Effect of Prescription-based Fertilizer Application on Different Fractions of Phosphorus under Wheat in an Acid Alfisol

摘要

Phosphorus (P) is a critical element in agricultural ecosystems throughout the world. It is one of the limiting nutrients in acidic soils which have high P fixing capacity due to high Al and Fe oxide concentrations. Its mobility is strongly affected by its reactions with soil constituents. Many attempts have been made to explain the sequence of reactions that leads to phosphate retention in acid soils (Borling et al. 2004; Allen and Mallarino 2006). Mostly, P added through mineral fertilizers to these soils got fixed by reactions with Fe and Al compounds and is transformed into relatively insoluble P compounds. Soil P availability can be increased due to continuous application of P in soil (Lai et al. 2003; Zhang et al. 2004). The P use efficiency,in acidic soils is generally low around 10-15% (Sharma et al. 2002). Application of FYM over a long period might influence forms and availability of P due to release of organic acids and other microbial products which modify soil pH during decomposition.The availability and fractions of soil P may also get affected due to long-term continuous P fertilization.