The effect of nitrogen fertilizers and primary tillage on productivity of winter rapeseed in irrigated crop rotation in the South of Ukraine

The article presents the results of three-year (2010-2011 and 2013) experimental researches on the study of the influence of methods and depths of moldboard, subsurface and differentiated systems of primary tillage, different doses of nitrogen fertilizers on agrophysical condition of plow layer and productivity of winter rapeseed. It was determined that the most suitable soil for winter rapeseed cultivation according to the agrophysical qualities was the soil of the control variant with plowing at 25-27 cm. The nearest to the control in its effect on soil was the variant with the chisel plowing at 14-16 cm in the system of differentiated-1 tillage with one para-plowing per rotation. The researches revealed that the deep moldboard and differentiated-1 tillage contributed to the production of the highest seed yield during the application of nitrogen fertilizers in a dose of N 100-130 - from 2.56 to 2.65 t/ha.