Issue link: http://winesandvines.uberflip.com/i/498427
84 P R A C T I C A L W I N E R Y & V I N E YA R D May 2015 84 P R A C T I C A L W I N E R Y & V I N E YA R D May 2015 G R A P E G R O W I N G Thus, nearly all sulfur applied to the vineyard each year was exported in solu- tion waters. Our study focused on collecting detailed measurements in only two vineyards within Napa Valley. Across the region, differences in management practices, vineyard soil properties and rainfall may affect the degree to which applied sulfur is retained in local soils, or transported off-site. However, we believe that the general patterns in our results can be applied across northern California winegrowing regions due to three main factors: 1) Elemental sulfur is the fungicide of choice by many winegrowers, 2) There are few mechanisms by which applied sulfur can be retained within vineyards (in soils or vegetation bio- mass), and 3) The entire region is subject to dry grow- ing seasons followed by wet dormant seasons (the Mediterranean climate). We expect that these factors — relating to sulfur inputs, retention potential and transport potential — lead to the majority of applied sulfur being exported from vineyards each year. The important question is whether or not sulfur exported from vineyards has unintended consequences in the water- shed. This is a sensitive topic with wine- growers, due to the efficacy of sulfur as a fungicide and the concern that its use will be banned. Our study points to the need for greater attention to understanding the ultimate fate of sulfur exported from vineyards and other agricultural systems where its use is prevalent. Although the impacts of sulfur applica- tions may be minimal within vineyards currently, transport to aquatic ecosys- tems with fluctuating oxygen conditions could be environmentally problematic. There, sulfate can affect the mobiliza- tion of mercury and other heavy metals, which are toxic to fish and wildlife. Promoting an environmentally sus- tainable industry relies on investigating this topic, given past lessons from eco- system studies of sulfur deposition in acid rain. Based on this study, further research should explore the patterns of sulfur transport from vineyards to aquatic sys- tems, evaluate the cycling of sulfur within aquatic systems, and investigate fungicidal alternatives (and their envi- ronmental consequences) for powdery mildew control. PWV Acknowledgments Eve-Lyn Hinckley was supported by an Environmental Protection Agency Science to Achieve Results Fellowship, the Geological Society of America and Stanford University funds. Thanks to the vineyard managers in Napa Valley who granted access to their vineyards for this research. A technical ver- sion of this study originally appeared in Proceedings of the National Academy of Sciences. 10 Bibliography 1. Aulakh, M.S. and I.M. Chhibba. 1992 "Sulfur in soils and responses of crops to its applica- tion in Punjab." Fertilizer News 37: 33–45. 2. Aulakh, M.S. and N.S. Pasricha. 1986 "Role of sulphur in the production of the grain legumes." Fertilizer News 31: 31–35. 3. California Dept. of Pesticide Regulation (CDPR) [Available online: calpip.cdpr.ca.gov/cfdocs/ calpip/prod/main.cfm]. 4. Charles, D.F. and S. Christie. 1991 Acidic Deposition and Aquatic Ecosystems: Regional Case Studies (Springer-Verlag), 747 pp. 5. Cronan, C.S. and C.L. Schofield. 1990 "Relationships between aqueous aluminum and acidic deposition in forested watersheds of North America and northern Europe." Environmental Science & Tech. 24: 1100– 1105. SUPPORT RESEARCH & WINE INDUSTRY NEEDS THROUGH THE A M E R I C A N V I N E YA R D FO U N D AT I O N P.O. Box 5779, Napa, CA, 94581 • T: (707) 252-6911 Visit our Web site at www.avf.org for information on funding and current research projects OX I DAT I O N O F W I N E Dr. Andrew Waterhouse is studying sulfur dioxide and glutathione, the key compounds available to winemakers for management of wine flavor evolution that naturally occurs during aging. His recent work has shown that oxidation outcomes are very different when sulfur dioxide levels drop to zero and that glutathione can protect against some oxidation reactions, but allows more color development than sulfur dioxide. For more information visit AVF.org or contact Dr. Waterhouse at alwaterhouse@ucdavis.edu For a wealth of useful viticulture and enology research and information, visit AVF.org, ngr.ucdavis.edu, asev.org, iv.ucdavis.edu or ngwi.org Finding Solutions Through Research