Organic Viticulture Research Articles

Differentiating the effects of organic management, pesticide reduction, and landscape diversification for arthropod conservation in viticulture

Biodiversity loss is a main challenge for agricultural sustainability. Major drivers include local management and landscape simplification. Therefore, conservation measures aim to increase organic agriculture, reduce pesticide use, and increase the proportion of semi-natural habitats (SNH). Yet, it is important to understand the effects of such measures. We investigate how arthropod biomass, taxa richness, and community composition in Malaise trap samples are affected by organic management, pesticide use, and SNH in the landscape. The 32 studied vineyards were chosen in a crossed design of management (organic vs. conventional) and pesticide use (regular vs. reduced) along a gradient of landscape composition. Pesticide reduction by 55% was obtained by including half of the vineyards with fungus-resistant grape (FRG) varieties. Malaise trap samples were weighed and arthropods identified using metabarcoding. Surprisingly, biomass was almost one-third higher in conventionally managed vineyards compared to organic ones. Taxa richness increased by more than one third when the proportion of SNH in a radius of 1,000 m in the surrounding landscape increased from zero to 50%. Diptera richness tended to be 4% higher in conventionally managed vineyards and the richness of Hymenoptera was 9% higher in FRG varieties. Community composition changed with the proportion of SNH and differed between organic and conventional management. Overall, organic viticulture was not effective to enhance the arthropod community, which was dominated by flying insects in our study. Agricultural policies should therefore rather preserve and promote SNH in the surrounding in order to promote arthropod biodiversity in viticultural landscapes.

Arthropods on grapes benefit more from fungicide reduction than from organic farming.

Pesticides are considered main contributors to global arthropod declines and therefore may decrease the provision of ecosystem services such as natural pest control. Organic farming and cultivating pest- and disease-resistant varieties can allow pesticide applications and their impacts on nontarget organisms and the environment to be reduced. We investigated the effects of organic versus conventional management and fungus-resistant versus susceptible wine grape varieties on arthropod biodiversity and pest control of grape berry moths in 32 vineyards in the Palatinate region, Germany. Hazard quotients of applied pesticides were calculated for each vineyard. The cultivation of fungus-resistant varieties led to significantly reduced hazard quotients and in turn enhanced abundances of natural enemies, particularly theridiid and philodromid spiders. Unexpectedly, organic management resulted in higher hazard quotients than conventional management and reduced numbers of natural enemies, particularly earwigs. Pest predation rates showed no significant differences between grape varieties or management types. Widespread benefits of organic management on arthropod biodiversity found in other crops were absent in our viticultural study region. This is likely due to the dominant role of fungal diseases in viticulture, which requires high numbers of fungicide treatments under both conventional and organic viticulture. Thus, fungicide reduction through the cultivation of fungus-resistant grape varieties is one key element to fostering the abundance of arthropods in general and beneficial arthropods in particular. Beyond vineyards, this is potentially relevant in numerous other crop types. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Some aspects of the legal regulation of state support for the production of organic crop production

The article examines the peculiarities of the legal regulation of state support for the production of organic crop production in Ukraine. The works of domestic scientists dealing with the issues of state support for the production of organic products were studied. Conducted legal analysis of Ukrainian and European legislation in the specified area. The author concludes that the issue of state support for the production of organic crop production in Ukraine is insufficiently regulated. To date, obtaining "real" funds for organic production is possible only through participation in grant programs. Their goal is to preserve and strengthen the capacity of the organic sector of Ukraine in the medium and long term, as well as to support producers of organic products whose areas are located in the territory of Zhytomyr, Kyiv, Chernihiv, Kharkiv and Sumy oblasts, which were occupied during the first months of the invasion, or the territory other areas affected by active hostilities. At the state level, the necessary conditions (both legal and financial) must be created to ensure the further development of organic production of crop production, which will contribute, among other things, to ensuring food security of our country. The author considers it appropriate to amend Article 8 of the Law of Ukraine "On Basic Principles and Requirements for Organic Production, Circulation and Labeling of Organic Products" in the following version: "state support can be provided to operators within the framework of the state target program for the development of organic production and relevant regional programs." In addition, we propose to supplement Clause 17-2.9 of Article 17-2 of the Law of Ukraine "On State Support of the Agriculture of Ukraine" with a subsection to provide for specific measures of state support for such branches of crop production as the harvesting of organic plants, organic viticulture and cultivation of organic grain crops. Also, the Law should provide for other types of state support for organic production, in particular regarding personnel and informational and advisory support.

