Long-Term Cropping System Diversification Under no-Till Improves Soil Structure, Carbon Stocks, and Crop Yield in Tropical Environments

Conservation agriculture (CA) is a promising strategy for restoring soil quality, increasing crop production, and mitigating climate change. However, information on the effects of long-term no-till and cropping system diversification on soil quality, carbon dynamics, and crop productivity in tropical environments remains limited. This study evaluated the effects of ten years of diversified cropping systems under no-till management on a very clayey Oxisol in the Brazilian Cerrado. Ten production systems were evaluated, including maize monoculture, maize intercropped with Piatã grass, soybean monoculture, crop rotations involving pasture phases, and native Cerrado vegetation as a reference condition. Soil physical and chemical properties, soil carbon stocks, soil quality indicators, and crop productivity were assessed after ten years of management. Cropping system diversification improved soil physical quality and carbon dynamics compared with simplified systems. Maize intercropped with Piatã grass showed higher productivity and improved soil structural conditions than maize monoculture. Systems integrating pasture phases increased soil carbon stocks and promoted greater structural resilience. The maize–Piatã intercropping system and the rotation including two years of pasture followed by maize maintained soil carbon levels similar to those observed under native Cerrado in the surface layer. In contrast, soybean monoculture showed poorer soil physical quality indicators and lower carbon retention capacity. The combination of no-till, crop diversification, and forage grass integration enhanced soil functioning by improving structural quality and promoting carbon accumulation in a very clayey tropical Oxisol. These results confirm that diversified crop–pasture systems represent an effective strategy for mitigating soil degradation and sustaining agricultural productivity in the Brazilian Cerrado.