Evaluation of Critical Concentration of Zinc in Rice and Wheat Grown in Tarai Soils

A pot culture experiment was conducted to determine the critical Zn concentration in rice and wheat plant tissues for predicting response to zinc application. DTP A extractable Zn in soil was found to be significantly correlated with tissue Zn concentration in rice (r = 0.717**) and wheat (r = 0.851**). Also, tissue Zn concentration was significantly correlated with Bray's per cent yield in rice (r = 0.187**) and wheat (r = 0 558**). The critical Zn concentration in 52-day old rice and wheat plants below which responses to applied Zn may be expected, was 37 and 29 ppm, respectively. All the soils, in which the tissue Zn concentration in rice and wheat was below 37 end 29 ppm respectively, markedly responded to Zn application and rated to be Zn deficient soils.