Changes in Agrochemical Properties of Sod-Podzolic Soil and Productivity of Grain-Grass Crop Rotation Depending on Nutrients Balance

Abstract

In a stationary field experiment on soddy-podzolic light loamy soil, the influence of fertilizer systems (organic, mineral, organo-mineral) and liming on the balance of nutrients, changes in the agrochemical parameters of the soil and the productivity of grain-grass crop rotation was studied. At the end of the 1st rotation of the five-field crop rotation, a medium-strength correlation (0.51) was revealed between the potassium balance and the change in its content in the soil, determined in an extract of 0.2 n. HCl (according to Kirsanov method). It was established that liming at 1.0 Ha of slightly acidic soil increased the productivity of crop rotation by 10%, which in turn led to an increase in the removal of nitrogen, phosphorus and potassium with crop yields by 10-14%. A positive balance of phosphorus was achieved only in the variant with an organo-mineral fertilizer system when applying manure and mineral fertilizers in full dose. It should be emphasized the need to take into account the return of nutrients with straw, in case of plowing in the field. It was revealed that in the organo-mineral fertilizer system, the share of biological nitrogen entering during the plowing of the clover layer is 26-28%, and about 20-23% more N is supplied during the plowing of straw. It was noted that when calculating the nitrogen balance, it is necessary to take into account its supply not only with mineral fertilizers, but also due to biological nitrogen fixation, when incorporating straw, etc. Failure to take into account these sources can lead to serious miscalculations. The organo-mineral system provided the highest productivity of the grain-grass crop rotation - 5.16 t of grain units/ha on an unlimed background and 5.73 t of grain units/ha with liming. On a slightly acidic background, the organic and mineral fertilizer systems ensured an equal crop rotation productivity of 4.28 t of grain units/ha, while liming had a slight advantage for the mineral system.