Influence of soil characteristics on vine growth, plant nutrient levels and juice properties: a multi-year analysis

Soil physical and chemical properties affect vine nutrition, as indicated by leaf and petiole nutrient content, in a way that may directly impact wine properties. The goal of this multi-year project is to study the relationship between vineyard soils and the wines produced on them using a variety of biogeochemical and mineral analyses, coupled with an analysis of vine properties and juice characteristics. This study examines leaf and petiole nutrient levels, as well as fruit and juice characteristics, of own-rooted Cabernet Sauvignon vines grown on four distinct soil types in the same Paso Robles vineyard. The soils were classified as Palexeralfs, Haploxeralfs, Haploxerolls and Haploxererts. The four soils exhibited important morphological differences in color, coarse fragment content, texture, water holding capacity, and hydraulic conductivity. The soils also showed important differences in chemical characteristics and nutrient availability. The soils covered contiguous vineyard patches planted with the same cultivar, on its own roots. The vineyard was irrigated and fertilized. Mesoclimatic conditions and slope aspect were similar. Soils were analyzed for physical and chemical differences to determine the influence of the four contrasting soil types on differences in vine growth, water stress and plant nutrient levels. Differences in cation exchange capacity and cationic balance in the soil solution appeared to affect nutrient availability to the vines, and likely contributed to the observed differences in the plant and fruit characteristics. Berries harvested on the four blocks exhibited different sensory attributes, as determined by a tasting panel. In an analysis of data from three consecutive growing seasons, many of the observed differences in plant vigor between vineyard blocks were consistent from year to year, as were differences in fruit yield and juice properties. Taken together, these findings support a role for soil texture, water and nutrient availability on vine and fruit parameters, and emphasize that differences in soil properties within a single vineyard may require site-specific management practices.