Nitrates are readily dissolved in water and, because they are not retained by the soil, they can be lost. This process, called leaching, is most likely to occur in well-drained soils with resulting potential for groundwater pollution. Land application of nitrogen in concert with soil tests and crop requirements will minimize this potential. Nitrates can also be lost from the soil through a process called denitrification. This process takes place in soil saturated with water under anaerobic conditions.
Nitrate nitrogen is converted to nitrogen gases that are lost to the atmosphere.
Unless soils remain saturated for extended periods of time, nitrogen losses by this process are minimal. Phosphorus Phosphorus in manure is present in both organic and inorganic forms. However, published values suggest that 75-80 percent of manure phosphorus is available to plants in the year that the manure is spread. Phosphorus is the least mobile of the three nutrients in soil and, under certain conditions of low soil pH, phosphorus buildup in the soil may be noted. Because of the tendency of phosphorus to remain attached to soil particles, leaching to groundwater is not usually considered a problem.