Phosphate regime and phosphatase activity of degraded soils of agricultural lands of the Donetsk People’s Republic

The phosphate regime and the degree of availability of soils of agricultural lands with mobile phosphates were studied, and the phosphatase activity of the surveyed soils was determined as a diagnostic sign of the content of mobile phosphorus in the soil. The study was carried out on model sites of varying degrees of degradation located in the southern part of the Shakhtersky district of the DPR. A decrease in the content of mobile phosphorus was found in all model plots in comparison with the indicators of zonal soil. The most negative trend associated with a decrease in the content of this element relative to the control was noted in the arable horizon of plots 2, 7 (by 45.8–47.2%), which was due to the significant removal of mineral nutrition elements by crops forming a significant phytomass, such as Helianthus annuus L., Zea mays L. In the soils of sites 2 and 4, the maximum phosphatase activity was recorded, amounting to 210–346% relative to the indicators of the zonal soil, which was due to a lack of exchangeable phosphorus in the soil and additional release of enzymes by microorganisms and plants. The soils of most model sites 2, 4, 6, 7 were characterized by a “high” level of phosphatase activity, for sites 3 and 5, activity indicators were estimated as “average”. For all studied model sites, data were obtained showing a decrease in the content of mobile phosphorus and phosphatase activity with the depth of the soil profile.