Residual effect of organics and direct effect of mineral nitrogen on rice (Oryza sativa L.) in two different textural soils

Abstract

Nitrogen through organics and inorganics application is an alternate to maintain soil health and crop productivity in the rice cropping system. With this background, field experiments were conducted in farmer’s field at Kuttalam during 2012-2013, 2013-14 to evaluate residual organics and mineral nitrogen (100%N) on growth parameters and yield of rice (Oryza sativa) in sandy clay loam and clay loam soil. The treatments consisted of residual organics viz., composted coir pith (CCP), green manures (GM), sugarcane trash compost (STC), vermicompost (VC), poultry manure (PM) and FYM applied(100%N) and a combination of above residual organics with urea@50%N besides 100% recommended dose of nitrogen (RDN) and control. The results revealed that residual organics and urea recorded higher growth parameters like plant height, chlorophyll content, leaf area index(LAI), crop growth rate (CGR), relative growth rate(RGR), net assimilation rate(NAR), No. of tillers/hill compared to their individual addition. The growth parameters were more under residual PM in combination with mineral nitrogen in both the soils. Residual PM + fertilizer nitrogen (100% N) recorded highest grain (4485, 4693 kg ha-1) and straw yield (6984, 5897 kg ha-1) in clay loam and sandy clay loam soils, respectively. The lowest grain(3292, 2993 kg ha-1) and straw yield(4998, 4003 kg ha-1) were recorded in residual GM + fertilizer (100% N) in both soils. Among organics alone, residual PM(100% N) registered highest grain yield (4025, 4048 kg ha-1) in both soils. It can be concluded that the application of poultry manure alone or in combination with N fertilizers enhanced the growth and improved soil health.