Effect of sulphur on prevention of iron chlorosis and plant composition of groundnut on alkaline calcareous soils

Abstract

SummaryA microplot experiment was conducted for two consecutive years, 1978–9 and 1979–80, on alkaline calcareous soils of Chittor, Kapasan, Nimbaheda and Chhotisadari blocks at the Department of Agronomy, College of Agriculture, Udaipur (India). It was found that soil application of 250 kg S/ha both of elemental sulphur and gypsum significantly increased chlorophyll a and b and concentrations of N, K and S of plants. Leaf sap pH and P and Fe concentrations were, however, significantly reduced by sulphur treatments. Foliar application of 0·2% Fe-EDDHA increased chlorophyll a and b and caused marginal increase in N concentration of plants. K and S concentrations remained unaffected but P and Fe concentrations underwent significant reduction. Leaf sap pH was not at all affected by this treatment.Failure of metabolic translocation of iron and hence its inactivation inside the plant is suggested to be the most probable cause for the incidence of chlorosis despite high tissue Fe concentration. Sulphur application created a balanced nutritional environment and thus kept iron physiologically active for chlorophyll synthesis. Reduced efficacy of Fe-EDDHA might be due to high P concentration in the plant.