Harnessing the benefits of kelp extracts to ensure the sustainability of grape production in today’s climate change era

Abstract

Commercial vineyards encounter various challenges from abiotic and biotic factors, especially as climate change accelerates these issues. To address these challenges, focusing on vine health is key to achieving sustainable grape production. One promising solution is the integration of liquid kelp (macroalgae) extracts, which are rich in natural bioactive substances, into grape production practices. This study investigated the impacts of soil and foliar-applied kelp extracts on the fruit compositional attributes, including Brix, glucose and fructose, malic and tartaric acids, pH, ammonia, YAN, alpha amino compounds, potassium, catechin, tannin, quercetin glycosides, polymeric and total anthocyanins, and micro- and macro-nutrients. The applications were performed on Cabernet Sauvignon through both soil and foliar methods at key phenological stages in mediterranean and on stressed Cabernet Sauvignon affected by leafroll virus and water stress in continental climates. The findings revealed that while soil applications did not lead to significant changes in various metabolites, foliar applications made a notable difference by increasing sugar levels. There is also encouraging potential for enhancements in fruit color and nutrient content, suggesting that further investigation could provide valuable insights into these effects. In continental climates, the results showed that leafroll virus-infected vines did not experience substantial increases in metabolites, although there was a decrease in malic acid, YAN, and potassium levels. On a positive note, both soil and foliar applications contributed to higher levels of tannins and total anthocyanins. This response indicates a protective mechanism against leafroll infection. A similar beneficial response was noted in water-stressed leafroll-infected vines. Moreover, the foliar applications resulted in increased levels of quercetins and malic acid, which are promising outcomes. While foliar applications did not increase levels of micro- and macro-nutrients, soil applications did increase levels of magnesium and ammoniacal nitrogen. Overall, this study highlights that applying kelp extracts could be a valuable strategy for promoting vine growth and attaining sustainable productivity in vineyards, especially in this era of climate change.

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