Effect of phosphorus application on wheat and rice yield under wheat-rice system

Abstract

A field experiment was conducted to study the response of wheat and rice to phosphorus during 20004-05 at D.I.Khan. The basal dose of N at 120 kg and K2O at 60 kg ha -1 was applied with P levels (0, 45 and 90 kg P2O5 ha ) to both wheat and rice crops. Wheat variety Naseer 2000 and rice variety IRRI-6 were used in the study. The experiment was carried out in RCB design with three replications. Phosphorus application significantly increased the grain yield of wheat from 2920 kg ha in control to 3560 kg ha in the treatments receiving P at 90 kg P2O5 ha -1 giving an increase of 22 % over control. The number of tillers, spikes, spike length and plant height of wheat were also significantly increased by P application. The rice also showed positively response to P application and hence both yield and yield parameters were significantly greater in the P than in the check treatment. Paddy yield was increased significantly by P application up to 75% over control. Plant height and 1000 grain weight were also significantly increased with P application over control. The application of P significantly increase number of spike plant and spike length over control, however no statistical difference was recorded among the treatment. The cumulative application of 90 kg P2O5 ha -1 gave the highest increase of 75% while direct application of the same level gave an increase of 54% however 47% increase over control was recorded by the residual application of 90 kg P2O5 ha . The highest VCR of 3.7:1 was achieved with the cumulative application of 45 kg P2O5 ha .