Soil humidity and early leaf water potential affected by water recharge before budbreak in cv. Tempranillo deficitary irrigated during the summer in the D. O. Ribera del Duero

Abstract

The availability of water for irrigation is usually greater at the beginning of spring than in the following months, until the end of summer, in most regions of Spain. The physiological activity and vegetative development of the vine can benefit, from budbreak, from the water in the soil, so it is important to know the real impact that the possible contribution of water at the time of budbreak can have on the moisture content of the soil and the water status of the plant, in situations where the vineyard is usually deficitary watered during the summer, when it suffers greater evapotranspiration demand and needs irrigation to avoid excessive water stress.

The aim is to study the response of soil moisture content (60 cm) and foliar water potential, measured at 7 solar hours on leaves in the shade side, to the application of pre-budbreak irrigation in a vineyard subjected to deficit irrigation (30% ETo) during the summer: T7P vs T07, in cv. Tempranillo, grafted on 110R. The work was carried out over the period 2021-2023, in a vineyard located in the D.O. Ribera del Duero, with vine distances of 3.0 x 1.2 m, trained on vertical trellis and pruned as bilateral Royat cordon, where 4 blocks were established at random, with elementary plots of 48 vines, distributed in 4 rows, of which the 2 central rows were considered for control.

The results show that the moisture content in the first 60 cm of soil was not affected throughout the summer, when weekly deficit irrigation was already applied, by the application of recharge irrigation just at budbreak time. The leaf water potential, however, was slightly favoured by the budbreak recharge until mid-summer, depending on the meteorological conditions of the year. It would be advisable to extend the study temporally and, above all, spatially to different types of soil, considering the impact of the early application of irrigation also on the productive and qualitative response of the vineyard.