Reuse of treated wastewater in viticulture: Can it be an alternative source of nutrient-rich water?

Abstract

Water scarcity is a global problem, which leads to unprecedented pressure on water supply in arid and semi-arid regions. Treating wastewater is an alternative and valuable water resource, therefore its reuse for agricultural irrigation has been growing worldwide since the beginning of the 21^st century. In several regions of the wine-producing countries subject to significant water stress (e.g., Australia, California-USA, Spain), wastewater recycling appears to be the most accessible alternative, both financially and technically, for the agricultural uses that notably not requiring drinking water. Therefore, this research was planned to quantify the contribution of treated wastewater (TWW) to fertilization-needs of the vine, evaluate the impact of irrigation with TWW on the soil, vegetative growth, yield, and wine and grape juice composition. The results provide scientific and technical knowledge on a strategy of water management with high added value. The fertilizer contribution of the TWW would be important, according to the plant's nutrient needs (e.g., in this study 19–39 Unit N, 0.5–1.1 Unit P and 14–28 Unit K ha⁻¹ were supplied with TWW). Ensuring treated wastewater microbiological quality is essential, but without reducing of its nutrients. These nutrients would be a valuable input for crop growth and yield, and could reduce the need to resort for inorganic/synthetic fertilizers. A sustainable use of treated wastewater over the long term would, however, necessitate a good practice guidelines and an integrated vision of treated wastewater quality, crops, irrigation and post-harvest practices.