Biodiversity conservation, ecosystem services and organic viticulture: A glass half-full

Organic farming is a promising but still debated option to ensure sustainable agriculture. However, whether organic farming fosters synergies or mitigates tradeoffs between biodiversity, ecosystem services and crop production has rarely been quantified. Here, we investigate relationships between multitrophic diversity (14 taxa above and belowground), yield, natural pest control and soil quality (14 proxies of ecosystem services) in organic and conventional vineyards along a landscape gradient. Organic farming enhanced biodiversity and pest control, but decreased wine production. Compared to conventional systems, multitrophic diversity was 15 % higher, and pest control services were 9 % higher in organic systems, while wine production was 11 % lower. Regardless of management type, we found a strong tradeoff between wine production and pest control, but not between wine production and biodiversity. The landscape context was not a strong moderator of organic farming effects across taxa groups and ecosystem services, but affected specific taxa and ecosystem services, especially natural pest control. Our study reveals that wine production and biodiversity conservation do not necessarily exclude each other, which implies the existence of a safe operating space where biodiversity and wine production can be combined. We conclude that organic farming can contribute to improve the sustainability of viticulture, but needs to be complemented by management options at the local and landscape scales in order to fully balance biodiversity conservation with the simultaneous provision of multiple ecosystem services.

Comparing the Carbon Footprint of Conventional and Organic Vineyards in Northern Italy

The carbon footprint is an index used to assess the impact of an activity in terms of greenhouse gas emissions. Viticulture contributes to greenhouse gas emissions due to the use of fuels, fertilizers and pesticides, and the consequent soil erosion. Organic viticulture differs from conventional viticulture, mainly because of the absence of synthetic products, the soil tillage, and the level of organic carbon in the soil. The purpose of the study was to determine the actual differences between conventional and organic vineyard management in terms of greenhouse gas emissions, comparing multiannual data from 25 wineries in northern Italy. No statistically significant differences were found between the overall mean values of conventional and organic management. In organically farmed vineyards, a higher incidence of fuel consumption was observed, while in conventionally farmed vineyards higher emissions were observed, due to the use of such products as pesticides and fertilizers. No differences were found between the two management systems in terms of emissions resulting from direct fertilizing. Further assessment of the potential sequestration of organic fertilizer would be necessary.

Copper Bioavailability and Leaching in Conventional and Organic Viticulture under Environmental Stress

The continuous use of Cu-based fungicides in viticulture has caused Cu accumulation in soils, which represents a major environmental and toxicological concern. The purpose of this study was to verify whether the organic management would be more resilient to temperature and moisture stresses in comparison to conventional practices. Two organic and two conventional vineyard soils, contrasting in pH, were exposed for six months to temperature stress (29 °C), moisture stress (10% water holding capacity—WHC), and combined stresses (29 °C—10% WHC). Main soil properties, Cu speciation, bioavailability, and leaching were monitored before and after 6 months’ incubation. Results confirm that the increase of temperature caused a decrease in both total organic carbon (TOC) and dissolved organic carbon (DOC) (up to 19% and 49%, respectively), a decrease in available ammonium, and an increase in nitrate. Moisture stress tends to mitigate some of these changes. Despite that, changes of Cu bioavailability and leaching were limited and rarely significant. Moreover, no regular trends between conventional and organic management could be observed. Changes in soil pH and total N (TN) appeared as the most influencing properties to regulate Cu behavior in vineyard soils. Calcareous soils were more resistant to environmental stresses compared to acid soils, regardless of the type of management (conventional or organic).

Role of Agricultural Management in the Provision of Ecosystem Services in Warm Climate Vineyards: Functional Prediction of Genes Involved in Nutrient Cycling and Carbon Sequestration.

(1) Background: Maintaining soil fertility and crop productivity using natural microbial diversity could be a feasible approach for achieving sustainable development in agriculture. In this study, we compared soils from vineyards under organic and conventional management by predicting functional profiles through metagenomic analysis based on the 16S rRNA gene. (2) Methods: The structure, diversity and predictive functions of soil bacteria related to the biogeochemical cycle of the soil were analyzed, including oxidative and hydrolytic C-cycling enzymes, N-cycling enzymes and P-cycling enzymes. The inter-row spontaneous vegetation in the organic vineyards was also characterized. (3) Results: A clear effect of the farming system (organic vs. conventional) and cover management (herbicides plus tillage, mowing only and mowing plus tillage) on bacterial beta diversity and predicted functions was evidenced. While conventional viticulture increased the potential capacity of the soil to regulate the cycling of inorganic forms of N, organic viticulture in general enhanced those functions involving organic N, P and C substrates. Although the soil bacterial community responded differently to contrasting soil management strategies, nutrient cycling and carbon sequestration functions remained preserved, suggesting a high bacterial functional redundancy in the soil in any case. However, most of the predicted bacterial functions related to soil organic matter turnover were enhanced by organic management. (4) Conclusions: We posit the potential for organic viticulture to adequately address climate change adaptation in the context of sustainable agriculture.

