Soil Respiration in Agricultural and Natural Ecosystems of European Russia

The results of the assessment of soil respiration in three regions-the Chuvash Republic and Ryazan and Kursk oblasts-are presented. Agricultural and natural ecosystems are divided into seven groups: croplands, pastures, hayfields, fallows, forests, stockyards, and open compost storages. CO2 emissions were measured in 2020-2022 using the chamber method. The rate of CO2 emission increased in the following order: croplands (0.03-0.24 g C-CO2/(m(2) h)) < pastures (0.07-0.33 g C-CO2/(m(2) h)) = hayfields (0.060.35 g C-CO2/(m(2) h)) = forests (0.07-0.28 g C-CO2/(m(2) h)) = fallows (0.08-0.37 g C-CO2/(m(2) h)) stockyards (0.21-8.61 g C-CO2/(m(2) h)) compost storages (1.15-13.85 g C-CO2/(m(2) h)). Estimates of CO2 emission from soils of pastures, hayfields, forests, and fallows did not differ statistically in most cases. The dependence of the soil respiration rate on hydrothermal (temperature and moisture content of the upper soil layer, air temperature) and agrochemical (contents of total carbon and total nitrogen and soil pH in the upper layer) indicators was analyzed for geographic regions and types of ecosystems. The most important factor both at the regional and ecosystem levels proved to be the soil temperature at a depth of 10 cm (r(p) = 0.41-0.88, p < 0.05). Moisture conditions did not play a significant role in the formation of the CO2 flux. On a regional scale, the content of carbon and nitrogen was important (r(p.) = 0.33-0.92, p < 0.05). This indicator depended more on the geographical location of objects than on the character of land use. The considered parameters contribute to 17-78% of the total variance of CO2 emission from the soils of the studied ecosystems.