Biomass and crop growth rate differ in rice genotypes with variable rates of phosphorus and zinc application

Field experiment was conducted to investigate the impact of phosphorus (0, 40, 80, 120 kg P ha-1) and zinc levels (0, 5, 10, 15 kg Zn ha-1) on crop growth rate (CGR) and total biomass yield (BY) of lowland rice genotypes [fine (Bamati-385) versus coarse (Fakhre-e-Malakand and Pukhraj)] in Northwestern Pakistan during summer 2011 and 2012. Higher CGR at various growth stages and total BY was obtained with the integrated use of higher phosphorus (80 and 120 kg P ha-1) and zinc levels (10 and 15 kg Zn ha-1). The lower CGR and BY was recorded when P and Zn were not applied (control) or when P and Zn were applied alone. In case of rice genotypes, the highest CGR and BY was recorded for Pukhraj than other two genotypes. The CGR was increased to the highest level at heading than at tillering and physiological maturity. The increase in CGR resulted in higher total BY. Increase in BY had positive relation with grain yield and growers income. It was concluded from the study that combine application of higher phosphorus and zinc levels to the coarse rice genotypes could increase CGR, total BY, grain yield and growers income in the study area.

Author : Amanullah1* and Inamullah