Vineyard Restructuration Using Organic–Inorganic Fertilizers and Biostimulants

The problem of vineyard restructuration is that it is a very difficult and time-consuming process. This research investigates a quicker way of replanting an old vineyard using organic–inorganic fertilizers and biostimulants. Specifically, in the experiment, we used a common chemical fertilizer 8-8-8+M.C, an organic fertilizer from leonardite, and two products with beneficial microorganisms (one with mycorrhiza, “Click Nature”, and one with mycorrhiza and trichoderma, “Click Horto”). The process also involved the cleaning of the field of any old vines, a soil analysis, and an analysis for nematodes to determine the soil condition. The old variety consisted of the French variety, Chardonnay, and the new Greek variety, Vidiano, with the rootstock 140RU VCR120. Each treatment was evaluated depending on the plant height, branching ability, leaf size, chlorophyll (SPAD units), and normalized difference vegetation index (NDVI). In addition, verification analyses were performed (soil analyses and qPCR) to examine, in further detail, each treatment and its effect, aiming for an accurate comparison. The qPCR (QLAZEN DNeasy PowerSoil Pro Kit) results showed that the treatment “Click Horto” (mycorrhiza and trichoderma), even though it created an antagonistic condition, resulting in overall lower microbial activity (LI-COR LI-6800 soil CO₂ flux chamber), achieved better plant establishment and development while simultaneously achieving better soil fertility than the other treatments. Moreover, the organic fertilizer achieved higher microbial biodiversity and activity while maintaining a satisfied level of plant development. On the contrary, the chemical fertilizer managed to affect soil health negatively by increasing the soil E.C by 18.1%, total CaCO₃ by 41.1%, and decreasing the organic matter (-11.3%) and microbial activity–biodiversity when compared to other treatments. Finally, this research suggests that vineyard restructuration with the use of the “Click Horto” product could be performed in a quicker and more sustainable and environmentally friendly way by improving the soil health and microbial activity.