@article{icrisat1804,
            year = {1999},
           title = {Assessing the Fertilizer Phosphorus Requirement of Grain Sorghum},
           pages = {1593--1601},
          author = {K L Sahrawat},
          volume = {30},
         journal = {Communications in Soil Science and Plant Analysis},
          number = {11/12},
             url = {http://oar.icrisat.org/1804/},
        abstract = {Two methods were evaluated for determining the fertilizer phosphorus requirements (FPR) of sorghum grown on a Vertisol under rainfed conditions. The first method was based on P on applied P uptake, and grain yield relationships for grain sorghum. In this method, P uptake at a given yield was determined from the relationship between total P uptake and grain yield. The amount of fertilizer P applied for the given P uptake and grain yield was then, determined from the relationship between P applied and P uptake. In the second method, FPR was determined using the equation: FPR=(Up-U0)/PRF, where Up is P uptake at a given yield, U0 is P uptake from unfertilized soil, and PRF is the recovery of applied P. The parameters, U0, Up, and PRF were determined in a field experiment in India. There was a good agreement between the observed value of FPR and predicted values determined by the two methods. These results suggest that the simple models based on P uptake can be utilized for determining the fertilizer requirements of crops.}
}