The aim of the study was to determine the parameters of a novel integrated stoichiometric model of the interrelated nitrogen and carbon cycles under conditions involving the implementation of different types of crop rotations, alternative types of organic fertilisation and varying methods of mechanical soil cultivation in the agrocenoses of the Forest-Steppe of Ukraine. The research methodology was based on a combination of long-term field observations and an integrated stoichiometric framework for evaluating nitrogen and carbon balances under different fertilization systems and soil tillage practices. It was established that the type of organic fertiliser directly correlates with the level of CO₂ emissions resulting from mineralisation processes: when manure is applied, the range of emissions is usually 25-85 tonnes, whereas the use of by-products increases this level to 80-160 tonnes. In the first scenario, a more intensive nitrogen removal relative to its input was observed, whereas in the second, a progressive increase in total stocks was recorded. An increase in CO₂ emissions in such cases is accompanied by an improvement in the soil carbon balance and an increase in the overall yield of the system. An assessment of the impact of black soil tillage methods showed that with non-inversion tillage technology - regardless of the type of crop rotation or fertiliser – a positive trend in soil carbon balance is observed, whereas with ploughing, the nature of the increase in organic matter deficit has a non-linear (parabolic) form. Ploughing is characterised by a wider range of CO₂ emissions, indicating more active mineralisation. The results of the study confirm the high efficiency of using shredded crop by-products in combination with appropriate nitrogen compensation via mineral fertilisers. The practical significance of the results lies in substantiating the effectiveness of using crop by-products and non-inversion tillage to stabilise nitrogen-carbon cycling, restore the fertility of chernozems and increase the productivity of agrocenoses in the Forest-Steppe of Ukraine.