Cover cropping associated with no-tillage system promotes soil carbon sequestration and increases crop yield in Southern Brazil

Tillage and cover crops influence soil carbon stocks and nutrient cycling by altering mineralization and nutrient input rates. This study aimed to assess the effects of different tillage systems and winter cover crops on soil carbon stock and maize yield in Southern Brazil. Three tillage treatments were compared: conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The winter cover crops were: common vetch ( Vicia sativa L.), fodder radish ( Raphanus sativus L.), and black oat ( Avena strigosa L.). Soil sampling was performed 4.5 years after the beginning of the experiment. Samples were taken through the excavation method (0 - 45 cm depth) and evaluated for organic carbon content and bulk density. NT plots had the highest carbon stock (80.22 +/- 0.77 Mg ha - 1 ), regardless of the cover crop. The lowest carbon stock (61.09 +/- 0.69 Mg ha - 1 ) was recorded on CT soil under common vetch. Vetch increased maize yield in CT and RT treatments by 10 - 38% and 26 - 34%, respectively, but its lower dry matter production and C input led to reduced soil carbon stocks compared with fodder radish and black oat. Our results confirm that soil conservation practices such as NT combined with the use of high input and quality cover crops promote environmental and agronomic benefits, increasing soil carbon stock and maize yield.