Effects of Three Reflective Mulches on Yield and Fruit Composition of Coastal New England Winegrapes

Abstract

Three two-year studies evaluated the effects of several reflective mulches on yield and fruit composition in southern New England vineyards. A white reflective woven material (WRM) was tested under vines (covering the herbicide strip) of Chardonnay, Pinot noir, and Merlot in 2004 and 2005. Crushed quahog shells (QS) and a silver aluminized reflective mulch (SRM) were tested under vines of Merlot in 2005 and 2006, and quahog shells were compared with untreated controls on Cabernet franc and Chancellor in 2006 and 2007. WRM increased photosynthetically active radiation (PAR) reflectance into the canopy, but had no measurable impact on fruit composition. SRM improved PAR reflectance into the canopies when compared to the control, but did not impact canopy density, yield, or fruit composition. Rapid soiling and tearing were common problems with the SRM. The addition of a thin layer of quahog shells to the herbicide strip increased soil calcium levels, which resulted in higher pH, and substantially increased Ca:Mg ratio. QS increased canopy density, yield, cluster number, cluster weight, and Brix in some cultivars and some years.