2025, Vol. 6, Issue 2, Part C

The interaction of salicylic acid (SA) with soil organic mulches plays a pivotal role in shaping nutrient bioavailability, root signaling responses, and overall physiological performance of grapevines. Despite extensive literature on the independent roles of SA and mulching, limited research has examined their combined chemical dynamics within soil matrices and their influence on nutrient uptake efficiency in Vitis vinifera. This research investigates the chemical interactions between exogenously applied SA and commonly used organic mulches including straw, leaf compost, wood residues, and farmyard manure and evaluates their integrated impact on nutrient solubility, soil pH modulation, microbial augmentation, and root absorption pathways. SA is known to modulate ion transporters, stimulate systemic acquired resistance, and regulate abiotic stress tolerance; however, its behavior in mulch-amended soils remains poorly understood. Organic mulches, particularly lignocellulosic materials, release humic substances and phenolic polymers that can either synergize or compete with SA in chelating micronutrients such as Fe, Zn, and Mn. This interaction potentially alters root morphology, rhizosphere conductivity, and grapevine nutrient profiles.

Using a controlled field experiment on a mature vineyard block, treatments included SA foliar sprays combined with four mulch types. Parameters such as soil enzymatic activity, nutrient solubility curves, leaf nutrient concentration, chlorophyll index, and yield characteristics were quantified. Results demonstrated that SA–mulch synergy improved nutrient uptake by enhancing rhizosphere redox conditions, increasing root–soil contact surfaces, and promoting beneficial microbial communities. Wood-based mulches exhibited the highest interaction effect due to their rich aromatic compound content. SA application alone improved nutrient uptake moderately, but its combination with organic mulches produced significant increases in N, Fe, and Zn uptake, along with improved berry quality and canopy Vigor. These findings highlight the importance of understanding biochemical interactions between growth regulators and soil amendments for optimizing vineyard nutrient management. The research contributes novel insights into sustainable viticultural practices integrating natural mulches with plant-derived signaling molecules.