Published online by Cambridge University Press: 27 March 2009
Pod yield of groundnut and grain yield of wheat grown in that sequence was compared as affected by date of sowing and response to direct, residual and cumulative P application over 3 years in a field experiment. Total yield of groundnut and wheat was higher when groundnut was sown on 22 June and the following wheat on 1 November than when groundnut was sown on 6 July, followed by wheat sown on 16 November. Limited P requirement of groundnut was indicated by the small and inconsistent response to applied P on soil low in available P. Wheat responded to the second increment of P and direct application to wheat proved more effective than residual effects of previous application. Differential response of wheat to direct and residual P application in the groundnut-wheat cropping sequence indicates that P applications are more effective for wheat than groundnut, and groundnut can grow well on the residual P that remained in the soil.