir, though the fast food culture is nowadays common but some heath conscious people are keen to consume chemical free products, particularly fruits, vegetables, meat and milk. They tend to use cow dung manure for their crops instead of fertilisers. The demand for cow dung has risen so much that some farmers keep cows mainly for cow dung which is used as manure. Even the milk, poultry and vegetables that are produced organically fetch a far better price when given an Organic Tag!
Raw cow dung cannot be used as such on the plants because it contains higher quantities of salts and ammonia which as such can burn the roots of plants. The dung has to be converted into manure through a process of Composting and when composting is done with the help of earthworms, it is called vermicomposting. Earthworms simply accelerate the process.
Vermicompost: Production and Practices
Vermicomposting is a method of preparing enriched compost with the use of earthworms. It is one of the easiest methods to recycle agricultural wastes and to produce quality compost. Earthworms consume biomass and excrete it in digested form called worm casts. Worm casts are popularly called as Black Gold. The casts are rich in nutrients, growth promoting substances, beneficial soil micro flora and having properties of inhibiting pathogenic microbes. Vermicompost is stable, fine granular organic manure, which enriches soil quality by improving its physicochemical and biological properties. It is highly useful in raising seedlings and for crop production. Vermicompost is becoming popular as a major component of organic farming system.
Vermicomposting materials
Decomposable organic wastes such as animal excreta, kitchen waste, farm residues and forest litter are commonly used as composting materials. In general, animal dung mostly cow dung and dried chopped crop residues are the key raw materials. Mixture of leguminous and non-leguminous crop residues enriches the quality of vermicompost.
There are different species of earthworms viz. Eisenia foetida (Red earthworm), Eudrilus eugeniae (night crawler), Perionyx excavatus etc. Red earthworm is preferred because of its high multiplication rate and thereby converts the organic matter into vermicompost within 45-50 days. Since it is a surface feeder it converts organic materials into vermicompost from top.
Types of vermicomposting
The types of vermicomposting depend upon the amount of production and composting structures. Small-scale vermicomposting is done to meet the personal requirement and farmer can harvest 5-10 tonnes of vermicompost annually. Whereas large-scale vermicomposting is done at commercial scale by recycling large quantity of organic waste with the production of more than 50 – 100 tonnes annually.
Methods of vermicomposting
Vermicromposting is done by various methods, among them bed and pit methods are more common. In Bed Method composting is done on the pucca / kachcha floor by making bed (6x2x2 feet size) of organic mixture. This method is easy to maintain and to practice.
Whereas in Pit Method the composting is done in the cemented pits of size 5x5x3 feet. The unit is covered with thatch grass or any other locally available materials. This method is not preferred due to poor aeration, water logging at bottom and more cost of production.
Process of vermicomposting
Vermicomposting unit should be in a cool, moist and shady site and following steps are followed for vermicompost preparation. Cow dung and chopped dried leafy materials are mixed in the proportion of 3:1 and are kept for partial decomposition for 15 to 20 days, a layer of 15-20 cm of chopped dried leaves/grasses should be kept as bedding material at the bottom of the bed, the beds of partially decomposed material of size 6x2x2 feet should be made, each bed should contain 1.5-2.0q of raw material and the number of beds can be increased as per raw material availability and requirement.
The red earthworms (1500-2000) should be released on the upper layer of bed, water should be sprinkled with can immediately after the release of worms, beds should be kept moist by sprinkling of water (daily) and by covering with gunny bags/polythene; bed should be turned once after 30 days for maintaining aeration and for proper decomposition. The compost gets ready in 45-50 days and the finished product is 3/4th of the raw materials used.
Harvesting
When raw material is completely decomposed it appears black and granular. Watering should be stopped as compost gets ready. The compost should be kept over a heap of partially decomposed cow dung so that earthworms could migrate to cow dung from compost. After two days compost can be separated and sieved for use.
Preventive measures
The floor of the unit should be compact to prevent earthworms’ migration into the soil, 15-20 days old cow dung should be used to avoid excess heat, the organic wastes should be free from plastics, chemicals, pesticides and metals etc, aeration should be maintained for proper growth and multiplication of earthworms, optimum moisture level (30-40 %) should be maintained and 18-25 C temperature should be maintained for proper decomposition.
Nutrient content of vermicompost
The level of nutrients in compost depends upon the source of the raw material and the species of earthworm. A fine worm cast is rich in N, P, K, besides other nutrients. Nutrients in vermicompost are in readily available form and are released within a month of application.
Advantages
There are many advantages of vermicompost. It provides efficient conversion of organic wastes/crop/animal residues, it is a stable and enriched soil conditioner, helps in reducing population of pathogenic microbes, helps in reducing the toxicity of heavy metals, is economically viable and environmentally safe nutrient supplement for organic food production and is an easily adoptable low cost technology.
Dose Rate
The doses of vermicompost application depend upon the type of crop grown in the field/nursery. For fruit crops it is applied in the tree basin. It is added in the pot mixture for potted ornamental plants and for raising seedlings. For field crops the vermicompost at the dose rate of 5-6 t/ha, fruit crops 3-5kg/plant and Pots 100-200 g/pot can be used.
CONCLUSION
Cow dung is not waste, but a valuable ingredient that increases the profitability of dairy farms. While doing cost-benefit analysis the recurring expenditure in dairy farms is on account of Feed, Medicines and Supplements, whereas the output is in the form of Milk, Calves and the valuable Cow Dung!
But the dairy entrepreneurs and farmers have to realize the importance of cow dung, not let it go waste, and convert it into manure, preferably vermicompost. The farmers can not only use the vermicompost in their vegetable gardens but they can also pack it into bags for sale. The vermicompost is being sought by gardening lovers for growing ornamental indoor/outdoor flowering and foliage plants!
Dr. Zubair Ahmad War has done Masters in Livestock Production and Management (LPM)
Disclaimer: The views and opinions expressed in this article are the personal opinions of the author. The facts, analysis, assumptions and perspective appearing in the article do not reflect the views of GK.