2010 Annual Report 1a.Objectives (from AD-416) 1. Determine the impact of maintaining cover crops in vineyard alleyways on vine growth and development. 2. Determine the extent of biomass generation of cover crops and nutritional contribution to young vines. 3. Evaluate weed biomass and emergence in vine rows and in alleyways. 4. Evaluate the effects of alleyway cover crop management on soil moisture, rooting patterns of young vines. 1b.Approach (from AD-416) Pruning weights will be measured at the beginning of the study to establish a baseline of the vine size prior to the treatment season and at the end of each year of the study to determine vine size and vegetative growth of the vines in response to treatments. Mowing of cover crop will be performed up to two times in a growing season with the first mowing taking place in spring. Treatments will be mowed when the cover crop stand reaches a pre-determined level of biomass appropriate to mulching. Density of cover crop stands will be observed with a random sample taken with a quarter meter square quadrant placed randomly into the treatment. Weed biomass between rows will be evaluated in tandem with cover crop biomass, by manually separating weed and cover crop biomass within the quarter meter square quadrant samples, taken just before mowing. Soil moisture within the vine row and alleyway will be monitored bi-weekly from mid-June through September using gravimetric soil moisture determination (w/w), with early season measurements in May. Measures from June-September will be concurrent with measurement of vine water use efficiency. 3.Progress Report After the preliminary research year (2009) we were able to summarize vine growth differences with the different management treatments in commercial vines and the interplanted vines. Shoot length was measured across three dates in 2009, and MS3 was found to have longer shoot growth than the unplanted (UN) treatments across the season . At this point in the 2010 season, there are no differences in shoot length when comparing treatments. Total vine leaf areas in 2009 were found to differ by mulch treatments as MS1 and MS3 had greater total vine leaf area than other treatments at véraison; no differences were found with treatment at bloom, perhaps due to more even soil moisture and lack of time post-treatment imposition to have an effect on vine growth. It should be noted here that the leaf areas were due to larger leaf area/shoot as there was no difference in shoot number per vine. Leaf areas are being collected this season and will be reported during the next reporting cycle. Methods of ADODR monitoring included stakeholder meetings, teleconferences, and e-mail.