Essay: Animal Waste in Sustainable Agriculture
However, in sustainable agriculture animals waste is used as tool for increasing yields in factory farming animals are kept in large numbers such that its waste becomes a problem to dispose. It is common to find animal waste mixed with water and stored in pits, in factory farming, which is later used for spraying the farming fields. This results in over-application of manure to the soil and more over the pits may leak thus mixing with running water.
Although manure is good for the soil, it is imperative to understand that it contains some pollutants. The antibiotics used on the animals ends up in to the manure, they cause problems to water animals, and plants if the contaminated manure runs in to water. Industrial dairies produce manure that is rich in salts, which are not good for maintaining quality of soil, and this can enhance erosion. Heavy metals present in animal waste include lead copper and zinc which is good for crops if applied in the right amounts, but over application causes reduced soil fertility. The damage that is caused by the effect of heavy metals is very hard to reverse. (Norberg-Hodge et-al 23-66)