Effects of a biodegradable liquid film on winter chill protection of winegrape cultivars

Abstract

In China, according to the climatic zoning, more than 90% Vitis vinifera are distributed in areas where the vines must be buried under a layer of soil during winter (vine burial) to protect them from severe winter chill (Li et al., 2006; Wang et al., 2018). Vine burial in winter followed by vine excavation and straightening in spring are difficult and expensive tasks, posing risks to the plants and the environment. Therefore, the goal of this work was to identify a biodegradable liquid film (BLF) suitable for grapevine application to replace vine burial as an alternate strategy to protect against winter chill. We evaluated the influence of BLF spraying on vines after being trained in winter (BLF spraying treatment) and compared it with vine burial (VB). The study evaluated the grapevine death rate of BLF treatment following freezing events in January 2016, and compared germination date, yields, berry quality, and a cost analysis of the two treatments during the winter of 2015 to the spring of 2017 at Heyang Station of Viticulture, NWAFU, in China. The results showed that BLF application can protect some cultivars from winter chill in Heyang and delays bud germination date in cold years. BLF treatment has the opposite trend of reducing sugar and titratable acid content for Cabernet Sauvignon and Italian Riesling, causes higher polyphenols content of berries under most conditions, and requires lower winter vineyard operations costs than VB treatment.