Intensity of microbiological processes in gray forest soils under the liming and plowing of crop by-products

Abstract

Established that liming with single dose by hydrolytic acidity (1,0 Hg) slows down the processes of organic matter mineralization in gray forest soil: without mineral fertilizers – in 2,1 times, with mineral fertilizers – in 4,1, with plowing of the seed crop biomass and the by-products of the predecessor – in 1,4 times. The mineralization of nitrogen compounds as a result of liming also proceeds slower: without mineral fertilizers – in 1,2 times, with mineral fertilizers – in 2,2 times. Confirmed patterns that were obtained in previous years of research about the impact of liming on the activity of humus mineralization – it decreases as a result of liming with full dose (1,0 Hg) without mineral fertilizers by 66,7 %, with mineral fertilizers – by 4,4 %.  The total biological activity in the soil without a mineral fertilizer increases as a result of liming by 23,0 %, with mineral fertilizers – by 42,5, at the background of exogenous organic matter (EOM) plowing – by 83,7 %. Liming allows to reduce the level of phytotoxicity of soil without mineral fertilization by 17,9 %, %, with mineral fertilizers at the background of EOM – by 12,2 %. Positive influence of liming is amplified in variants with introduction of organic matter into the soil (byproducts of predecessor and siderate). Plowing of siderate crop biomass and by-products of predecessor in crop rotation allows to slow down the processes of organic matter accumulation in soil. The application of liming and mineral fertilizers in combination with the introduction of EOM reduces the index of pedotropy in 2,1 times, only with mineral fertilizers (N60Р30К60) – in 1,5 times. Similarly, plowing of the EOM affects the intensity of other mineralization processes. The total biological activity increases as a result of EOM plowing into the soil: in the variant with the use of mineral fertilizers by 54,7 %, with mineral fertilizers and liming – by 28,9 %. Confirmed previously established laws regarding the impact of optimization of mineral nutrition on the activity of decomposition of humic substances: with an increase in the dose of mineral fertilizers in 1,5 and 2 times the activity of mineralization of humus decreases by 6.0 and 10,1 % respectively. With the improvement of mineral nutrition of plants, the amount of root extracts is increased, which is a more accessible substrate than humus acids, which leads to slowing down of the destruction of humus substances.