Response of rice to zinc application and evaluation of critical levels of zinc in deltaic rice soils of Andhra Pradesh

摘要

Pot culture and laboratory experiments were conducted to study the effect of zinc application on yield and uptake of Zn by rice and to find out suitable extractants for extraction of Zn from deltaic rice soils. The yield of rice significantly increased with the application of Zn upto 10 ppm. Zinc concentration in plant tissue and zinc uptake by grain and straw also increased significantly with the Zn application. A level of 0.84 ppm 0.01 M EDTA extractable Zn, 0.875 ppm neutral N NH_4OAc + 0.01 percent Dithizone extractable Zn and 0.75 ppm DTPA extractable Zn in soils were found to be critical, below which response to Zn application is expected, where as 31.0 ppm, 24.45 ppm, 15.50 ppm and 20.02 ppm Zn concentration was estimated to be critical at tillering, flowering, grain and straw, respectively. Simple correlation studies indicated significant and positive correlation of all tile extractants with Bray's percent yield, tissue zinc, zinc uptake at tillering and flowering stages.