RESPONSE OF WHEAT (TRITICUM AESTIVUM) TO NITROGEN FERTILIZATION UNDER VARYING TILLAGE AND CROP ESTABLISHMENT PRACTICES IN GREENGRAM (VIGNA RADIATA)-WHEAT CROPPING SYSTEM

摘要

Wheat grown under zero tillage (ZT) and raised-bed following a legume crop may have a variable N requirement compared with conventionally-tilled flat-sown crop. A field experiment was conducted for two years during 2005-07 to study the effect of varying tillage (conventional and zero), crop establishment (flat and raised-bed sowing) and N fertilization (0-160 kg N ha(-1)) on wheat grown after greengram at New Delhi, India. Rainy-season greengram performed equally well under flat and raised-bed planting, but the seed yield was 25.9% lower under ZT than conventional tillage (CT) conditions. Wheat following greengram during winter season also showed better growth and yield under CT than ZT, as well as under flat sowing than furrow-irrigated raised-bed (FIRB) system. The grain yield was highest under CT-flat, and decreased by 5.4-9.4% under FIRB system. Nitrogen fertilization up to 120 kg N ha(-1) under CT and 160 kg N ha(-1) under ZT increased grain yield, and the optimum doses were worked out to be 147.1 and 154.2 kg ha(-1), respectively. Nitrogen-use efficiency decreased with N levels but remained more or less similar under tillage and crop establishment practices. Maximum returns and B:C ratio were obtained under CT-flat, followed closely by ZT-flat.