Вплив удобрення та вапнування на баланс і вміст форм калію в дерново-підзолистому ґрунті

Abstract

Goal. To determine the effect of plant by-products and mineral fertilizers in combination with different doses of dolomite flour on the balance and content of different forms of potassium in soddy podzolic cohesive-sandy soil. Methods. Field (the study of the effect of fertilization and liming on the change in potassium content in the soil), laboratory (the determination of the content of potassium forms in the soil), calculation (the assessment of potassium balance), statistical (the variance analysis of the reliability of research results). Results. The research during 2 rotations of a 4-field crop rotation established that liming 1.9–5.6 tons of dolomite flour with the subsequent annual entering into the soil of an average of 5 tons of by-products of crops in combination with the application of mineral fertilizers at a dose of N112P87K105 per 1 ha of the crop rotation area created the positive balance of potassium in the soil at its intensity of 167–206%. A rapid increase in the content of mobile potassium in the soil in these variants was observed only during the first 4 years of research, in subsequent years it varied within the reached level. Fertilization and liming had a positive effect on the content of all forms of potassium available to plants: water-soluble, exchangeable, and non-exchangeable. During 8 years of research, their content increased by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. Conclusions. The use against the background of liming and fertilization of by-products of crop rotation makes it possible to return to the soil 74.0–76.3% of the economic removal of potassium and, in combination with the application of 105 kg/ha of potassium with mineral fertilizers for 1 ha of crop rotation, to create a positive balance of the element at the level of 82.8–88.1 kg/ha. The content of mobile forms of potassium in the soil layer of 0–20 cm in the first 4 years of research in the variants with fertilizer increased from 53–57 to 89–102 mg/kg of soil, in the following 4 years it almost did not increase with certain variations over the years. Under the influence of the studied components of the fertilizer system in crop rotation, the content of all forms of potassium in the soil — water-soluble, exchangeable, and non-exchangeable — increased. Compared to the control, application of N112P87K105 per 1 ha of crop rotation area contributed to an increase in their content by 21.4 and 16.2%, respectively, for a combination of 3.8 t of CaMg(CO3)2 and N112P87K105 — by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. However, increasing the dose of dolomite flour from 3.6 to 5.8 t/ha in the crop rotation fertilizer system did not significantly increase the content of non-exchangeable potassium in the 0–20 cm layer of soddy podzolic soil.