Physiological response to irrigation and its application period of cv. Tempranillo in the A.O. Ribera del Duero

Abstract

The physiological advantages that irrigation can provide in the growing of vines heavily depend on the way it is applied at each site. In this sense, it is desirable to check the effects of irrigation in specific areas and for certain varieties, especially considering the obvious existing water stress situations, compounded in many cases with the situation of climate change, in order to try to adopt adequate and efficient irrigation strategies in each case.

Throughout the 2009-2011 period it has been studied the application of deficit irrigation in two different periods of the summer season, through the following experimental treatments: rainfed (R0), 20% ETo from growing stop of main shoots (R1) and 20% ETo from veraison (R2). The trial was developed with vines of Tempranillo on 110R rootstock, planted in 1999 and trellised as a bilateral Royat cordon. The vine distances were 3 m x 1.5 m (2,222 plants/ha). The study was conducted in a vineyard located at 900 m altitude in a shallow and not very fertile soil, in Castrillo de Duero (Valladolid, Spain), belonging to the A.O. Ribera del Duero. The work has been focused on the water status and physiological response of vineyard to irrigation and to the variation of its application period during the summer.

The results show that the measurement of pre-dawn leaf water potential has shown in general the different water situation of the irrigation treatments with respect to the non irrigated one, but the discrimination between periods of watering was not always clear. The stomatal conductance and the net photosynthesis have shown a plant response to atmospheric demand in accordance with the water availability generated by irrigation, with higher rates of R1 until the start of watering application of R2, and similar rates of R1 and R2 during the simultaneous irrigation of R1 and R2, with statistically significant differences with respect to non irrigation, R0. Maximum plant leaf development has not substantially been modified by the water regimes established, whereas global productivity of plant has been favoured by the water applied by irrigation, as a result of water status and gas exchange rates more favourable to such treatments with respect to the rainfed treatment.