The soil nutrient that plants required in greatest quantity is nitrogen. Despite its critical role in plant
nutrition, nitrogen is absorbed almost entirely in inorganic state, as nitrate or ammonium. However, the
bulk of nitrogenous materials found in soil or added in the form of plant residues is organic and, hence,
largely unavailable. The release of the bound element and the mobilization of the vast reservoir of
organically combined nitrogen are essential to the recycling of nutrient and therefore to soil fertility[11].
Furthermore, organic phosphorus in plant residues can not be directly absorbed by plants, which