WEED-CONTROL INFLUENCES VINEYARD MINIMUM TEMPERATURES

In a field experiment, post-emergence herbicides, disking, and mowing were used to control weeds between the vine rows in four vineyards, in the Napa and Sonoma Valleys evaluated over a three year period. Herbi cide treated vineyards had minimum temperatures 0.3 degrees C to 0.6 d egrees C higher than disked or mowed vineyards on most nights during t he spring freeze season. Mowed vineyards had minimum temperatures abou t the same as the disked vineyards on most nights. Vine canopy develop ment did not seem to influence treatment differences, but treatment ef fects on minimum temperature were greater on colder nights.