Abstract
A field experiment was conducted to study the effect of different application timings of P in
combination with Zn and P alone on rice at Adaptive Research Farm, Gujranwala, Pakistan during the
year 2010. The experimental treatments include: P application at the time of last puddling, P
application just before transplanting, P application 10 days after transplanting, P application 20 days
after transplanting, P + Zn application at the time of last puddling, P + Zn application just before
transplanting, P + Zn application 10 days after transplanting and P + Zn application 20 days after
transplanting. Different application timings of P in combination with Zn significantly reduced the
sterile percentage, when application delayed which resulted in more normal kernels as compared to
application of P alone and late one. Maximum abortive and opaque kernels were observed when P
application was done just before transplanting. Maximum chalky kernels were perceived when P+Zn
were applied 10 days after transplanting.Regarding concentration of P and Zn in rice straw and grain
significant difference was observed in all treatments. The highest Zn concentration in grain and straw
was observed in P + Zn application at 20 days after transplanting, while minimum Zn concentration
was observed in all treatments where P alone was applied in different timings. P concentration in
grain and straw was observed near seedling transplanting time more as compared to late applications
of P alone and in combination with Zn. It is concluded that Zn is essential nutrient for anaerobic rice.
More ever best timing for P application in rice crop is at time of last puddling. Combine application of
Zn and P in rice crop at the time of last puddling, resulted in higher yield.
