Spatio-temporal variability in soil water content (SWC) in a vineyard can affect spatial variability in yield and berry composition. The objectives of the study were to understand temporal stability of spatial variability in yield and berry composition within a vineyard and quantify the contribution of spatial variability in SWC to the overall spatial distribution in yield and berry composition. Yield, Brix, tannin and total phenols were collected at the end of berry ripening stage for 135 georeferenced points in 2012, and 147 points in 2013 and 2014 within a Merlot vineyard in Gansu Province, China. Volumetric SWC at those points was measured multiple times at different growth stages of each year. Spatial variation of yield showed moderate and similar spatial heterogeneity for different years, but the variation in berry composition was not consistent among the three years. Spatial variation in yield in 2012 and 2013 could be best described by the exponential variogram model, while there was no spatial structure of yield in 2014. In addition, yield of low SWC of 0 – 20 cm depth was higher than that of high soil water content, while opposite results were found for 40 – 60 cm soil depth. Spatio-temporal distributions of SWC explained more than 35% of total variation in yield and berry composition in a relatively dry year of 2012 but less than 10% in a relatively wet year of 2014. The contribution of spatio-temporal distributions of SWC to the spatial variability in yield and berry composition tended to vary depending on different field and weather conditions. This study provides a basis for developing site-specific management measures for better economic return of growers.
- ©2017 by the American Society for Enology and Viticulture