Pre-plant and placement method for efficient use of P-fertilizer in wheat crop

Poor use efficiency of phosphorus is one of the major causes to lower the yield of wheat crop. Time and method of P2O5 application influence the degree of responsiveness. Therefore, an investigation was carried out under field conditions to compare three times (pre-plant, at 1st irrigation and at 2nd irrigation) and two methods (broad cast and placement) of P2O5 applications for wheat grown in three cropping zones (central, cotton and thal zone) of Punjab province of Pakistan. The division of zones is based on agro-climatic conditions and cropping pattern followed by the farmers. The hypothesis was made to suggest best time and method of P2O5 application in order to enhance its use efficiency. The experiments were chalked out by applying recommended dose of N, P2O5 and K2O @160, 114 and 62 Kg ha-1 in all treatments except control throughout study. The sources of N, P2O5 & K2O were Urea, Single Super Phosphate (SSP) and Sulphtate of Potash (SOP). Three, nine and one field trials were conducted during 2008-09 at framer’s fields in central, cotton and thal cropping zones of the Punjab province, respectively. It was found that time and method of P2O5 application significantly (P<0.05) affected the wheat grain yield in three cropping zones under study. Finally, our study suggested that application of P2O5 @ 114 Kgha-1 at the time of pre-plant with placement method produced the highest yield in central, cotton and thal zone as compared to all other times and methods of P-fertilizer application.