ReSolVe project – Restoring optimal Soil functionality in degraded areas within organic Vineyards

In both conventional and organic European vineyards, it is quite common to have areas characterized by problems in vine health, grape production and quality. These problems are very often related to sub-optimal soil functionality, caused by an improper land preparation before vine plantation and/or management. Different causes for soil malfunctioning can include: poor organic matter content and plant nutrient availability (both major and trace elements); imbalance of some element ratios (Ca/Mg, K/Mg, P/Fe, and Fe/Mn); pH; water deficiency; soil compaction and/or scarce oxygenation. Fertility related problems can often be compensated in conventional settings with externally introduced fertilizers that are not permitted in organic vineyards. ReSolVe is a transnational and multidisciplinary research project aimed at testing the effects of selected agronomic strategies for restoring optimal soil functionality in degraded areas within organic vineyard. The term "degraded areas within vineyard" means areas showing reduced vine growth, disease resistance, grape yield and quality. These areas may have lost their soil functionality because of either an improper land preparation, or an excessive loss of soil organic matter and nutrients, erosion and/or compaction. The project, financed by Core-Organic plus program of the ERA-NET plus action (2015-2018), aims at identifying the main causes of the soil functionality loss and testing different organic recovering methods. The different restoring strategies will implement: i) compost, ii) green manure with winter legumes, iii) dry mulching with cover crops. The strategies will be tested according to their efficiency to improve: i) plant and roots growth and well-being; ii) grape yield and quality; iii) quality of soil ecosystem services and their stability over the years; iv) better express of the “terroir effect”, that is, the linkage of wine quality to the environmental characteristics of the cultivation site. The project involves 8 research groups in 6 different EU countries (Italy, France, Spain, Sweden, Slovenia, and Turkey), with experts from several disciplines, including soil science, ecology, microbiology, grapevine physiology, viticulture, and biometry. The experimental vineyards are situated in Italy (Chianti hills and Maremma plain, Tuscany), France (Bordeaux and Languedoc), Spain (La Rioja) and Slovenia (Primorska) for winegrape, and in Turkey (Adana and Mersin) for table grape. The restoration techniques and the monitoring methodologies developed and tested during the ReSolVe project will be described in specific final guidelines. The restoration techniques will be accessible for all the European farmers and will be low cost and environmental-friendly. A protocol of analyses and measurements between the all partners will allow an effective and comparable monitoring of vineyard ecosystemic functioning in European countries

CAUSES OF SOIL MALFUNCTIONING IN DEGRADED AREAS OF EUROPEAN AND TURKISH VINEYARDS

WOS: 000492704800002A study was carried out in nineteen vineyards of five countries, well representative of major viticultural districts, which showed areas with fertility problems, consequence of strong soil erosion occurred during either pre-planting or ordinary cultivation. The comparison between degraded and non-degraded areas highlighted that the soil features limiting water nutrition and enhancing potential water stress were the most frequent discriminant soil conditions. Low nitrogen availability was the second most important cause of soil malfunctioning, together with low organic matter content. The degradation was also reflected in the very low values of the C/N ratio, pointing to a difficulty of microbiota in synthetizing humus. Other limiting factor were excessive lime content and poor drainage. Also nutrient unbalance or toxicity and low cation exchange capacity sporadically occurred. Since physical and hydrological limitations are hardly modifiable, especially in depth, the study underlines the difficulties to restore the fertility of degraded soils, and suggests caution in planning new vineyards

Effect of organic treatments on soil carbon and nitrogen dynamics in vineyard

The work aims to investigate the effects of different soil management strategies on carbon sequestration and total nitrogen in areas of vineyards suffering from loss of soil functionality. Treatments, selected for inter-row management, to re-install soil functionality were based on compost or other organic amendments (COMP), green manure (GM), and dry mulching (DM) strategies using winter legumes and cereals. Cover crops were seeded in fall and mown in late spring, leaved in the ground for mulching in DM or incorporated into the uppermost soil layers in GM. Such approaches were investigated in six vineyards in Italy, six in France, and two vineyards in Slovenia and Turkey. The results showed that COMP significantly increased total organic carbon (TOC) and total nitrogen (Ntot) in the topsoil after one year of application. Also DM tends to increase significantly TOC in the topsoil, but only after two years. Modelling 20-year carbon stock dynamics in Italy vineyards, the average increase resulted 0.49, 0.34, 0.21 and 0.03 Mg C ha-1 yr-1 for COMP, DM, GM and control, respectively

Effects of soil degradation and organic treatments on vegetative growth, yield and grape quality

Delimited degraded soil areas caused by an improper land preparation before vine plantation and or management can be observed in conventional and organic European vineyards. Soil malfunctioning including: poor organic matter content, imbalanced nutritional status, altered pH, water deficiency, soil compaction and/or scarce oxygenation. The goal of the present study was to compare the effects of some agronomic strategies to restore optimal soil functionality in degraded areas in organic commercial vineyards located in five countries, and to evaluate the impact of these soil management practices on vegetative growth, yield and grape quality parameters. Grapevines located in non-degraded soils showed higher vegetative growth and yield, and lower total soluble solids in grapes. Generally, there were no significant differences in vegetative growth, yield and grape quality among the soil management strategies in degraded areas