Spatial Vineyard Variability on Soil, Grape Yield, and Juice Quality in a Field in the D.O.Ca. Rioja (Spain).
Ana Aizpurua, Olatz Unamunzaga, and Ander Castellón. NEIKER Instituto Vasco de Investigación y Desarrollo Agrario, C/ Berreaga, 1, Derio, Spain
Great spatial variability related to vineyard production is one of the main concerns for grapegrowers. Spatial variability can be observed both in grape yield and quality and it is caused by several factors related to climate, soil, vine (rootstock and cultivar) and viticultural techniques. The aim of this work was to study the variability associated to soil, grape yield and juice quality parameters. The work reported here was carried out during 2005 in a 8 ha field located in Oyón (Spain) where Tempranillo (red cultivar) is grown. Yield was measured and soil samples were taken at three depth increments (0-30, 30-60 and 60-90 cm) in 200 sampling points regularly distributed in the field. Soil depth, texture, pH, organic matter, total N, P, Na, K, Mg and carbonate contents were analized in all the samples. Aditionally, in 100 out of the 200 initially selected points the following juice quality parameters were measured: probable alcohol degree, total acidity, pH, malate, tartrate, K and anthocyanin concentrations. Grape yield showed the largest within-field variability, with coefficients of variation around 50%. Soil phosphorous content accounted for the highest variability in soil, while anthocyanin and malate concentrations were the most variable factors regarding quality of juice.