Monoculture and winter cover crop mixtures and their decomposition in a subtropical environment

The use of cover crops during the winter period is the foundation of the no-till system and provides physical, chemical, and biological benefits to the soil. A high biomass input from cover crops and benefits related to nutrient cycling also enhance the presence of beneficial soil microorganisms. Thus, this study aimed to evaluate dry matter phytomass production, the soil coverage curve with cover crops, and the decomposition curve of dry matter phytomass in monoculture and cover crop mixtures in a subtropical environment. The following cover crop treatments were evaluated during the winters of 2022 and 2023 using a randomized block experimental design: black oat, rye, common vetch, forage radish, black oat + common vetch, black oat + forage radish, black oat + common vetch + forage radish, rye + common vetch, rye + forage radish, and rye + common vetch + forage radish. Dry matter phytomass production, soil coverage, and dry matter phytomass decomposition were measured using the litter bag method. Black oat and forage radish in monoculture stood out for their dry matter phytomass production, and forage radish excelled in mixed treatments, presenting values exceeding 50% of the composition in all cases. Soil coverage was adequate for black oat, rye, common vetch, and forage radish in monoculture and their intercropping systems. After 150 days of decomposition, black oat and rye exhibited the lowest decomposition rates, and the cover crop mixtures showed intermediate decomposition rates, confirming their suitability as autumn/winter cover crops in subtropical environments.