The influence of grain-beet crop rotation with different leguminous predecessors of winter wheat on the nutritive regime of typical chernozem

Abstract

Goal. To investigate the nutritive regime of typical chernozem in short grain-beet crop rotation with different legumes predecessors of winter wheat. Methods. General scientific and special. Agrochemical analyses were performed according to standard techniques. Results. The security of soil with easily hydrolyzing nitrogen for 11 rotations of 4-fields crop rotation did not depend on the predecessor of winter wheat and made 112–120 mg/kg of soil. There was a tendency to increase its content in the crop rotations with legumes predecessors of winter wheat. On average over the 14 years of research, the amount of mobile phosphorus in the topsoil was 122–137 mg/kg of soil. The highest content was in crop rotations with bare fallow — 137 mg/kg and fallow under vetch-oats mixture — 131 mg/kg soil. They observed an increase in exchange potassium content in the arable layer of soil in crop rotation with bare fallow. Its amount in the soil on average, before the harvest of barley, was greater on 14 mg/kg of soil than after other predecessors. In varients with legumes predecessors and corn for silage, they received the equal results — 115–119 mg/kg of soil. Conclusions. Compared to baseline data obtained during the laying of the experiment, research results for the period 1996–2009 had shown that prolonged use of short crop rotation improved the soil supply with nitrogen and phosphorus. On the contrary, the concentrations of these elements in the topsoil, the quantity of exchangeable potassium during this period had decreased. Most secured with phosphorus and potassium were crop rotation with bare fallow, with nitrogen and phosphorus — crop rotation with the vetch-oats mixture. Crop rotation with leguminous predecessors had the best ratio of nitrogen than that of crop rotation with bare fallow and corn silage.