ECOLOGICAL TABLE GRAPE PRODUCTION IN TURKEY

The organic (ecologic-biologic) agricultural practices in Turkey began in 1985 with organic raisins and dried figs demand of European countries. As of 2015, 1829291 tons of organic products from 197 different products, which comprise grapes, in 515268 ha, are produced by 69967 farmers. Currently, the number of registered enterprises operating in organic agriculture is over 1500. As in the entire in world and in Turkey, the share of organic production in grape production is increasing. Organic grape production is carried out in 10645 ha area in Turkey. This amount constitutes approximately 2.3% of the total grape production area in Turkey. Organic grape is the second major product of Turkey export, and the export share of organic products in recent years is increased to 20-30%. The share of the organic table grape production in total organic grape production is an increasing trend and the studies in this direction are continuing

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 reduced soil functionality in European vineyards

Improper or excessive land preparation methods in vineyards before planting can have a considerable impact on soil functionality. They include excessive levelling and deep ploughing leading to disturbances of the natural contour of slopes and destruction, truncation and burial of soil horizons. Manipulations may significantly modify chemical, physical, biological and hydrological balance of soils. Problems that may arise from these interventions relate to the reduction of organic substances, enrichment of calcium carbonate and soluble salts, impacting development and health of grapevines. Reduced water retention capacity can lead to increased water stress during dry season, decreased water permeability and circulation of oxygen in the soil, increased runoff volume, surface erosion and landslide risk, reduced biodiversity and limitation of biochemical processes (organic matter mineralization, bioavailability of nutrients, etc.). Soil degradations can lead to the loss of soil functionality even after the planting as a result of accelerated erosion, compaction by agricultural vehicles, excessive loss of organic matter and nutrients, and the accumulation of heavy metals such as copper. In both conventional and organic vineyards, it is quite common to have areas with reduced soil functionality that have negative impact on vine health and grape production and quality. In the framework of the Core organic RESOLVE project, a study was conducted in organic vineyards showing areas with reduced and good soil functionality. Degraded soils resulted in significantly lower amounts of grapes. The chlorophyll index (SPAD) of the grapevine during veraison was significantly lower in areas of degraded soils compared with the situation in areas of the same vineyard with non-degraded soils. In general, causes of soil malfunctioning were related to a lower fertility, including reduced organic carbon, total nitrogen and cation exchange capacity, higher concentrations of carbonates, and increased stoniness in the topsoil. Degraded soils showed lower structure quality and rooting depth limited by shallow saprolite or horizon features such as compaction, scarce fertility and high content of carbonates. The soils in the non-degraded areas showed significant higher content of total nitrogen and higher carbon/nitrogen ratios, thus a better stability of organic matter. On the other hand, biological diversity and activity, monitored by different proxies (microarthropods, nematodes, enzymes, organic matter turnover by Tea bag index) in some vineyards, all managed organically, did not show any clear and significant differences between degraded and not degraded areas. Similarly, no clear difference in overall microbial diversity indices (Shannon, Simpson) and diversity evenness (Pielou) were observed between non-degraded and degraded areas. All indices were relatively high and indicative for rich occurrence of abundant and rare microbial species, high diversity and low abundance of individual species and high species evenness

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

Effects of soil erosion on agro-ecosystem services and soil functions: A multidisciplinary study in nineteen organically farmed European and Turkish vineyards

This multidisciplinary research work evaluated the effects of soil erosion on grape yield and quality and on different soil functions, namely water and nutrient supply, carbon sequestration, organic matter recycling, and soil biodiversity, with the aim to understand the causes of soil malfunctioning and work out a proper strategy of soil remediation. Degraded areas in nineteen organically farmed European and Turkish vineyards resulted in producing significantly lower amounts of grapes and excessive concentrations of sugar. Plants suffered from decreased water nutrition, due to shallower rooting depth, compaction, and reduced available water capacity, lower chemical fertility, as total nitrogen and cation exchange capacity, and higher concentration of carbonates. Carbon storage and organic matter recycling were also depressed. The general trend of soil enzyme activity mainly followed organic matter stock. Specific enzymatic activities suggested that in degraded soils, alongside a general slowdown in organic matter cycling, there was a greater reduction in decomposition capacity of the most recalcitrant forms. The abundance of Acari Oribatida and Collembola resulted the most sensitive indicator of soil degradation among the considered microarthropods. No clear difference in overall microbial richness and evenness were observed. All indices were relatively high and indicative of rich occurrence of many and rare microbial species. Dice cluster analyses indicated slight qualitative differences in Eubacterial and fungal community compositions in rhizosphere soil and roots in degraded soils. This multidisciplinary study indicates that the loss of soil fertility caused by excessive earth movement before planting, or accelerated erosion, mainly affects water nutrition and chemical fertility. Biological soil fertility is also reduced, in particular the ability of biota to decompose organic matter, while biodiversity is less affected, probably because of the organic management. Therefore, the restoration of the eroded soils requires site-specific and intensive treatments, including accurately chosen organic matrices for fertilization, privileging the most easily decomposable. Restoring soil fertility in depth, however, remain an open question, which needs further investigation