Relationships between Soil Characteristics and Brewing Grape Quality in Katsunuma, Yamanashi Prefecture, Japan

Abstract

In this study, the qualities of Chardonnay grapes from Katsunuma, Yamanashi Prefecture used for making wine, in, and the physical and chemical properties of the soils around the target fruit trees were analyzed to define the relationships between the grapes and soil properties. The survey covered three garden sites from one winery in Katsunuma Town. Undisturbed soil and disturbed soils were sampled from a depth of 20 cm, 30 cm below the trunk of the vines, and were used to measure physical and chemical properties, respectively. The physical properties measured were three-phase distribution, soil particle size composition, and hydraulic conductivity. Chemical properties measured were pH, EC, K₂O, Na₂O, CaO, and NO₃-N. Grapes were collected at harvest time, de-stemmed and pressed, and then analyzed for sugar content, glucose, fructose, acidity, malic acid, and tartaric acid. Software R was used for statistical analysis. The experimental results indicate that differences in soil particle size composition and soil properties may affect the sugar and acid levels of the grapes. In addition, soil pH, permeability, and CaO were found to be important factors to be considered in wine making. Soil pH has a strong correlation with glucose, grape pH, and sugar content, and may serve as an indicator when evaluating soil pH in the future. In summary, it was clear that soil physical and chemical properties affect fruit quality.