Content of labile forms and plant residues in cultivated soils

Abstract

The quick decrease of organic matter is a direct result of the sharp reduction of the biomass entering into the soil and quick mineralization of the organic matter in consequence of soil aeration after plowing. The rate of organic matter mineralization decreases till creation of an equilibrium state between the main processes – synthesis – decomposition. The influence of farming production and plant output on the content of labile forms and the need for plant residues to conserve and increase soil fertility of alluvial meadow soil (Eutric sandy and loamy), calcareous (Calcic chernozems (CHcc), leached chernozem (Haplic chernozems (Chha) and pseudopodzolic soil (Planosols (PL) cropped with wheat, maize and lucerne was studied in the 2018-2021 period in the Institute of Forage Crops. The obtained results were compared with those of virgin analogues of these soils. There is a marked tendency to increase of plant residues by 50-80% in all soils at both depths and detritus content by 40-60% in lucerne, as compared to wheat and maize, approximating and equalizing to that of virgin soil. Among the studied crops, lucerne conditions the lowest values of the C:N ratio in soils and in this connection it could be affirmed that it improves not only the humus composition, but also the nitrogen balance in all soils. The formation of higher fertility of the soils, on which lucerne is grown, is obvious.