Effect of foliar potassium spraying on productivity and quality of grape fruits (Vitis vinifera) under different irrigation levels

. Sustainable strategies to mitigate water stress and enhance fruit quality are therefore of immense industrial interest. This study investigated the efficacy of foliar potassium (K) application as a practical agricultural strategy to ameliorate the adverse effects of different irrigation levels on grape productivity and, more importantly, on key quality attributes relevant to the food processing industry. A field experiment was conducted using a factorial arrangement based on a Randomized Complete Block Design (RCBD). Grapevines were subjected to three irrigation levels (۱۰۰%, ۷۵%, and ۵۰% of crop evapotranspiration - ETc) and three concentrations of foliar potassium (۰, ۱%, and ۲% K۲O). Parameters measured included yield, cluster weight, and a comprehensive set of quality traits: total soluble solids (TSS), titratable acidity (TA), pH, berry firmness, and the concentration of anthocyanins and total phenolics. Water deficit significantly reduced yield but enhanced most quality parameters. The ۵۰% ETc treatment led to a notable increase in TSS, TSS/TA ratio, and anthocyanin content. Foliar potassium application, particularly at ۲%, effectively mitigated yield losses under stress and synergistically improved quality. The interaction between ۷۵% ETc and ۲% K spray resulted in an optimal balance, achieving a yield comparable to full irrigation while significantly boosting TSS, phenolic content, and color intensity—attributes highly sought after for premium wine and juice production. The integrated management of deficit irrigation (۷۵% ETc) and foliar potassium nutrition (۲%) presents a viable and sustainable strategy for the grape industry.

کلیدواژه ها:

water stress ، Potassium Fertilization ، fruit quality ، Bioactive compounds ، food processing ، Sustainable Viticulture