Review: Use of recycled wastewater for irrigating grapevines

Municipal and winery wastewater can provide a valuable irrigation source in regions where water accessibility is problematic or sustainable disposal of waste is essential. It is imperative, however, that when used for irrigation, water conservation benefits are not compromised by a decline in soil and plant health. To date, published literature investigating the use of wastewaters for grapevine production is restricted to a limited set of studies. Globally, wastewater usage within the horticultural sector, including winegrape production, is increasing. It is necessary, therefore, to better understand the short- and long-term implications of such practice. Although wastewaters may contain a range of organic and inorganic pollutants, this review focuses primarily on specific issues associated with high salt loading that is typical under wastewater irrigation. Managing salt, in particular sodium (Na+) and potassium (K+), in wastewater will be necessary in order to maintain the soil physical, chemical and biological health in the long term. Soil structural degradation resulting from a high concentration of exchangeable monovalent cations is of major concern where wastewater is being used for irrigation. This review will address (i) the effect of wastewater irrigation on vine performance and grape quality; (ii) chemical and physical changes in soils irrigated with municipal and winery wastewater; and (iii) management practices that may assist in ameliorating vineyard soils abundant in monovalent cations as a result of wastewater irrigation.