Емісія CO2 з ґрунту за застосування органічних та органо-мінеральних ґрунтополіпшувачів

The results of field studies on the impact of applying organic and organo-mineral amendments on the dynamics of CO2 emissions during the growing season of grain corn and the content of organic carbon in the soil are described. A long-term (since 1989) small-plot experiment was conducted on podzolized low-humus heavy loamy chernozem on loess-like loam (Luvic Chernic Phaeozem) in the experimental farm of the National Scientific Center "Institute for soil science and agrochemistry research named after O. N. Sokolovsky” in the Kharkiv region in the conditions of the Left Bank Forest-Steppe. The experimental options include the composition, method, and doses of organic and organo-mineral amendments developed on the basis of leonardite with the addition of bentonite, molasses, and iron sulfate (and nitroammofoska in the organo-mineral) - 30 and 60 kg/ha in terms of nitrogen content. During the growing seasons of 2020 and 2021, we studied the seasonal dynamics of the following soil parameters: carbon dioxide emission intensity; organic carbon content; moisture content; temperature. Weather data taken from a weather station. CO2 emission measurements were carried out 4 times each year during the growing season using a portable testo 535 gas analyzer with isolation from atmospheric air. Within the arable layer (0-20 cm), the following were determined: the content of organic carbon in the soil by the oxidimetric method, the moisture content by the gravimetric method; the soil temperature measured with a Savinov thermometer. The results of the research have established a clear seasonal dynamics of the soil's ability to produce CO2 (from 0.1 to 2.0 kg/ha per hour) with a maximum in the spring and a gradual weakening by autumn, which is explained by the influence of weather conditions and the soil microclimate. A predictive model of the dependence of the intensity of CO2 emissions on the parameters of soil temperature and humidity is proposed. Compared to seasonal changes in CO2 emissions, the differences caused by the use of the two types of amendments are much smaller and manifest themselves mainly during the first half of the corn-growing season. The highest CO2 emission is with local application of organic amendment at a dose of 30 kg N/ha.The application of organic and organo-mineral amendment had a positive effect on the accumulation of organic carbon in the soil.The most effective method was recognized as the local method of applying a granular organo-mineral amendmentwith a C/N ratio of 5, in which the level of CO2 emission slows down compared to an organic amendment, and the total organic carbon content of the soil is the highest compared to other experimental options.It has been proven that carbon sequestration by soil, in addition to hydrothermal environmental conditions, is influenced by the composition and method of amendment, which can serve as a recommendation for the practical use of land improvement and fertilization agents in agriculture.