Sofia Yurievna Nesterkina

The paper evaluates the effect of erosion processes on the agrochemical and microbiological properties of the soil in different seasons of the annual cycle. The objects of the study are agro-gray soil of varying degrees of water erosion (uneroded, slightly and moderately eroded) and gray soil under woody forest plantations (south of the Moscow region). It was found that the content of alkaline hydrolyzable nitrogen, exchangeable potassium and mobile forms of phosphorus in the soil depended both on the degree of soil erosion and on seasonal fluctuations. Analysis of the chemical composition of soil organic matter showed that in the summer there was an increase in carboxylic, carbonyl and aromatic components, and in other periods – carbohydrate fractions. In the agro-gray soil, bacterial biomass stocks ranged from 27 to 96 kgha‒1, fungal biomass – from 10 to 357 kgha‒1, their dynamics were determined to a greater extent by the degree of washout and to a lesser extent by the season. With an increase in the degree of washing, both fungal and bacterial biomass decreased in the series unwashed>slightly washed>medium washed. Washed-away soils lost an average of 50% of bacterial and 59% of fungal biomass relative to non-washed soils. In the gray soil, bacterial biomass stocks varied seasonally from 43 to 107 kgha‒1, and fungal biomass from 171 to 621 kgha‒1. The gray soil under forest was superior in microbial pool to all variants of agro-gray soil, and was also characterized by a high content of mycelium, both actinomycete and fungal. In the studied soils, the level of potential respiration (SIR) exceeded the level of actual respiration (BR) by 2‒33 times. Microbial biomass reacted most actively to the introduction of glucose in the average washed soil in the spring and summer periods.