2012 Annual Report 1a.Objectives (from AD-416): 1. Develop sustainable disease control practices for grapevines. [NP 303, C3, PS3B] 2. Develop sustainable vineyard floor management practices for vineyards. [NP 305, C1, PS1B.1] 3. Develop sustainable water management practices for vineyards. [NP 305, C1, PS1B.1] 4. Investigate the impacts of vineyard practices on soil microbial ecology. [NP 305, C1, PS1B.1] 1b.Approach (from AD-416): 1. Characterize the infection process of grapevine roots by the fungal pathogen Armillaria mellea, the causal agent of Armillaria root disease; Characterize the significance of riparian areas in the spread of Pierce's disease. 2. Identify differences in regional populations of Conyza canadensis, cover crops that effectively compete with C. canadensis, and the effects of soil resource availability on competition between cover crops and C. canadensis; Identify cover crops that effectively compete wtih problematic weeds. 3. Evaluate the interactive effects of irrigation practices and vineyard floor management practices on grapevine yield, growth, physiology, and nutrition. 4. Examine the effect of cover crop functional type on soil microbial communities and microbially-mediated soil processes; Characterize rhizosphere communities associated with Vitis rootstocks; Examine the impacts of vineyard floor practices on mycorrhizae. REPLACING 5306-21220-004-00D (03/12); 5306-21220-003-00D (01/07) 3.Progress Report: This new project was implemented on 03/01/2012 and replaces former project 5306-21220-004-00D. In FY2012, research on sustainable viticulture addressed significant gaps in the scientific knowledge, which in turn facilitated the development of effective, sustainable methods of disease control, vineyard floor management, land-use management, and irrigation for US grape growers. First, we tracked the carbon storage capacity of mature grapevines and adjacent wild habitats, which are the first of such empirical measurements of commercial vineyards. These are critical for the development of national and international environmental policies, which will establish carbon contributions and offsets for many different sectors of the US economy. Second, we developed new technologies for accurate and user-friendly measurement of water use in vineyards. Water use is and will forever be an important priority for US grape growers, particularly in the arid western states, where grape production is dependent on irrigation. Third, we characterized susceptibility of different grapevine cultivars to a comprehensive set of trunk diseases. This work included not only California wine grapes, which have been the focus of past research, but also cultivars of table grapes grown in California, and juice grapes grown in Washington and New York. With a focus on grape production across the US, which includes cultivars adapted to different climates and different production systems, we can now evaluate the risk of trunk disease across a broader sector of the US grape industry. This helps us target control practices to prevent certain trunk diseases on the most susceptible cultivars. Review Publications Shapland, T.M., Mcelrone, A.J., Snyder, R.L., Paw U, K. 2012. Structure function analysis of two-scale Scalar Ramps. Part I: Theory and Modeling. Boundary Layer Meteorology. DOI: 10.1007/s10546-012-9742-5. Shapland, T.M., Mcelrone, A.J., Snyder, R.L., Paw U, K. 2012. Structure function analysis of two-scale Scalar Ramps. Part II: Coherent structure scaling and surface renewal applications. Boundary Layer Meteorology. DOI: 10.1007/s10546-012-9740-7.