Shifting from Tillage to Cover Cropping in Warm Climate Viticulture: Seeking the Optimal Balance

Vineyard sustainability increasingly focuses on transitioning from traditional soil management practices, such as tillage and herbicides, to environmentally friendly methods like cover cropping and mulching. While this strategy works in cool climates with abundant rainfall, its application in warmer areas is not advisable due to potential disadvantages, such as water and nutrient competition from cover crops, which may outweigh the benefits. We examine the pros and cons of vineyard tillage, including data on evaporation rates from wet and dry tilled soils. We explore methodologies to quantify competition between vine roots and grass roots, focusing on distinguishing native versus spontaneous vegetation, duration and extent of cover cropping, species used in sown mixtures, and cover crop water use rates. Novel soil management practices are discussed as alternatives to traditional green manuring, such as mid-row rolling and sub-row sward mulching. The review updates recent approaches for establishing native or sown under-vine cover crops, which, with irrigation, might control native weeds while colonizing shallow soil, allowing grapevine roots to penetrate deeper, moistened soil layers. Promising grasses include creeping species such as Glechoma hederacea, Trifolium subterraneum, and Hieracium pilosella. Finally, we describe three soil management protocols: two suited to dry farm conditions and one involving blue water availability, which may mitigate cover crop competition for water and nutrients while maintaining benefits such as reduced soil erosion, increased soil organic matter, carbon sequestration, and improved machinery access.