Biological indicators in the environmental monitoring of gray forest soil of agrosystems

Abstract

The objective was to monitor the biological indicators to assess the ecological sustainability of gray forest soil, due to the different level of agrotechnical burden on agricultural landscapes. During 10 years of research (2011-2020) the number of bacteria using various forms of nitrogen was continuously decreasing on the background of mineral intensification. The total average pool of active microflora on organomineral and mineral backgrounds in moulboard plowing was 20.1 and 16.1 million CFU g-1 of soil, respectively, during the period of observations. In non-moldboard plowing, the same average pool was 18.8 and 15.9 million CFU g-1. The minimum pool was maintained on a high-intensity mineral background in moldboard plowing, amounting to 14.5 million CFU g-1 of soil. The decrease in the total bacterial number in the soil of mineral backgrounds indicates a deterioration in their ecological stability. The calculated ecological and trophic indices indicate less ecologically stable low-intensity mineral background in moldboard plowing. This variant showed relatively low values of humus accumulation coefficients (Ch = 0.39) and transformation of organic residues into soil organic matter (Ct = 5.4) established at the highest mineralization coefficient (Cm = 1.57). In this soil, mineralization of organic matter prevails, which reduces its fertility and environmental sustainability. On this background, the activity of the studied enzymes was lower than in other variants and in the soil deposits. A set of micromycetes has shown to grow on mineral intensification backgrounds, especially on a high-intensity mineral background, where moldboard plowing was used as the main treatment. The lowest phytotoxicity was noted on a high-intensity organic-mineral intensification background –21.4%. Both microbiological and biochemical parameters represents an informative diagnostic feature of the ecological state of agrolandscapes. They ensure an objective assessment of the efficiency and degree of agrotechnical burden, predicting a decrease in environmental sustainability on mineral intensification backgrounds.