Optimization of reclaimed land fertility agrophysical indicators of the verkhnevolzhie through basic tillage in corn cultivation
The paper presents the results of research on the influence of not uniform depth of moldboard and boardless cultivation on agrophysical indicators in the basic soil preparation system in the corn cultivation on the reclaimed lands of the Upper Volga region during three rotations of the 4-field crop rotation. Investigations were carried out in 2004-2016 in the test site of Agroflrm «Dmitrova Gora», OJSC, Konakovsky District Tver Region. As an object of analysis the corn hybrid PR-39B x29 was used, it belongs to the first group of early maturity in accordance with the FAO classification, and in the Upper Volga region condition stably reaches middle dough stage of the corn on the cob in the first half of September. The thickness of the arable layer is 20... 22 cm; humus content 1.62-1.78%; easily hydrolyzed nitrogen 72-78 mg; Р<sub>2</sub>О<sub>5</sub> - 155-182 mg; K<sub>2</sub>O - 93-104 mg/kg of soil;pH<sub>solt extract</sub> - 5.8-5.9. It has been established that moldboard plowing at 30 cm significantly improves the structure of the topsoil only, up to the level of a plowed furrow. Therefore, in order to fundamentally improve the reclaimed land structural condition during moldboard implements cultivation should be used subsoil plowing. Disk plowing and deep chisel plowing at the beginning of the corn growing season ensure the maximum supply of productive moisture in all soil layers compared to plowing to a depth of20 (control) and 30 cm, but at the beginning of the field crops growing season productive moisture corresponded to the optimum value for all basic soil cultivation methods.