Study of Microbiological Processes in the Soil of a Two-Year Fallow

A high degree of ploughing the soils is a destabilization factor of agrolandscapes and intensification of the erosion processes. Therefore, there arises a need to study the direction of the soil processes during the transfer of the arable land into a state of fallow. The state of microbiocenosis of a two-year-old abandoned land (fallow) was investigated using the gray forest soil in the variants of spontaneous overgrowth, sowing of grass mixtures and sowing of grass mixtures with simultaneous optimization of mineral nutrition of the phytocenosis as an example. It has been established that the least stable microbiocenosis is formed during the cultivation of the grass mixtures, which is characterized by the minimum total number of microorganisms (647.1 million CFU•g–1 of absolutely dry soil) and the minimum number of significant relations between the constituents (components) of the microbial community (98). The total number of microorganisms in the microbiocenosis of the spontaneous overgrowth variant and the legume-grass mixture exceeds that of the cereal grass mixture variant by 6.29 and 34.8%, respectively. A similar indicator for the total number of significant relations was 4.08%. Application of mineral fertilizers intensifies the process of mineralization of nitrogen compounds and slows down the consumption of the soil organic matter in the variants of sudden recovery of phytocenosis and cultivation of the legume-cereal grass mixture. The soil of the variant of the grass mixture is characterized by minimum total biological activity; it is 1.33 and 33.2% lesser than the total biological activity of the variants of spontaneous overgrowth and cultivation of the legume-grass mixture.