Effect of Exchangeable Sodium on the Yield and Chemical Composition of Raya (Brassica juncea L.)1

Abstract

AbstractLarge sodic areas of India are being brought under cultivation using gypsum as an amendment and by appropriate agronomic practices. Raya (Brassica juncea L.) is an important oilseed crop of the area, but virtually nothing is known about its tolerance to exchangeable Na. This study examined the effect of varying the exchangeable Na percentage on the yield and chemical composition of raya that was cultivated in the field. Raya was grown on plots that had been treated with graded doses of gypsum and subsequently cropped. At the time of planting, the soils (Aquic Natrustalfs) had attained ESP's of from 2.6 to 50.6 in the 0 to 15 cm layer and 20 to 90 in the 15 to 30 cm layer. Plant samples were analyzed and the oil content of seeds was estimated. Soil was analyzed for exchangeable Na and other chemicals. We found out that an ESP of more than 23 delayed germination, emergence of flowers and pods, but enhanced maturity. Grain and oil yield were significantly reduced above an ESP of 23.The decrease in the grain yield was associated with a Na content of 0.28% and a Ca:Na and K:Na of 3 in the stem at maturity. Sodium increased and Ca decreased with an increase in ESP; there was no effect on P and Mg content of the different plant parts. Potassium content at early stages of plant growth decreased with increase in ESP but was unaffected at maturity. Increasing soil ESP, in the range studied, did not affect the Fe, Mn, Zn, and Cu content of different plant parts.