You probably know that animal manures aren't just useless wastes. They can play an important role in maintaining or building soil fertility and productivity. But if you don't apply them properly or apply too much, you can pollute air, water and soil. Manure contains a number of essential plant nutrients, including nitrogen, phosphorus, potassium and micronutrients. Unlike commercial fertilizers, nutrients in manure vary greatly, depending on the type of livestock, the feeding practices and the met hod of manure collection and storage.
Manure is a slow-release fertilizer.
Organic nitrogen in the manure must be converted to an inorganic form before the crop can use it. This process, called mineralization, is controlled by soil temperature, moisture an aeration. Only about half of the organic nitrogen in manure is released to plants during the year of application. During the next two years, another 15-20 percent of the remaining organic nitrogen is slowly released. Unlike nitrogen, almost all of the phosphorus and potassium is available.