Soil temperature and moisture as a factor in the rate of carbon dioxide emission in crops of various agricultural crops and fallows

The objective of the study is to establish the influence of soil temperature and moisture on the dynamics of carbon dioxide emissions in crops of various agricultural crops and fallows. The study was conducted in 2023–2024 in crops of spring wheat, corn, alfalfa, black and occupied fallows. Carbon dioxide emissions were measured using a closed chamber method. The dynamics of soil temperature and moisture during the growing season depend on weather conditions, the type of crop grown, and fallows and vary in the range of 7.8–21.2 °C and 16.7–31.1 %. Carbon dioxide emissions in spring wheat crops vary in the range of 12.6–113.0 kg/ha per day, in alfalfa crops – 32.6–151.0 kg/ha per day, and in corn – in the range of 17.0–146.7 kg/ha per day. In black and seeded fallows, CO2 emissions are lower than in spring wheat crops by 34–62 % (14.6–51.2 kg/ha) and 22–55 % (15.7–44.9 kg/ha). A strong relationship was established between carbon dioxide emissions and soil temperature in spring wheat crops (r = 0.81), alfalfa (r = 0.81), corn (r = 0.91), black (r = 0.77), and seeded fallow (r = 0.77). Calculations revealed that a change in soil temperature by ±1 °C leads to a change in CO2 emissions per day according to the following scheme: black fallow (±3.4 kg/ha) < occupied fallow (±4.3 kg/ha) < spring wheat (±7.7 kg/ha) < corn (±10.2 kg/ha) < alfalfa (±10.5 kg/ha). A moderatestrength relationship was observed between soil moisture and CO2 emissions in spring wheat (r = 0.66), corn (r = 0.65), and alfalfa (r = 0.54) crops. A weak correlation was observed in fallow fields (r = 0.21–0.22). A ±1 % change in soil moisture leads to a daily change in emission intensity of ±2.4 kg/ha in spring wheat, ±2.7 kg/ha in alfalfa, and 3.7 kg/ha in corn.