Earth and Soil Sciences Department
BS in Soil Science
Dr. Thomas J. Rice
Zinfandel, also known as Zin, is a red skinned variety of wine grape very popular in California. The wines produced from Zinfandel grapes have an intense fruitiness and luscious texture. Production is extremely variable throughout California and is dependent upon, climate, soil fertility, crop level management practices, and irrigation. This study was conducted to determine the on site soil physical and chemical properties as a means to obtain optimal yields and fruit quality. The A & L Western Agriculture Laboratories performed comprehensive fertility analysis to determine the concentrations of the plant essential nutrients, organic matter, electrical conductivity, cation exchange capacity, and pH in the soils. This site has experienced considerable soil disturbance during the rainy seasons due to the erosion of the Salinas River bank bordering the eastern side of the site as well as the non-vegetative ground to the north. Unfortunately, bare soil is highly susceptible to erosive losses. Valuable topsoil can be lost and areas can be deeply cut by gully erosion during the rainy season. The best erosion treatment is to take prevention measures. Therefore, it is recommended that any areas with bare soil be vegetated before next winter’s rainy season. Irrigation rates should be adjusted throughout the year in accordance with annual precipitation, average wind speeds, average temperature, and the evapotranspiration rate. Special considerations should be made where irrigation water could run off a steep slope. On these sites vegetation must be established, and measures taken to offset sediment loss due to erosion. Zinfandel vines appear to be sensitive to a variation in soil classifications and the effect of the loss of topsoil. With an improvement in land use management this specific site shows considerable potential to be a long term winemaking site.