Biological activity of typical chernozemic soil under different systems of main tillage and crops fertilisation of a short crop rotation

Abstract

The influence of four main tillage systems and four fertilization systems on biological reactivity of a plow layer of typical chernozemic soil under agrophytocenosis of five crops was investigated during four year research (2016–2019) of the stationary field grain row crop rotation. Loss of mass of flax linen in a plow layer of soil during two months of the study characterizing the intensity of cellulose-decomposing microorganisms under beard, beardless, differential and disc tillage made correspondingly 24.5; 22.7; 23.4 and 23.3 % – for soybeans; 16.3; 15.7; 15.9 and 16.2 % for winter wheat, 24.1; 22.8; 24.7 and 22.6 % – for sunflowers, 27.7; 24.1; 25.1 and 23.7 % – for spring barley, 21.9; 19.9; 22.4 and 19.0 % – for corn. Steady surface and beardless tillage strengthen the differentiation of a plow layer according to the intensity indices of flax linen decomposing while the beard one tillage decreases. The most heterogenic plow layer was observed under beardless tillage; it was a bit lower under disk tillage in a crop rotation. The intensity of flax linen decomposing on the top of a plow layer (0–10 cm) is the highest under beardless tillage and the lowest under beard tillage, while in the bottom (20–30 cm) of a plow layer an inverse relation can be observed. The intensity of carbon dioxide production by the soil under soybeans, winter wheat and spring barley is the highest under beard tillage and the lowest it is for soybeans under beardless and differential tillage, for winter wheat, sunflowers and spring barley under beardless tillage and for corn under disc tillage. For sunflowers and corn this index is higher under differential rather than under beard tillage in a crop rotation. The biological reactivity of a plow layer of a typical chornozemic soil increases as the fertilizers application rates increase. Crop rotation productivity is almost at the same level under beard and beard-beardless tillage in a crop rotation. Systematic beardless and surface disc tillage decreases this index significantly. Key words: soil, crop, crop rotation, tillage, fertilizers, flax linen, carbon dioxide, plow layer, heterogeneity.