Canopy management and water use efficiency in vineyards under Mediterranean semiarid conditions

Abstract

One of the main objectives in Mediterranean vineyards is the water use efficiency due to its scarcity. During the growing season, total available water is significantly lower than the evaporative demand, being this a limiting factor for quality production. Beside other factors, the choice of an adequate training system can help mitigate this negative effect in regard with soil-plant hydric consumption. The use of porous systems can help plants establish a better leaf distribution inside the clusters area, providing more space and enhancing certain physiological processes, both in leaves and berries (de la Fuente et al., 2013), and causing a better utilization of natural resources.Water consumption, dynamics and hydric relations in plants (water potential) and soil (soil water tension and capacity) have been studied on three different systems: sprawl system with 12 shoots m–1 (S1); sprawl system with 18 shoots m–1 (S2) and verti- cal positioned system or VSP with 12 shoots m–1 (VSP1). Yield, dry matter partitioning and berry and must composition have also been obtained at the maturity stage.The main objective of this study was to show the differences in consumption and water use efficiency due to different canopy managements, and to quantify these effects on yield, berry and must composition.The results showed that the vertical system (VSP1) benefited less from total available water at medium level (20; 30 and 50 cm) in the profile soil (0.5–1.5% available water vol.), in comparison with non-positioned and free systems (S1 and S2). On the other hand, S1 and S2 treatments caused more stress to the plant at midday from flowering to veraison (8–10%), but not during ripening. Sprawl system (S1) helps produce more balanced plants compared to VSP1, because it obtains higher number (and weight) of main leaves by shoot, increasing the number of secondary shoots and maximizing the canopy volume. No dif- ferences were observed in the number of clusters, berry size or yield between VSP1 and S1, but higher crop load treatment (S2) showed an evident yield increase (16%) at harvest.Berry and must composition did not change (Brix, pH and total acidity) much, while the composition of anthocyanins improved with low exposure and non-positioned systems (S1 and S2).In addition, both positive effects of sprawl treatments (crop load and training system) resulted in better yield and quality in Mediterranean semiarid conditions under the same inputs (sun, water and soil), causing higher efficiency of natural resources.