In California, most precipitation occurs in the winter, and in the North Coast region, vineyard managers frequently plant cover crops or allow naturalized vegetation to grow in vine middles (strips between vine rows) during winter months. Vineyard managers choose these plant cover systems based on many factors including cost, convenience, and the potential for competition with vines for water and soil nutrients. These systems also have the potential to change soil health, impacting the soil’s organic matter content, structure, nutrient cycling, water infiltration and storage, and erosion potential. In Boonville, in California’s North Coast vineyard region, a replicated field demonstration compared commonly used plant cover systems (PCS) that differ in tillage requirements and plant cover.
Soil health tests with the greatest sensitivity to plant cover systems after five years were:
- water stable aggregates, showing a trend toward greater water stable aggregates in no-till than tilled plant cover systems, and
- mineralizable carbon, 96 hour rate, with higher rates in tilled than no-till plant cover systems.
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