Soil Respiration in Agrarian and Natural Ecosystems of the European Part of Russia

Abstract

The results of the assessment of soil respiration (CO2 emission from soil) in three regions (Chuvash Republic, Ryazan and Kursk regions) are presented. Agrarian (crop and livestock) and natural ecosystems are combined into seven groups: croplands, pastures, hayfields, abandoned lands, forests, stockyards and open compost storages.CO2 emissions were measured in 2020–2022 using the close chamber method. Ecosystems were ranked by increasing rate of CO2 emission from soil in the following order: croplands (0.03–0.24 g C–CO2 m–2 h–1) pastures (0.07–0.33 g C–CO2 m–2 h–1) ≤ hayfields (0.06–0.35 g C–CO2 m–2 h–1) ≤ ≤ forests (0.07–0.28 g C–CO2 m–2 h–1) ≤ abandoned lands (0.08–0.37 g C–CO2 m–2 h–1) \( \ll \) stockyards (0.21–8.61 g C–CO2 m–2 h–1) \( \ll \) compost storages (1.15–13.85 g C–CO2 m–2 h–1). Estimates of CO2 emissions from pasture, hayfield, forest, and abandoned land soils were not statistically different in most cases. The dependence of soil respiration rate on hydrothermal (temperature and humidity of the upper soil layer, air temperature) and agrochemical (content of total carbon and total nitrogen in the upper soil layer, pH) indicators by geographical regions and by types of ecosystems was analyzed. The most important among the evaluated factors at both ecosystem and regional levels is soil temperature at the 10 cm depth (r = 0.41–0.88, p 0.05). Moisture conditions do not play a significant role in the formation of carbon flux. On the regional scale, the stocks of carbon and nitrogen are significant (r = 0.33–0.92, p 0.05), which are more dependent on the geographical location of sites than on the characteristics of economic activity. The considered indicators determine the variance of CO2 emission from soils of the studied ecosystems by 17–78%.