Key points are not available for this paper at this time.
Conservation Agriculture for vegetable production, which is designated as No-Tillage Vegetable System (NTVS) in southern Brazil, sustainably improves food production through the strategic arrangement of cover crops (CCs) in crop rotation. However, the functional differentiation of CCs arrangements needs further understanding in NTVS. This study investigated the functional differentiation of CCs combinations in an NTVS in southern Brazil. The experiment was conducted on a Humic Dystrudept soil in southern Brazil. Treatments included: T1 — fallow in fall/winter (weeds, mainly Galinsoga parviflora ) followed by onion ( Allium cepa L.) and then corn ( Zea mays ) (F/Oni/C); T2 — turnip forage ( Raphanus sativus L.) in fall/winter followed by onion and then millet ( Pennisetum glaucum ) (T/Oni/M); T3 — mix of oats ( Avena strigosa ) and turnip forage in fall/winter, followed by onion and then beans ( Phaseolus vulgaris ) (O+T/Oni/B); and T4 — oats in fall/winter followed by onion and then soybean ( Glycine max ) (O/Oni/S). From 2024–2025, after 16 years of long-term experiment that has been carrying out, the following traits were evaluated: soil penetration resistance (PR) (0–50 cm); aggregate stability (0–10 cm); water infiltration into the soil (using concentric double ring); carbon (C) and nitrogen (N) contents (0–10 cm); β-glucosidase enzyme activity and glomalin fractions (0–10 cm); qualitative indices of soil structure and health; and biomass production by CCs. The onion yield data from 2019 to 2024 was also added to the database. The system with the greatest diversity of CCs (O+T/Oni/B) showed the highest water infiltration. The T/Oni/M treatment promoted greater enzymatic activity and lower PR (0–15 cm). Treatments with summer grasses (T/Oni/M; F/Oni/C) resulted in higher biomass production and improved qualitative indexes of soil health, while those with summer legumes (O+T/Oni/B; O/Oni/S) increased onion yield. Aggregate stability, C and N content, and glomalin levels in the soil were high across treatments but had no significant differences. In conclusion, each CC system provides specific benefits to the soil. These findings demonstrate the high degree of functional differentiation of CCs in organic NTVS, allowing management to be tailored to goals (e.g., biomass production, biological activity, water infiltration, or crop yield). The diversity of species, the quantity and type of biomass, and seasonality influence the physical and biological properties of the soil and the functional differentiation between CCs in a long-term organic NTVS. Qualitative indicators of soil health complement quantitative indicators and broaden the functional differentiation of CC arrangements, guiding the regenerative management of soil health.
Rauber et al. (Thu,) studied this question.