Influence of vine water status on aboveground biomass production and partitioning

Abstract

Water availability is considered a determinant factor for grape-growing sustainability since vineyard water relations critically impacts on vine performance and grape and wine composition. Improving water use efficiency (WUE) is therefore of crucial importance for a sustainable viticulture in Mediterranean and semi-arid regions. In a previous work, we defined ranges and relationships for biomass production and partitioning among vines of several cultivars at vineyard scale, using an extensive database of vegetative growth and yield data. In this study those ranges and relationships are used as a tool for evaluating the influence  of  seasonal  vine  water  status  on  biomass  production  and  partitioning  in  vineyards  throughout semi-arid regions in Spain (Navarra, Cataluña, Baleares and Valencia). Aboveground vegetative growth and yield data were transformed to biomass values using allometric relationships and partitioning among vegetative and reproductive structures was calculated. Biomass production and partitioning in the vineyards fell within the confidence ranges of the reference relationships. Water availability positively influenced biomass production, increasing it up to a 50% respect rain-fed vineyards. Moreover, seasonal stem water potential differences of 0.1 MPa were needed to modify aboveground biomass production in 100-150 g·vine^-1. Partitioning was also affected, as lower water availability favored up to a 9-12% higher biomass allocation to bunches in rain-fed vineyards. Overall, the results obtained provide a tool to better evaluate water use efficiency in vineyards.