Efficacy of Conventional and Organic Insecticides against Scaphoideus titanus: Field and Semi-Field Trials

Scaphoideus titanus is the main vector of phytoplasmas associated with Flavescence dorée (FD), one of the most serious threats to viticulture in many European countries. To minimize the spread of this disease, mandatory control measures against S. titanus were decided in Europe. In the 1990s, the repeated application of insecticides (mainly organophosphates) proved to be an effective measure to control the vector and the related disease in north-eastern Italy. These insecticides and most of the neonicotinoids were recently banned from European viticulture. Serious FD issues detected in the recent years in northern Italy could be related to the use of less effective insecticides. Trials aimed at evaluating the efficacy of the most used conventional and organic insecticides in the control of S. titanus have been performed in semi-field and field conditions to test this hypothesis. In efficacy trials, carried out in four vineyards, etofenprox and deltamethrin proved to be the best conventional insecticides, while pyrethrins were the most impactful among organic insecticides. Insecticide residual activity was evaluated in semi-field and field conditions. Acrinathrin showed the most significant residual effects in both conditions. In semi-field trials, most of the pyrethroids were associated with good results in terms of residual activity. However, these effects declined in field conditions, probably due to high temperatures. Organic insecticides showed poor results in terms of residual efficacy. Implications of these results in the context of Integrated Pest Management in conventional and organic viticulture are discussed.

Disease Forecasting for the Rational Management of Grapevine Mildews in the Chianti Bio-District (Tuscany)

Downy and powdery mildews are major grapevine diseases. In organic viticulture, a few fungicides with protectant activities (copper and sulphur in particular) can be used, and their preventative application frequently leads to unneeded spraying. The adoption of an epidemiological disease forecasting model could optimise the timing of treatments and achieve a good level of disease protection. In this study, the effectiveness of the EPI (Etat Potentiel d'Infection) model in predicting infection risk for downy and powdery mildews was evaluated in nine organic vineyards located in Panzano in Chianti (FI), over a 2-year period (2020-2021). The reliability of the EPI model was investigated by comparing the disease intensities, the number of fungicide sprayings, the quantities of the fungicides (kg/ha), and the costs of the treatment achieved, with or without the use of the model, in a vineyard. The results obtained over two seasons indicated that, in most cases, the use of the EPI model accurately signalled the infection risk and allowed for a reduction in the frequency and cost of spraying, particularly for powdery mildew control (-40% sprayings, -20% costs compared to the farmer's schedule), without compromising crop protection. The use of the EPI model can, therefore, contribute to more-sustainable disease management in organic viticulture.

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In the field of agroindustry, the most attention is paid to the development of ecofriendly technologies, which allow to improve the efficiency of natural resources in sustainable agriculture, preserving the environment, as well as to obtain highquality, environmentally friendly, and safe products. Currently, organic viticulture and biodynamic winemaking are rapidly developing and demanding areas of winemaking. In light of these factors, it makes sense to cultivate grape varieties that are resistant to cold, fungal diseases, and pests (in particular, the Charentsi variety). Under different conditions, the microbiological state, physicochemical parameters, organic acids content, and color characteristics of Charentsi grapes were examined. We studied the physicochemical parameters of wines made by using different methods. The possibility of making ecologically clean rosé wines from this grape variety was assessed, using it as a raw material.

Potential of Cover Crops to Control Arthropod Pests in Organic Viticulture


 Plant diversity has the potential to conserve beneficials and thereby naturally controlling arthropod pests. Beneficials’ activity can be increased by pollen-rich plant species. Here we aimed to develop innovative viticultural systems that naturally control arthropod pests, by increasing plant diversity within vineyards planting of selected cover crops. The experimental vineyards were set-up in Chablis (France), Piacenza (Italy), Murfatlar (Romania), Manče (Slovenia), Valencia (Spain) and Nyon (Switzerland). Each vineyard was divided in a traditional and innovative subplot and monitored in 2019 and 2020. The effect of cover crops on arthropods was assessed according to a common protocol using visual samplings and specific traps. Analysing the obtained data, there were no statistically significant differences in the abundance of sampled arthropod pests in the innovative and the traditional systems. Yet, two of five studied pest species tended to be less abundant in the innovative systems. Regarding arthropod beneficials, flying parasitoids and bees tended to benefit from the planting of cover crops in the innovative compared to the traditional systems. Alike, predators such as spiders and carabids were more abundant in vineyards with understorey vegetation. Overall, the arthropod biodiversity seems to benefit from the planting of cover crops but without necessarily favouring pest suppression.

