Introduction 

    The application of fertilizers is a common practice in agricultural production, with nitrogen fertilizers being particularly significant (Grados et al., 2022). Nitrogen fertilizers not only supply essential nutrients to crops but also enhance soil quality, leading to healthier soils and increased crop productivity (Zhang et al., 2024). However, nitrogen transformations in soil are highly dynamic. Ammonium nitrogen (NH4+-N) can undergo nitrification and denitrification processes, converting into nitrous oxide (N2O) and nitric oxide (NO), which are subsequently released into the atmosphere, contributing to environmental pollution (Das et al., 2023). Conventional nitrogen fertilizers, such as urea, have been shown to exacerbate these environmental issues (Oertel et al., 2016). Therefore, there is a pressing need to develop eco-friendly and cost-effective fertilizers that can improve crop yield and biomass while mitigating environmental impacts.

        Sulvais's Carbon Control Technology (CCT™) is a patented, simple, scalable, and cost-effective process for sequestering atmospheric CO₂ while delivering multiple agronomic and environmental benefits. One of its innovations, CCT-ammonium sulfate (CCT-AS), is a newly developed high-value, carbon-based enhanced efficiency fertilizer created using CCT™ technology. By blending CCT-AS with different materials, new fertilizers have been developed, such as CCT-BL (CCT-AS with low-carbon-content biochar), CCT-BH (CCT-AS with high-carbon-content biochar), and CCT-W (CCT-AS with wood biochar). These fertilizers have a carbon content of 10–30%, nitrogen content of 9–11%, and sulfur content of 11–13%. This unique composition allows these products to deliver multiple nutrients to the soil, making them capable of providing various benefits such as increasing crop yields, improving soil quality, sequestering carbon, and reducing soil greenhouse gas emissions. However, the effects of these new fertilizers on crop yield and soil nutrient availability compared to traditional fertilizers (e.g., ammonium sulfate (AMS), urea) and high-carbon-content amendments (e.g., biochar and humic acid) and their combinations remain unclear. Further research is required to collect data and deepen our understanding of these impacts.