Potential of no-till agriculture as a nature-based solution for climate-change mitigation in Brazil

Despite increasing efforts to combat climate change, greenhouse gas (GHG) emissions continued to grow. In this context, conservationist agricultural systems such as no-till (NT) can play an important role. However, the po-tential of this system to mitigate GHG emissions has been questioned more recently. Brazil is the second country with the largest NT area, representing around 18% of the global area under NT. Here, we examined the effects of the adoption of NT from the conversion of native vegetation, conventional tillage (CT), and pasture in layers 0-30 and 0-50 cm of the soil. We used a total of 124 comparison pairs to analyze changes in soil organic carbon (SOC) using two approaches (deriving SOC change factors and the adjustment of empirical equations on SOC temporal dynamics). Our results showed that the adoption of NT in NV areas reduces SOC stocks by between 4% and 8%. However, in areas previously managed by CT systems or pasture, NT is a potential alternative for promoting carbon sequestration in agricultural soils in Brazil's different regions. The results showed that the SOC accumulation is not restricted to superficial layers of the soil (0-30 cm) but was also effective up to 50 cm in depth, with gains varying between 9% and 25%. Thus, our results consistently demonstrate that for Brazilian conditions, NT when compared to CT systems or pastures, predominantly result in SOC gains, and represent an alternative to promote sustainable agriculture, which can contribute to the mitigation of GHG emissions and food security.