Influence of fertilizers application systems on soil organic matter and agrochemical characteristics of the chernozem typical

The aim of the research was to establish the influence of organic, organo-mineral and mineral fertilizer systems of agricultural crops in field crop rotation on organic matter and agrochemical indicators of chernozem typical. It was established that during the period of conducting the stationary experiment (26 years) there was a decrease in the total content of humus in the soil within the arable layer by 0,05-0,62 % compared with the initial data. The application of additional carbon in the form of manure to the soil during organic-mineral and organic fertilizer systems helped to regulate the nitrogen-carbon balance in the soil by replenishing the reserves of carbon and nitrogen available for microorganisms, which led to anincrease in the humus content in the topsoil. The application of manure twice during the rotation of 40 t/ha contributed to an increase in the humus content by 7,2 %, and in the conditions of the organo-mineral fertilizer system - by 11,4 % compared with the control. The humus content is estimated as high and very high, the type of humus is humic, the degree of humification is high, the enrichment of humus with nitrogen is average. Proved that long-term use of mineral and organic fertilizers leads to acidification of the soil solution - a decrease in pHkcl parameters. The use of organic and organo-mineral fertilizer systems contributed to the accumulation of mineral nitrogen in the topsoil of typicalchernozem. The application of only mineral fertilizers enhances the mineralization of soil nitrogen, as evidenced by an increase in the content of ammonia nitrogen and a decrease in the nitrate content by 61,7 % compared with the control.