Tillage and weed control effect on weeds and wheat productivity

Abstract

A 3-year study was conducted to assess the impact of tillage and weed control practices on weed flora and wheat productivity. Experiments were conducted during Rabi season of 2012–13 to 2014–15 at GBPUA&T, Pantnagar, with clayloam soil. There were five crop establishment methods, viz. Transplanted rice (conventional tillage) (TPR)- wheat (conventional tillage) (CTW) (TPR-CTW), Transplanted rice (conventional tillage)- wheat (zero tillage)-Sesbania green manuring (S) (TPR-ZTW-S), Direct-seeded rice (conventional tillage)-wheat (conventional tillage)-Sesbania incorporation (S) (DSR-CTW-S), Directseeded rice (zero tillage)-wheat (zero tillage)-Sesbania brown manuring (S) (ZTR-ZTW-S) and Direct-seeded rice (zero tillage) + residue retention-wheat (zero tillage) + residue retention-Sesbania brown manuring (S) (ZTR + R-ZTW+R-ZTS) and three weed control methods [(weedy check, recommended herbicide (Recommended ready-mix herbicide clodinafop 15% + MSM 1% (60 + 4 g/ha) and integrated weed management i.e., clodinafop 15% + MSM 1% 60 + 4 g/ha fb manual weeding at 45 days after seeding (DAS)]. Continuous zero-till cropping system along with residue retention and brown manuring of Sesbania has resulted in the lowest total weed biomass at 60 DAS and greatly reduced the density of Phalaris minor, Medicago denticulata, Polygonum plebeium and Coronopusdidymus. However, density of C. didymus, Rumex acetosella and Vicia sativa was reduced under conventionally tilled wheat. Ready mix application of clodinafop 15% + MSM 1% supplemented with one hand weeding at 45 DAS greatly reduced the density and biomass of weeds. The maximum wheat grain (4.5 t/ha) and straw (6.3 t/ha) yields was achieved under zero-tilled wheat with rice residue retention and Sesbania as brown manure. The integration of clodinafop 15% + MSM 1% with 1 HW at 45 DAS resulted in an increase in grain and straw yields by 45.5% and 30.8%, respectively, over weedy check. It may inferred that in wheat cultivation conventional tillage could be replaced with zero-tillage along with residue retention by growing of Sesbania and the application of 2,4-D at 30 days stage to attain sustainability of ricewheat cropping system.