Effect of sowing and weed control methods on nutrient uptake and soil fertility in direct-seeded rice (Oryia sativa)

Abstract

A 2-year field experiment consisting of 3-planting methods and 5-weed control options was conducted in a three- time rcplicatcd split-plot design at Varanasi during kharif 20\ 6-17 to assess the nutrient uptake by direct-seeded rice (Oryza sativa L.) and available nutrient status of soil under different methods of establishing crop and managing weeds.Zero-till direct-seeded rice (ZT-DSR) + residue + Sesbania brown manuring (SBM) recorded lower density and dry-weight of weeds, higher organic carbon (OC), available N, P and K in soil and enhanced N, P and K uptake by 8.9,6.7,7.8% and 23.7,24.5 and 10.2% in grain and straw, respectively, over conventionally-tilled direct-seeded rice (CT-DSR) + SBM.Among weed control options, the use of pendimethalin (1000 g/ha)Jb chlorimuron + metsulftiron (4 + 4 g/ha, 25 DAS) + 1 HW (45 DAS) resulted in lower density and weeds, higher OC, available N, P and K in soil and improved N, P and K uptake in grain and straw by 23.6, 20.9 and 33.0 and 26.7, 25.5 and 26.6%, respectively over weedy check.However, higher EC andpH and lower nutrient (N, P and K) and protein content in grain and straw were found under weed-free condition.Overall, ZT-DSR + residue + SBM and application of pendimethalin (1000 g/ha)y& chlorimuron + metsulfuron (4 + 4 g/ha, 25 DAS) + 1 HW (45 DAS) proved better with respect to reduction in weed biomass, OC, available soil nutrients (N, P and K) and their uptake in DSR. © 2021 Indian Council of Agricultural Research. All rights reserved.