Residual Dry Matter, Weeds and Soil Aggregates after Winter Cover Crop

Soil quality maintenance in a no-tillage system (NTS) depends on cover crops. They are essential for crop rotation, affect several soil attributes, and contribute to phytosanitary control. However, cover crop efficacy is influenced by their root function and the presence of plant straw on soil surfaces. The objective of this study was to compare various winter cover crops in terms of their effects on dry mass yield, straw persistence after 40 d, weed incidence, and soil aggregate stability. The soil tested was an Oxisol Ustox Hapludox in Western Paraná State, southern Brazil. A randomized block design was used with four replicates and six treatments (fallow, black oat, fodder turnip, field pea, common vetch, and fodder turnip + black oat). Cover crops were managed 88 d after sowing. Dry mass (DM) and residual dry mass (RDM) were measured at 20 d and 40 d after harvest. Aggregate stability and weed type and density were evaluated after 40 d of management (DAM). The results showed that black oat obtained the lowest decomposition; therefore, a potential species to be used in the system of crop rotation in the no-tillage. The consorted of fodder turnip and black oat provided relatively higher dry mass yields and improved soil aggregation. Cover crops reduced the incidence of weeds, being important for no-till sustainability.