Abstract
Background and Aim. Organic carbon dynamics and carbon dioxide (CO2) emissions of soil are important indicators of soil functioning and the sustainability of agricultural systems. In Northern Kazakhstan, intensive soil cultivation and contrasting climatic conditions may influence themineralization of soil organic matter and soil nutrient availability. Conservation tillage practices, including no-till, may contribute to maintaining carbon in soil and soil fertility; however, their effects on CO2 emissions and agrochemical properties of ordinary chernozem under regional conditions remain studied insufficiently. To evaluate the effects of soil tillage systems and mineral fertilization on the intensity of carbon dioxide (CO2) emissions and agrochemical properties of ordinary chernozem under the conditions of Northern Kazakhstan.Materials and Methods. Field experiments were conducted during 2024–2025 at the Karabalyk Agricultural Experimental Station on ordinary chernozem soil. Conventional tillage and no-till systems, as well as fallow treatment, were analyzed under unfertilized (control) and mineral fertilizer (N30P20) conditions. The intensity of CO2 emissions of the soil was determined at the main growth stages of spring wheat. Humus content, nitrate nitrogen (N-NO3), available phosphorus (P2O5), and exchangeablepotassium (K2O) were also determined.Results. The intensity of soil CO2 emissions depended on the tillage system and mineral fertilization. The highest CO2 emission was recorded at the tillering stage, reaching 25.0 g CO2 /m-2 under conventional tillage with the use of mineral fertilizer. By the end of the growing season, CO2 emissions decreased to 2.1-4.1 g CO2/m-2. Higher temperatures in 2025 enhanced organic matter mineralization and stimulated carbon cycling. Compared to conventional tillage, the no-till system maintained morestable humus content and mineral nutrient levels.Conclusion. The no-till system combined with mineral fertilization contributes to the preservation of soil fertility and the stabilization of the soil carbon regime, thereby improving the efficiency of sustainable farming systems under the Northern Kazakhstan conditions.