Effect of Irrigation using Diluted Winery Wastewater on Vitis vinifera L. cv. Cabernet Sauvignon in a Sandy Alluvial Soil in the Breede River Valley – Vegetative Growth, Yield and Wine Quality
C.L. Howell, P.A. Myburgh, E.L. Lategan, C. Schoeman, J.E. Hoffman
The re-use of winery wastewater for irrigation was investigated in a field trial with micro-sprinklerirrigated
Cabernet Sauvignon/99Richter in the Breede River Valley region of South Africa. Irrigation
with winery wastewater diluted with river water to 100, 250, 500, 1 000, 1 500, 2 000, 2 500 and 3 000
mg/L chemical oxygen demand (COD) was compared to irrigation with river water. Under the prevailing
conditions, plant water status did not respond to irrigation using diluted winery wastewater. Leaf and
shoot element contents did not respond consistently to irrigation using diluted winery wastewater.
There were no differences in vegetative growth or yield or juice characteristics, with the exception of
juice pH. Consequently, water use and water status of the grapevines also were not affected. The results
indicate that a summer interception crop may increase the evapotranspiration of vineyards substantially.
The irrigation of grapevines using diluted winery wastewater did not have detrimental effects on wine
colour and sensory wine characteristics, and the grapevines did not respond to the COD level per se. This
indicates that sufficient aeration occurred between irrigations, which allowed organic carbon breakdown.
The low salinity and sodicity levels in the diluted winery wastewater could be a further explanation of why
the grapevines did not respond to the wastewater irrigation. In heavier soils, regions with lower winter
rainfall, situations where the winery wastewater contains more potassium or where no interception crop is
cultivated during summer, grapevine responses may be more pronounced.
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