From ancient times, Indian farmers have used cow dung, kitchen waste, and crop residues to improve soil fertility. These natural materials, called organic manures, are cost-effective, safe, and help grow healthy crops. In today’s farming, where chemical fertilizers are widely used, going back to organic methods can improve soil health and reduce pollution.
What Are Organic Manures?
Organic manures are made from waste materials like animal dung, crop remains, kitchen waste, and even certain weeds or green leaves. These materials break down slowly in the soil and release nutrients that crops need. They also improve soil structure, increase water holding capacity, and support the growth of useful soil microbes. Compared to chemical fertilizers, manures have less nutrients per kilogram, but their long-term benefits are higher.
Types of Organic Manures
Organic manures are generally grouped into two types: bulky and concentrated.
Bulky Organic Manures
These manures are applied in large amounts because they contain small amounts of nutrients. Examples are farmyard manure (FYM), compost, and green manures. They improve soil condition, provide nutrients over time, and help control harmful soil pests and diseases.
Farmyard Manure (FYM)
FYM is a mix of cow dung, urine, leftover straw, and bedding from animal sheds. A well-decomposed FYM usually contains 0.5% nitrogen, 0.2% phosphorus, and 0.5% potassium. However, current methods of collecting and storing FYM are not perfect. Urine, which is rich in nitrogen and potassium, is often wasted. To reduce nutrient loss, farmers can collect urine-soaked bedding and dung daily and place it in a trench. Once the trench is full, the top is covered with a mix of mud and cow dung and allowed to decompose for 4-5 months.
To further reduce loss of nutrients, farmers can spread gypsum or superphosphate in cattle sheds. These materials help absorb the urine and add extra nutrients like phosphorus and sulphur. FYM should be spread evenly in the field and mixed with the soil before planting. Usually, 10 to 20 tonnes per hectare is applied. For crops like vegetables and sugarcane, more FYM (over 20 tonnes) can be used, but it should be added at least 15 days before sowing.
Sheep and Goat Manure
Droppings from sheep and goats have more nutrients than FYM. They contain about 3% nitrogen, 1% phosphorus, and 2% potassium. These manures can be collected and decomposed before use or directly applied to the field by letting animals stay overnight and mix their waste with the soil.
Poultry Manure
Poultry droppings have high nitrogen and phosphorus. If not used quickly, a lot of nitrogen is lost within a month. It contains about 3% nitrogen, 2.6% phosphorus, and 1.4% potassium. This manure is very useful for crops that need more nutrients quickly.
Concentrated Organic Manures
These manures have higher nutrient content and are needed in smaller amounts. Examples include oilcakes, blood meal, and fish meal. These materials break down slowly but provide nutrients to crops over a longer time.
Oilcakes
Oilcakes are the leftover solid part after oil is extracted from seeds. Some oilcakes, like groundnut and coconut cake, are safe for animals, while others like neem and castor cakes are only used as manure. Before use, oilcakes should be powdered and applied 7–10 days before planting. This ensures better breakdown and nutrient availability. Oilcakes are especially useful for fruit and plantation crops.
Animal-Based Concentrated Manures
These include blood meal, meat meal, fish meal, horn and hoof meal, and bone meal. Blood meal contains the highest nitrogen content and is a good source of nutrients for crops. Meat and fish meals also provide a mix of nitrogen, phosphorus, and potassium. Bone meal is a rich source of phosphorus, useful for root development in crops.
Best Crops for Organic Manures
Crops like potatoes, tomatoes, sweet potatoes, carrots, radish, and onions grow well with FYM. Other crops like sugarcane, paddy, napier grass, bananas, mangoes, and coconuts also respond well to organic manures. However, all nutrients in manures are not immediately available. Only about 30% nitrogen, 60-70% phosphorus, and 70% potassium in FYM are used by the first crop.
Using organic manures is not just good for crops but also for soil and the environment. By using farm waste wisely, farmers can reduce their need for costly chemical fertilizers and improve their soil’s health. With proper collection, preparation, and application methods, organic manures can help increase farm income, especially for small and marginal farmers. Let us return to our traditional wisdom and make organic farming a strong part of our future.
