relation: http://oar.icrisat.org/1804/ title: Assessing the Fertilizer Phosphorus Requirement of Grain Sorghum creator: Sahrawat, K L subject: Sorghum description: 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. date: 1999 type: Article type: PeerReviewed format: application/pdf language: en identifier: http://oar.icrisat.org/1804/1/ComSocSciPlantAnal30_11-12_1593-1601_1999.pdf identifier: Sahrawat, K L (1999) Assessing the Fertilizer Phosphorus Requirement of Grain Sorghum. Communications in Soil Science and Plant Analysis, 30 (11/12). pp. 1593-1601. relation: http://dx.doi.org/10.1080/00103629909370311