Agrogenic changes in the redox potential in the profile of light-grey forest surface gleyed soils of the Western Forest-Steppe

Abstract

Goal. To study the change in redox potential (RP) in the profile of light-grey forest surface gleyed soil at different systems of fertilization and use. Methods. Field survey, physicochemical and comparative-analytical. Results. On the background of the calculated pHsalt and Clark index (rH2) the change was fixed in RP in the soil profile at long agrogenic impact. It was noted that durable plowing of the soil without fertilizers (control) for pHKCl 4,27 (average at 95% probability) led to the predominance in the profile of moderate- and low-acid mode. At entering N105P101K101 + 10 t/ha of manure + CaCO3 (1.0 Ng) on the background of changes in the reaction of the soil solution of pHKCl it was fixed sharp transition with depth of RP from intense oxidative (628 MB) to weakly recovered (363 mV) mode, and rH2 index amounted to 31,2–20,2. Conclusions. Use on acidic light-grey forest surface gleyed soil of organic-mineral fertilizer system in the dose of N105P101K101 + 10 t/ha of manure + CaCO3 (1.0 Ng) created the best conditions for the formation of intensive oxidation processes. Prolonged plowing of the soil without fertilization (control) caused the development in the profile of weakly oxidized processes. Systematic entering in the soil of some mineral fertilizers (N65P68K68) compared with the control and organic-mineral system of fertilizing contributes to a noticeable reduction of redox potential in the direction of the recovery processes. In order to study optimal doses of fertilizers and lime and to ensure balanced natural cycles of substances of acidic light-grey forest surface gleyed soils under different levels of agricultural loads, it is advisable to use RP as a highly sensitive performance indicator, which allows to quantitatively establish the deviation of the redox state of soil natural balance.