Self-reseeding annual legumes evaluated as cover crops for untilled vineyards

Self-reseeding annual cover crops can regenerate in subsequent years without tilling the seedbed and can be part of a strategy to protect vineyard soil from erosion. We compared 22 such cultivars in a 1-year-old ‘Syrah’ wine-grape vineyard located at 1,400 feet in Lake County. We found significant differences between species in the amount of biomass produced in 2004 and 2005. All of the species studied were relatively low statured and fit well in vineyard middles. Pressure bomb readings taken after the cover crops stopped growing showed that with a dry spring (2004), vines with cover crops were modestly more stressed than those under tillage prior to July irrigations, but after irrigation the cover-cropped vines were slightly less stressed. In 2005, which had rainfall in late spring, there were no differences in vine water status throughout the season. We conclude that water use by the cover crop must have been relatively low and did not result in excessive vine water stress.