Wheat, Lentil and Vetch Yield in Three Crop Rotations Under Different Tillage, Crop Residue Management and Nitrogen Fertilization in Mushagar

Ten years experiments were conducted on yield components of wheat, lentil and vetch in three different crop rotations under semiarid conditions of Central Jordan (Mushagar region). In each rotation three tillage practices, effect of three wheat crop residue management practices and three levels of nitrogen fertilizers were studied . In the two course rotation (wheat -lentil ) plowing with chisel followed by sweep early in the season before rain and incorporating the remaining wheat residue after baling and grazing ,as traditionally practiced, gave highest average grain wheat yield (1238 kg ha-1) and straw yield (3980 kg ha-1). Also addition of nitrogen fertilizer at 30 kg ha-1 produced significantly high grain (1208 kg ha-1) and straw (4249 kg-1) .Sweep plowing after rain yielded highly significant lentil grain yield (727 kg ha-1) . Straw yield has not affected by the studied treatments. In the three course rotation (wheat – lentil – melon) highest grain wheat yield (1803 kg ha-1) and straw (4658 kg ha-1) were obtained by plowing with moldboard followed by sweep before rain. Addition of nitrogen fertilizer, even at low rate (20 kg N ha-1) gave significantly higher grain wheat and straw yields than the control. Generally lentil yield components were not affected by tillage, residue and fertilization treatments. In the two course rotation (wheat – vetch) no significant effect for tillage and crop residue were observed on grain wheat yield, while nitrogen fertilization gave significantly high grain and straw yields (1054 and 3175 kg ha-1, respectively). Tillage by using sweep after effective rain gave significantly high vetch grain and straw yields (846, and 2754 kg ha-1, respectively). Seed bed preparation for wheat was adequate by using moldboard or chisel followed by sweep tillage, while sweep tillage only was proper for land preparation for lentil and vetch. Addition of nitrogen fertilizer (20kg ha-1) is important for wheat production, but not for the lentils and vetch, where residual nitrogen after wheat may be adequate as starter for N fixation and provide these legumes with its need of nitrogen.