Agroecological substantiation of meliorative factors for restoration of soils disturbed by military actions

Тhe armed aggression of the Russian Federation has led to the disruption of balance in agroecosystems in Ukraine. The purpose of this study was to investigate the agroecological consequences of soil disturbance in agrocenosis due to explosive ordnance and to justify the use of ameliorative factors for soil fertility restoration. Vegetation studies were conducted at the «Institute of Applied Biotechnology». Soil samples for the experiment were collected from the liberated territories of Kharkiv region affected by military actions. Soil expertise, disrupted by explosive ordnance, revealed changes in agrochemical, biological, and toxicological indicators compared to the control plot of the agrocenosis. The humus content decreased by 39–46%, hydrolyzable nitrogen by 30–38%, mineral nitrogen by 36–48%, while the availability of mobile potassium increased by 115–139%. Significant excess of heavy metals content in the soil was detected: copper content increased by 3 times, lead — by 1.5 times, nickel — by 2.7 times, and cadmium — by 2.5 times. Microbiological processes were characterized by an increase in mineralization-immobilization coefficients, oligotrophy, pedotrophy, and a decrease in organic matter transformation indicator. Based on the observed changes, ameliorative factors were proposed aimed at soil fertility restoration. The application of nitrogen-phosphorus mineral fertilizer, winter wheat straw as organic fertilizer, and the biological preparation EcoStern Detox contributed to the improvement of soil agrochemical properties and optimized the direction of microbiological processes, but had no systemic impact on the change in the quantity of mobile forms of heavy metals. The positive impact of amelioration on the soil environment was confirmed by bioassay. Combining the studied ameliorative factors resulted in a 14.3–18.1% increase in maize plant height at the BBCH 14 stage, an increase in aboveground biomass by 24–46.2%, and root mass by 13.3–14.3% compared to the control. The highest growth in the development of the photosynthetic apparatus and root system was observed with the application of the entire complex of ameliorants. The obtained results are consistent with the soil analysis, as the simultaneous application of the EcoStern Detox biopreparation, mineral fertilizers, and straw led to a significant improvement in both agrochemical and biological soil indicators compared to the control and other research variants.