Changes in humus content and physicochemical properties of typical chornozem depending on cultivation and mineral fertilizer systems

Abstract

Goal. To determine the influence of tillage and mineral fertilizer systems on humus content and reserves, changes in the physicochemical properties of typical low-humus chornozem in short crop rotations. Methods. Field — to determine the interaction of research objects with natural and agrotechnical factors; laboratory — to determine humus content, pHsalt, amount of absorbed bases, hydrolytic aci­dity, the content of exchangeable cations; statistical-mathematical — to conduct dispersion analysis and statistical processing of research Results. Results. The research (2019–2022) showed that the use of a typical chornozem cultivation system against the background of minimized mineral fertilizing (N16P16K16) in a layer of 0–20 cm contributed to an increase in humus content at plowing by 12%, disking — by 8.9, use of no-till technology — by 0.25%, compared to the control (without fertilizers). Against the background of intensive mineral fertilization (N90P90K90), humus reserves in the soil layer of 0–20 cm increased by 7.1 t/ha with plowing, 6.0 t/ha — with shallow disc tillage, and 6.8 t/ha — with no-till technology compared to the control (without fertilizers). For carrying out shallow disc tillage and using minimized mineral fertilizing (N16P16K16), optimal indicators of the amount of absorbed bases in the soil layer of 0–20 cm were noted compared to indicators of the amount of absorbed bases for plowing and no-till technology. The largest losses of exchangeable cations (Ca2+ and Mg2+) against the background of intensive mineral fertilization (N90P90K90) using no-till, disking, and plowing technologies were determined. The highest values of hydrolytic acidity (3.06 m·equiv./100 g of soil) were recorded when intensive mineral fertilizing was applied in the 0–20 cm layer for plowing, the lowest values were in the 20–40 cm layer for no-till technology. Conclusions. It was determined that the content of humus in the arable layer of typical chornozem increased due to shallow disc tillage against the background of minimized mineral fertilization (N16P16K16) compared to the content of humus during plowing and no-till technology. It was proved that the system of cultivation of typical chornozem under intensive mineral fertilization (N90P90K90) had no significant effect on the number of absorbed bases. It was established that intensive mineral fertilization had a significant effect on exchangeable cations (Ca2+ and Mg2+) and indicators of hydrolytic acidity in typical chornozem for all treatments carried out.