Effect of exchangeable sodium percentage and presubmergence on yield and nutrition of rice under field conditions

Summary The effects of exchangeable sodium percentage (ESP) levels of 82, 72, 65 and 35 and 0, 15 and 30 days of presubmergence (submergence prior to the transplanting of rice) on yield and chemical composition of rice and availability of Fe, Mn, Zn and P in soil were studied factorially in a field experiment. Presubmergence increased rice yields at all ESP levels, the effect being more pronounced at high ESP's. Increasing ESP decreased yields and the contents of Ca, Mg, K, Fe, Mn, Zn and Cu but increased that of P and Na in the crop. Presubmergence enhanced absorption of all the above elements by the crop except P, K, Mg, Zn and Cu in the grain and decreased Na in grain and straw. Growing of rice under submerged conditions also facilitated the improvement of these soils. Effects of submergence and ESP on the availability of Fe, Mn, Zn and P in soil and their role in the nutrition of rice are discussed. The results suggest that 15 to 30 days presubmergence improved rice yields on a calcareous sodic soil of the Indo-Gangetic alluvial plain.