Effect of Graded P Levels in Soils of Varying Available P Status on Yield and P Uptake by Crops

摘要

Field experiments were conducted to study crop response and removal of P by crops grown on soils of varying fertility status with graded levels of P application (0, 15, 30 kg P_2O_5 ha~(-1)) in soybean-wheat cropping sequence. Results indicate a significant increase in grain yield and P uptake by soybean and wheat at various levels of P and fertility status of soil. Grain yield and grain P uptake of soybean and wheat increased with increased level of P application in soils of both medium and high fertility status. Yield and P uptake was more on high fertility than that of medium fertility level of soil. But per cent increase over control of grain yield and P uptake by grain by both crops was more on soil of medium fertility than that of high fertility. Continuous cropping (Up to 9th crops) without P application decreased grain yield, P uptake of both crops and available P of soil. Soil initially high in available P can withstand P depletion due to cropping more than soils with low or medium available P status.