Maria Zumkeller, Nazareth Torres, Runze Yu, and Kaan Kurtural*
*University of California Davis, 1 Shields Avenue, Davis, CA 95616 (skkurtural@ucdavis.edu)

Anthropogenic climate change has left no viticulture region untouched. The San Joaquin Valley of California is the leading irrigated viticulture region in the world. There is little information on how best to preserve plant-available soil water before in-sea- son irrigation is initiated. We studied a grass (Poa bulbosa hybrid), barley (Hordeum spp.), and native vegetation as cover crops under till versus no-till system in a Ruby Cabernet/Freedom (Vitis spp.) vineyard. Our results indicated that grass under no-till preserved plant-available water, resulting in 30% greater midday stem water potential in grapevine. The net carbon assimilation of grass under no-till was also greater than barley and natural vegetation until cover crops went dormant or were terminated. There were no adverse effects of cover cropping or tillage in components of yield or primary or secondary metabolism of grapevine. Under the no-till system, net carbon assimilation of vineyard system was greatest with grass species. Our results will pro- vide a greater understanding of dynamics of the soil-grapevine-atmosphere continuum in the greater San Joaquin Valley under anthropogenic climate change.

Funding Support: University of California Davis Foundation