DIRECTION OF MINERALIZATION-SYNTHESIS PROCESSES OF ORGANIC MATTER IN LEACHED CHORNOZEM UNDER VARIOUS FERTILIZATION OF SPRING BARLEY

Abstract

Objective. To investigate the direction of mineralization-synthesis processes of organic matter in the soil during the cultivation of spring barley in different agrobackgrounds using new methodical solutions. Methods. Field experiment, gas chromatography (to determine the emission of nitrous oxide and carbon dioxide), statistical. Results. The study of the emission of nitrous oxide and carbon dioxide and subsequent calculations of the specific losses of N-N2O (g/kg С-СО2) depending on the fertilization systems and in comparison with the parameters in the “reference” soil (fallow) provide an opportunity to quickly determine the direction of mineralization-synthesis processes of organic matter in the soils of agrocenoses. Under the conditions of a stationary field experiment on leached chornozem during the cultivation of spring barley in crop rotation, it was shown that the use of mineral fertilization systems leads to the initiation of mineralization processes, the intensity of which increases with an increase in the rates of fertilizers. The application of mineral fertilizers against the background of the first year aftereffect of organic matter (5 t/ha of straw + 13 t/ha of the mass of intermediate lupine green manure) significantly improves the situation. At the same time, when using the lowest (N30P30K30) and medium (N60Р60К60) doses of mineral fertilizers in the experiment against the background of the aftereffect of organic fertilizers, the soil is characterized by the dominance of organic matter synthesis processes. The highest rate of fertilizers in the experiment (N90Р90К90), even if it is used against the background of the aftereffect of straw with lupine green manure biomass, leads to the activation of mineralization processes. Under the aftereffects of cattle manure, lupine green manure and their combination, including with mineral fertilizers, there is a slight predominance of mineralization activity over immobilization activity. Conclusion. The use of the gas chromatography in finding out the direction of mineralization-synthesis processes of organic matter makes it possible to quickly determine the ecological expediency of crop fertilization systems. To optimize the course of processes, it is advisable to combine the use of mineral fertilizers against the background of organic ones.