Mixture of winter cover crops reduces surface runoff and sediment production under no‐tillage system for Oxisols

Abstract

AbstractOne of Brazil's efficient soil and water conservation practices is the no‐tillage system (NTS). Nonetheless, erosion during rainfall still causes soil and water losses in this system. Therefore, this study aimed to assess surface runoff in different cultivation systems and sediment production during rainfall events. In macro‐plot 1 (non‐terraced catchment [NTC]), we adopted the NTS management with up‐ and down‐slope farming without including mechanical runoff control practices, which most regional producers use. In macro‐plot 2 (best management practices [BMPs]), we optimized crop rotation by incorporating a mixture of cover crop species in autumn and implemented contour farming practices. In macroplot 3 (terraced catchment [TC]), we adopted the same soil management practices as the NTC macroplot, including mechanical runoff control using broad‐based terraces. We used rainfall data to create hyetographs, hydrographs, and sedimentographs, aiming to evaluate the impact of management practices on surface runoff and sediment production. The surface runoff was reduced by 81% (BMPs) and 88% (TC) compared to the NTC system. There was also a reduction in suspended sediment concentration, around 33% (BMPs) and 63% (TC), compared to the NTC system. Despite conservation systems have shown effectiveness in reducing surface runoff and sediment production, monitoring these systems during periods not influenced by the La Niña phenomenon is necessary to assess the impact of rainfall events on soils with conservation practices in extreme events. The study findings provide guidance and recommendations for agricultural producers and field technicians globally, offering criteria for selecting optimal soil and water management practices in no‐till systems. This promotes a conservation‐oriented approach to agriculture.