THE EFFECT OF MINERAL NITROGEN FERTILIZERS ON THE CONTENT OF NUTRIENTS IN THE SOIL DURING THE CULTIVATION OF WINTER WHEAT IN VARIOUS CROP ROTATIONS IN THE CONDITIONS OF THE DRY STEPPE ZONE OF WESTERN KAZAKHSTAN

Abstract

Nutrients are the most important element of soil fertility, which determines the productivity of agricultural plants. The system of application of fertilizers, methods of tillage, selection of crops in crop rotation and other agronomic measures depend on their content in the soil. It is important to create conditions for the full use of nutrients from the soil that are in a state accessible to plants. The soils of the West Kazakhstan region have a relatively low content of available nitrogen. The amount of nitrogen depends not only on the size of the crop, but also on the quality of winter wheat grain. Nitrogen enters the soil as a result of mineralization of organic matter or its fixation by nodule or free-living bacteria. An additional nitrogen resource is the application of fertilizers. In a long-term stationary experiment in the West Kazakhstan region, the influence of crop rotations and mineral nitrogen fertilizers on the dynamics of the content of basic nutrients in soft winter wheat crops was studied. The experience was laid in 2006-2008 in the fields of the research institution limited Liability Partnership "Ural Agricultural Experimental Station". The studies were carried out in 3-full grain-steam, 4-full grain-steam, 4-full grain-tillage and 5-full grain-steam crop rotations. The soil of the experimental site is dark chestnut, heavy loamy, containing 3.0-3.5% humus in the arable horizon. The data of 3 years of studies of the dynamics of nitrogen content in layers 0-20, 20-40, 0-40 cm during the growing season of agricultural crops using mineral nitrogen fertilizers are analyzed.