Carbon Dioxide Emission Dynamics in Corn Crops When Applying Various Doses of Organic Fertilizers

The objective of the study is to determine the effect of applied organic fertilizers on changes in the intensity of carbon dioxide emissions from the soil surface under corn crops. The studies were conducted in 2024–2025 on leached chernozem. The experimental design included variants with organic fertilizer application at rates of 30, 60, and 90 t/ha. A variant with natural soil fertility was used as a control. Organic fertilizers were applied in the fall with a ROU-6 spreader before the main moldboard tillage to a depth of 20–22 cm. Fertilizers were not applied under the control variant. In the spring, harrowing was carried out in two passes, followed by cultivation to a depth of 8–10 cm and sowing of corn with a precision seeder. After this, the soil was rolled with ring-spur rollers. The seeding rate was 80,000 seeds per hectare. During the warm season (May–October), carbon dioxide emissions were measured every 10–16 days. Carbon dioxide emissions during the corn growing season from May to July increased in the control group from 36.2–50.5 to 183.0–197.2 kg CO2/ha per day and then decreased by mid-autumn to 6.5–8.3 kg CO2/ha per day. In the fertilized variants, the dynamics of soil respiration had a similar trend, but was higher by 21–149 kg CO2/ha per day from May to September. In an excessively wet year with an HTC of 1.4 units, the rate of CO2 production in the studied variants was higher in June by 31.1–90.4 kg/ha, and lower by 21.2–48.2 kg/ha in August and September compared to the period with an HTC of 1.2 units. The coefficient of seasonal variation in carbon dioxide emissions during the growing season ranged from 56.4 to 62.0% and remained virtually constant over the years of study.