Table grapes irrigation with treated municipal wastewater in a Mediterranean environment

This study investigated the effect of different water quality regimes [Freshwater (FW), treated wastewater (TW) and alternating FW and TW (FW-TW)] on drip-irrigated table grape yield, quality and microbial contamination. Water and soil samples were analysed. In addition, grape samples were harvested for quantitative and qualitative evaluation. The results showed that the plants irrigated with TW and those irrigated with alternating FW and TW gave 19.57 and 14.95% higher marketable yield, respectively, than plants irrigated with FW. Total soluble sugars, total titratable acidity and sweetness ranged, respectively, between 18.43-20.13, 0.69-0.81% and 21.52-29.19, and were within the desirable levels for table grape harvest. In addition, there was no significant difference in terms of total phenols and mineral composition of berries, leaves, peduncle and pedicels. Finally, table grapes did not present any bacterial contamination which confirm the importance of the adopted irrigation regime for a safe wastewater reuse in agriculture.