SOIL ORGANIC MATTER AND ITS GROUP COMPOSITION IN VARIOUS CROP ROTATIONS IN NORTHERN KAZAKHSTAN

Abstract

The article presents the results of research on changes in the content of organic matter in the soil and its group composition, during the cultivation of wheat by different precursors, in crop rotations with the plowing of sideral culture, 6-field and crop rotations. The research was carried out at the station of “SPC GF named after A.I. Barayev” LLP, on the southern carbonate black soils of Northern Kazakhstan, for three years. The lowest humus content in the soil was typical for the crop rotation (2.90-2.97 %). The use of mineral fertilizers in the crop rotation and the sealing of plant residues in the sideral crop rotation allowed maintaining the humus content in the soil at a stable level (3.06-3.13 %). The content of labile humus and humic acids in the soil of different variants of the experiment did not change significantly during the research period. According to the ratio of humic and fulvic acids, the type of soil humus was characterized as humate on average, ranging from 1.86 to 1.90 during the research, the humus content in the soil did not decrease, but remained at the same level. On variants without fertilizers, with the smell of sideral crops, the humus content was maintained at the same level, with the use of perennial herbs, the organic matter decreased, but not significantly. Keywords: humus, labile humus, humic acids, fulvic acids, crop rotations.