Optimal Viticultural Systems Comparison
The 1995 season represents the initial year of data collection for this project. Viticulture production system treatments continue to be established. Treatments included in the study are conventional, biologically intensive, and organic production systems. Production systems are being evaluated for effects on soil microbiology, viticultural and enological performance, populations of destructive and beneficial arthropods, and economic performance. Experimental protocols for sampling and analysis of soil microbiology in the study were developed during 1995. Soil samples collected in August and in October 1995 were analyzed for physical properties (water content, dry mass, and water holding capacity) as well as for chemical parameters (pH and total nitrogen). In the realm of microbiology, samples were analyzed for soil dehydrogenase activity, actinomycete enumeration, and microbial biomass. In addition, soil samples from all treatment plots were analyzed for plant parasitic nematodes. Soil microbiological analysis suggested high activity in the conventional treatment, intermediate activity in the conventional treatment, and low activity in the biologically intensive plots. It should be noted that this data is the result of the first season of data collection and is only preliminary. Plant parasitic nematode populations were quite low and did not appear to be influenced by production system. Nutritional status of vines was adequate and was not influenced by production system. Initial yield, fruit composition, wine quality and dormant pruning weight data will be collected during the 1997 season. Population patterns of important arthropods were monitored at approximately two week intervals from June through October. Population densities were low due to the fairly sparse canopy in the young vineyard. However, the following beneficial insect predators were detected; lady beetles (Coleoptera: Coccinellidae), green lacewings (Neuroptera: Chrysopidae), minute pirate bugs (Hemiptera. Anthocoridae), rove beetles (Coleoptera: Staphylinidae), and hover flies (Diptera: Syrphidae). These data are preliminary and continued development of the vineyard will enhance our ability to detect treatment differences.