New challenges for Uruguayan viticulture: water management in the context of a changing climate

Abstract

Climate scenarios in the medium and long term (2010-2070) foresee increased summer rainfall for Uruguay and the region, with increased water deficits and excess episodes. Although at the international level irrigation in viticulture has a long experience and tradition, at the local level (Uruguay), only 10% of the vineyard surface area implements a fixed or complementary system for water supply in their crops. This work aimed to model the crop water requirements for a vineyard in southern Uruguay based on pedo-climatic variables. In addition, the plant response to controlled deficit irrigation was evaluated in two consecutive seasons. The experiment was conducted in a 1.1 ha commercial vineyard in Canelones, Uruguay (34°36'S, 56°14W), during two successive seasons (2020-2021). The additional irrigation (I) treatment was compared against a control (C) without irrigation. A controlled water deficit was established from flowering to harvest. The adjustment in the demand was made as a function of a percentage of crop evapotranspiration. The Kc of the crop was estimated using digital tools. The simulation of the water balance made it possible to evaluate the vineyard water needs. Plants subjected to controlled deficit irrigation showed higher vegetative growth, positively impacting yield and the accumulation of sugars and anthocyanins in the berry. Based on our results, a supplementary water supply, at the right doses and time, allows us to face water deficit situations, positively impacting the productive and economic variables. Knowing the variability in a vineyard is necessary to achieve proper irrigation scheduling and optimize water use. New technologies applied to irrigation are an opportunity for winegrowers to obtain more sustainable vineyards and production.