Restoration of degraded soils in a military-affected region in the South of Ukraine based on biologisation

Abstract

Background: This study was motivated by the need to restore soils degraded by military operations, accompanied by compaction,destruction of structure and contamination with heavy metals, which reduce the productivity and ecological functioning ofagroecosystems. The aim of the work was to evaluate the effectiveness of using microbial preparations and green manure cropsseparately and in combination to improve the condition of ordinary chernozem. Methods: The study involved a field experimentwith four treatment options: control; application of the “Azogran” biological preparation; green manure with a mixture of vetch andmustard; and a combination of these, and determination of the content of heavy metals in the soil and their biological activity.Results: The study found that the combined option provided the most positive changes: density decreased from 1.52 ± 0.03 to1.28 ± 0.02 g/cm3; the measured humus-related organic matter indicator increased from 2.1 ± 0.2 to 2.8 ± 0.1%; acidity changedfrom 5.8 ± 0.2 to neutral 6.7 ± 0.1; and the content of available, Chirikov-extractable phosphorus and potassium, reported asP2O5 and K2O, increased by 30.0 and 22.0%, respectively. Biological activity increased significantly: dehydrogenase activitydoubled, and basal respiration exceeded the control by 62.3%. It was also found that the concentrations of mobile forms of lead,cadmium, zinc and nickel decreased by 25.0–32.0%, which was accompanied by a 2.5-fold decrease in the phytotoxicity ofaqueous extracts. Conclusions: The data obtained demonstrate that the combination of the biological product with green manureresulted in synergistic improvements, simultaneously improving the physicochemical and biological properties of the soil andreducing the accumulation of metals. The practical significance of the study lies in confirming the possibility of using this approachas an affordable, environmentally safe and effective way to restore land damaged by military equipment.