Effect of conservation tillage and phosphorus levels on weed growth and wheat productivity in rice-wheat cropping system

A field study was conducted during 2019-20 and 2020-21, to assess the effect of crops residue management, tillage and phosphorus on weeds growth and wheat productivity in rice-wheat cropping system. The weed density and biomass were significantly lower under zero-tillage (ZT) wheat grown in sequence with puddled transplanted rice (PTR) and rice residue retention as compared to rice residue removal or burning. Wheat plant height and tillers density were significantly influenced by residue management. Highest grain yield of wheat was attained in ZT-wheat with rice residue retention and in sequence with PTR with wheat residue. Wheat grain yield was 17.3 and 15.8% higher than conventional tillage-wheat without rice residue, and 12.8 and 11.7% higher in comparison to ZT-wheat grown after partial burning of rice residue, during 2019-20 and 2020-21, respectively in sequence with PTR without wheat residues. Wheat growth and yield enhanced significantly with increase in phosphorus (P) level from 0 to 60 kg/ha, across the residue management practices but weed density and biomass were unaffected. ZT-wheat with rice residue grown in sequence with PTR with wheat residues did not respond to phosphorus application and recorded similar yield with all tested doses of P. Thus, conservation tillage improved wheat productivity and reduced cultivation cost by reducing usage of fertilizers and herbicides.