Conservation agriculture, Nutrient uptake, Productivity, Residue retention, Weed interference

A field experiment laid out in a randomized complete block design with three replications was undertaken to evaluate the impacts of 12-year old conservation agriculture (CA)-based pigeonpea-wheat system on weeds and wheat during winter (Rabi) 2021-22. There were 10 treatments comprising of conventional till flatbed (CT), zero till (ZT) permanent narrow bed (PNB), broad bed (PBB), and flatbed (PFB) with (PNBR, PBBR, PFBR) and without residue (R). Residue retention treatments (PNBR, PBBR, PFBR) had 75% and 100% of the recommended N for wheat (i.e, PNBR75N, PNBR100N; PBBR75N, PBBR100N; PFBR75N, PFBR100N) during 2021-22. The CA-based permanent flat, broad, and narrow beds with anchored residue led to significant reduction in weed density and biomass at 60 days after sowing (DAS) and at harvest compared to ZT residue removal and CT treatments. These CA-based treatments considerably improved wheat growth indices, yield, and nutrient uptake. Among them, the CA-based PFBR100N and PBBR100N increased wheat grain yield by 14.1-15%, biological yield by 10.2-10.8% and total NPK uptake by 23-23.6% compared to CT and were most superior. The permanent beds with residue produced comparable wheat yields at 75%N and 100%N. Therefore, the permanent flat or broad bed with residue and 100%N in early years of CA adoption and 75%N in later years may be adopted for better weed control, higher crop growth and productivity of wheat in pigeonpea-wheat system.