Assessment of soil carbon dioxide emissions depending on the tillage system of ordinary chernozem in the Kostanay region

Abstract

Abstract
Background and Aim. Agricultural soils are a significant source of carbon dioxide (CO₂) emissions, the intensity of which is influenced by tillage practices, mineral nutrient availability, and soil biological activity. In Northern Kazakhstan, evaluating the effects of different agricultural technologies on the soil carbon balance has become increasingly important for mitigating greenhouse gas emissions and maintaining soil fertility. The aim of this study was to assess the dynamics of CO₂ emissions from
ordinary chernozem under different tillage systems and mineral fertilization regimes.
Materials and Methods. The study was conducted in 2025 at the Karabalyk Agricultural Experimental Station LLP in Kostanay Region, Kazakhstan. The experimental soil was an ordinary medium-depth heavy loam chernozem. Conventional tillage and No-till systems were evaluated under fertilized (N₃₀P₂₀) and unfertilized conditions, as well as on a fallow plot. Soil respiration intensity was measured
throughout the growing season of spring durum wheat using the Shtatnov method. Seasonal patterns of CO₂ emissions were analyzed, and correlations between soil properties and carbon dioxide fluxes were assessed.
Results. The results showed pronounced seasonal variability in CO₂ emissions, depending on tillage practice, crop growth stage, and mineral nutrition level. The highest rates of carbon dioxide release were recorded at the tillering stage of spring wheat, whereas a substantial decline was observed at maturity.
The highest emission values were associated with conventional tillage, whereas the no-till system reduced carbon losses throughout the growing season. In most cases, mineral fertilization contributed to lower CO₂ emission rates. Correlation analysis revealed only weak relationships between CO₂ emissions and both humus content and nitrate nitrogen concentration, indicating that hydrothermal conditions and soil biological activity play a dominant role in regulating carbon dioxide fluxes.
Conclusion. Soil tillage practice significantly affects CO₂ emissions from ordinary chernozem. The adoption of No-till technology contributes to reduced carbon losses and improves the stability of the carbon balance in agroecosystems. The highest carbon losses were observed on fallow soil during the spring period. These findings highlight the potential of conservation agriculture technologies as an effective approach to improving the environmental sustainability of agricultural landscapes in Northern Kazakhstan and reducing greenhouse gas emissions.