Studies on the nutritional requirements of a candidate rice genotype IR-6-25A evolved at NIA, Tando Jam

Field studies were conducted for two consecutive years to assess the nutritional requirements of newly evolved rice genotype IR-6-25A. The experiment comprising of seven fertilizer treatments with N applied at 90, 120 and 150 kg ha^-1 and P2O5 at 60, 90 and 120 kg ha^-1 with or without 25 kg ha^-1 ZnSO4 (36.4% Zn), was laid out according to RCB design with four replications. Paddy yield increased linearly with the increasing levels of N and P application. Zinc sulfate applied at 25 kg ha^-1 provided an additional harvest of 14-35% over their respective N and P applications. A significant antagonism between P and Zn absorption in plant was observed. Zinc concentration and uptake were significantly reduced due to increased P application; the reverse was true for P concentration and uptake. Dilution of Zn within plants occurred by increasing levels of N application.