The Effects od Foliar Application of Humic Substances on Yield, Quality and Mineral Content of Leaves in the Seedless Sultani Grape Variety (Vitis vinifera L.)

Abstract

Viticulture, which holds a significant place in both the world and our country's agriculture, plays a major role in improving productivity and quality, which also carries great economic value. Fertilization and ensuring that vineyards are nourished to a level that will yield maximum produce are among the foremost practices in this regard. Chemical fertilizers are used intensively in traditional production management, both on the soil and on the leaves. These practices cause pollution of the soil, air, and water resources. This study aims to investigate the effect of foliar application of a humic substance obtained from natural resources. The research was conducted in three replications according to a randomized block design. The humic substance was applied at doses of 0, 0.1%, 0.2%, and 0.3%. According to the results obtained, the effect of foliar application of the humic substance on fresh fruit yield, total soluble solids (TSS), maturity index, and leaf content of K, Ca, Mg, Fe, Zn, Mn, Cu, and B, except for N and P, was found to be statistically significant. By evaluating the effects of all applications, it was concluded that the 0.2% dose yielded the best results, and could be recommended under the conditions of the Aegean Region, Manisa Province, and Alaşehir District.