Changes in Forms of Phosphorus : Under Continuous Rainfed Maize-Wheat Cropping System in Low Hill Zone of Himachal Pradesh

Long term fertilizer experiment studies has revealed that due to continuous use of nitrogenous fertilizers, the pH of soil and available P status decreased significantly from the initial status. The transformation of added phosphorus greatly depends on the physical and chemical environment of the soil and pH is one of the factors which affect its transformation as the ionic forms of inorganic P are pH dependent. As P is second most important nutrient after N for plant growth, hence, understanding the transformation and distribution of various forms of P in soil receiving continuous fertilizer and manure application is essential in developing appropriate P management strategies for sustainable agricultural production. To fulfill this purpose, present study was designed to study the effect of long-term application of chemical fertilizers and organics on changes in forms of phosphorus in rainfed maize-wheat system.