Manure

Agricultural Uses

Manure is organic matter, either of vegetative or animal origin. It is spread or incorporated in soil for enhancing the nutrient value of the soil for the benefit of the plants.
Organic manure acts as a soil conditioner, increases water holding capacity of soil, maintains soil structure, provides nutrient fertility to the soil, and helps prevent soil erosion (through vegetative manure like litter, straw, green clippings) Animal manure is the oldest known fertilizer. It is a good way of disposing large quantities of animal waste created in farms. Commonly used animal manures are horse manure, sheep manure, cattle manure, pig manure, poultry manure and fish manure. Manures of different animals are often suitably mixed for use in specific crop and soil conditions. For example, pig dung is considered suitable for dry and hot conditions, whereas a mixture of cow dung and poultry dung is considered an ideal manure for rapeseed, lupines, peas and flowering plants. Cow manure is the most basic manure, generally accounting for the largest proportion in a manure mixture. Cattle manure has 0.55 % K and is required in quantities of 110 kg per 100 sq m.
Horse manure is coarse, light and dry. It is only half as dense as other manures and is regarded as a fast acting substance to stimulate growth. It is generally added to cow manure or in combination with other manures. Horse manure contains 0.65% N, 0.25% P and 0.5% K. If incorporated exclusively, around 9 1 kg are required to be added to 100 sq m area.
Sheep manure is considered most effective among the non-poultry manures, since it promotes quick growth of crops. It can be dried, bagged and sold. It contains 1 % N, 0.75 % P and 0.40% K. Ideally, 90 kg of this manure is required to be spread over a 100 sq m of land. Cattle manure is cool, wet and restrained and decomposes more easily than horse manure. It also has less nitrogen loss compared to that from horse manure.
Pig manure is wet, runny, cold and slow acting. But compared to horse manure, the nitrogen loss is less, and rotting is faster. The nutrient value is 0.5% of N, 0.3 % of P and 0.45 % of K. But larger quantities of around 100 kg are required to be spread or applied per 100 sq m of land.
Poultry manure is acrid and considered the most effective manure. The dry matter content is twice as much in cattle and pig manure. The phosphorus content is between 1 and 2 % which is considered quite high. The constitution of each manure and its nutrient value depend on factors such as fodder, the age of the animal, the collection and storage system and processing methods utilized, the animals chosen, the species of each animal, etc.
Manures can be used on the field either in its fresh form or after processing. Some types of manures can be made are warm manure, cold manure, farmyard manure, deep litter, slurry manure and compost. The basis of each type is to use different components of manure, to minimize the nutrient loss and change the kind of decomposition process, as necessary.
Warm manure is a manure system that combines aerobic and anaerobic decomposition in the manure heap. Cold manure system is based on anaerobic decomposition. Slurry manure is a mixture of all the components of manure, like excreta, urine, wasted feed and water, straw, etc. In the deep litter system of manure making, litter is allowed to collect on a straw mat on which animals walk. This manure becomes compacted. Farmyard manure (FYM) is a type of manure made from feces and other solid waste, like straw, bedding, plant waste, etc. Generally, this manure mix is stored in heaps to which fresh inputs are added. Important parameters in manuring are the time of application, machinery used and the method of manure application.
Nutrient efficiency of manure depends on the time of application and the surroundings. Adding manure just prior to seeding is a common practice. Since manure nutrients are released gradually, the application of manure at this time provides a nutrient supply during the growing season of the crop. Spring application is considered ideal. In summers, a manure application helps pasture and hay. The application of manure is not advised during or even just prior to rains, or even in autumn because of the risk of soluble nutrients being leached out. A winter application in very cold zones is not ideal, since nutrients cannot soak into a frozen soil.
In so far as tools for applying manure are concerned, deep plowing equipments can prove detrimental; light cultivators and one-pass tillage equipment are recommended. This is because both micro-organisms and oxygen are abundant in the upper layers of the soil. The combined action of these two ingredients can effectively process manure for the benefit of crop and soil. Solid manure needs to be crushed before being distributed. Liquid manure may be spread through high pressure nozzles.
Manure distribution is best done by the incorporation of manure straight into the soil. This method is preferred over the broadcast method for a number of reasons. If manures are spread on the surface, they increase the risk of disease to grazing animals, and also the loss of nitrogen. Surface application also promotes surface rooting of plants which is not beneficial for the crop. Incorporation of manure, done in the upper layers of the soil helps to restore soil moisture. Adequate manure and soil moisture encourage the activity of fungi and bacteria. Manure also keeps the soil aerated.
Manure can be processed into compost. Among the various innovations in compost making is biodynamic compost preparation. Rudolf Steiner is considered among the first to have initiated the thinking on enriching plants and soils with properties that are inherently prevalent in some natural plant materials (like flowers, barks, etc) Some examples of such recommended plant parts are Yarrow flowers (Achillea millefolium), wild camomile, stinging nettle, oak bark (Quercus robur), dandelion, and valerian. These materials are believed to improve the relationship between N and P in the soil, reinforce the soil's relation with Ca, impart good health to the soil, restore a good soil structure, prevent plant diseases, encourage a right relationship between Si and K, etc.