Alleyway Cover Crops Have Little Influence on 'Pinot noir' Performance

Competition between ‘Pinot noir’ grapevines and alleyway cover crops\ud was evaluated in two commercial vineyards in western Oregon. Seven\ud cover crop treatments including a clean-cultivated control were applied\ud in the fall of 2003 and their impact on vines was monitored in 2004\ud and 2005. Competition with grapevines was assessed by measuring\ud soil moisture, vine growth, vine water status, vine nutrient status, yield,\ud and must quality over two years with typical weather patterns for the\ud region. Despite large treatment differences in cover crop biomass and\ud N contributions to the soil from mowed residues, cover crops had little\ud measurable influence on vine growth or fruit quality. Small differences\ud in alleyway soil water content, leaf nitrogen, and juice YANC were\ud found between different treatments; however, no cover-cropped\ud treatment differed from the clean-cultivated control. Alleyway cover\ud crops managed by spring and summer mowing do not appear to\ud compete significantly with established ‘Pinot noir’ grapevines in\ud western Oregon vineyards. Therefore, advantages of using cover\ud crops (e.g. protection against soil erosion and addition to soil organic\ud matter) can be realized without impacting vine productivity or juice\ud quality. The long term impact of certain cover crops, including the\ud clover mix we used, could result in the supply of too much N to vines\ud and this aspect should be further examined