- Summer 1997 "Update" Newsletter Article -
Long-term study to compare viticultural methods
From CATI Publication #970701
Copyright © 1997. All rights reserved.
A multi-year study comparing conventional, biologically intensive and organic methods of grape production in the same vineyard is under way under the guidance of two plant science specialists at California State University, Fresno.
The study is one of the first of its kind and will employ the three distinct viticultural practices in a Merlot vineyard in Mendocino, California, note project directors Keith Striegler, a research scientist and the new director of Fresno State¹s Viticulture and Enology Research Center (VERC), and Mark Mayse, professor of entomology in the Department of Plant Science.
This study is unique in its multi-faceted approach viticultural research, tracking everything from soil conditions and vine nutritional status to cost of production and value of returns.
"The overall goal of this research is to comparatively evaluate over several years the relative strengths and limitations of three distinct and dynamic systems of viticultural production and protection," Mayse writes in a project report recently published by the California Agricultural Technology Institute (CATI). "Relatively few research projects as comprehensive in scope have been conducted in perennial cropping systems," he said.
Data collection for the project will center in the following four key research areas:
- Identifying and monitoring microbiological and nutrient features in the root zone of the plants;
- Evaluating viticultural and enological features such as vine nutritional status, dormant season pruning weights, and fruit and wine composition;
- Monitoring population patterns of destructive pests such as western and variegated grape leafhopper nymphs and western grape leaf skeletonizer, and tracking densities of beneficial arthropods such as spiders;
- Comparing economic aspects such as cover crop maintenance, pest control management, and production returns.
The viticulture methods used in the conventional production treatment will be to keep row middles clean of vegetation during summer growing season; to use synthetic fertilizers at typical recommended rates on a calendar basis; and to use registered pesticides according to label rates for prevention and treatment of problems.
Key methods in the biologically-intensive treatment will include planting cover crops in row middles and keeping them mowed during growing season; restricting nitrogen intake to that which is gained naturally from the cover crops; and using primarily "soft" pesticides on an as-needed basis for pest control.
Methods of organic treatment will include cover crops; compost to provide nitrogen; foliar feeds to supply other nutrients; and "organically-allowed" pesticides.
Irrigation will be according to standardized drip application methods.
In addition to the Mendocino County site, another series of trials with two of the three treatments is under way on the Fresno State campus. Treatments of organic and conventional practices are being monitored in a Barbera vineyard on the university farm.
Title of the report outlining this project is "Optimal Viticulture Systems Comparison." Copies are available and may be viewed or requested from the Research Publications page. VERC's new World Wide Web site is at http://cati.csufresno.edu/verc.{ page top }