Organic viticulture leads to lower trade-offs between agroecosystem goods but does not improve overall multifunctionality

CONTEXTAssessing the multifunctionality of agroecosystems is crucial to design more sustainable farming systems. While it is known that organic farming benefits biodiversity and ecosystem services, how organic farming affects their multifunctionality, including agronomical, ecological as well as economic dimensions, remains poorly explored. OBJECTIVEIn this study, we investigated how individual indicators regrouped into agroecosystem goods of vineyards respond to farming systems and landscape composition. We also explored how ecosystem services resulting from agroecosystem goods respond to farming systems and landscape composition. In addition, we evaluated trade-offs and synergies between agroecosystem goods as well as between ecosystem services for each farming systems. METHODWe quantified 14 indicators corresponding to five agroecosystem goods (biodiversity conservation, soil organic matter decomposition, pest control, wine production, margin) in 20 pairs of organic and conventional vineyards. RESULTS AND CONCLUSIONOur study reveals that organic farming did not improve agroecosystem multifunctionality compared to conventional farming but led to lower trade-offs between agroecosystem goods. We found that organic systems increase supporting and regulating services but had lower provisioning service compared to conventional systems. Indeed, organic vineyards had multiple beneficial effects including higher pest control, lower production costs but produced less wine. Our results indicate a strong trade-off between pest control and wine production in both systems. In addition, conventional systems supported a negative trade-off between biodiversity conservation and wine production which was not the case of organic systems. SIGNIFICANCEOur study provides key information to further design farming systems that combine ecological, economical and agronomical performances. Further investigations are now needed to identify which combined management options maximize multiple performance of agroecosystems independently of certifications and across scales.

Comparison of Ion Chromatography Conductivity Detection (IC-CD) and Ion Chromatography Inductively Coupled Plasma Mass Spectrometry (IC-ICP-MS) for the Determination of Phosphonic Acid in Grapevine Plant Parts, Wine, and Soil.

Potassium dihydrogen phosphonate had been allowed as a plant strengthener in organic viticulture in the European Union only until 2013, supporting the control of grapevine downy mildew. Therefore, low or nondetectable levels are a prerequisite for marketing of organic wines and, consequently, validated analytical methods are of major interest. Herein, two methods based on ion chromatography conductivity detection (IC-CD) or ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) for the determination of phosphonic acid (H3PO3) from 14 different plant matrices of Vitis vinifera L., wine, and soil were developed, validated, and compared. Extraction recoveries ranged from 95.1 to 99.3%. Limits of quantification (LOQ) ranged in liquid and solid samples from 3.8 to 16.8 μg/kg and 0.08 to 2.41 mg/kg for ICP-MS detection and from 39.9 to 593.7 μg/kg and 3.51 to 58.7 mg/kg for CD, respectively. Data on a current anonymized selection of 100 conventionally and 30 organically produced wines are briefly presented to demonstrate the suitability of the method.

COS-OGA Applications in Organic Vineyard Manage Major Airborne Diseases and Maintain Postharvest Quality of Wine Grapes.

In most wine-growing countries of the world the interest for organic viticulture and eco-friendly grape production processes increased significantly in the last decade. Organic viticulture is currently dependent on the availability of Cu and S compounds, but their massive use over time has led to negative effects on environment health. Consequently, the purpose of this study was to evaluate the effectiveness of alternative and sustainable treatments against powdery mildew, gray mold and sour rot under the field conditions on Nero d’Avola and Inzolia Sicilian cultivars. In detail, the efficacy of COS-OGA, composed by a complex of oligochitosans and oligopectates, and its effects in combination with arbuscular mycorrhizal fungi (AMF) were evaluated to reduce airborne disease infections of grape. COS-OGA combined with AMF induced a significant reduction in powdery mildew severity both on Nero d’Avola and Inzolia with a mean percentage decrease of about 15% and 33%, respectively. Moreover, COS-OGA alone and combined with AMF gave a good protection against gray mold and sour rot with results similar to the Cu–S complex (performance in disease reduction ranging from 65 to 100%) on tested cultivars. Similarly, the COS-OGA and AMF integration provided good performances in enhancing average yield and did not negatively impact quality and microbial communities of wine grape. Overall, COS-OGA alone and in combination could be proposed as a valid and safer option for the sustainable management of the main grapevine pathogens in organic agroecosystems.

Trichoderma species isolated from grapevine with tolerance towards common copper fungicides used in viticulture for plant protection.

Copper-containing fungicides are applied broadly in organic viticulture against downy mildew caused by Plasmopara viticola. Although long-term application of copper-based fungicides is associated with ecotoxic effects on the environment, their use in viticulture is required until sustainable alternatives are available. Trichoderma spp. might be a promising approach to fungicide reduction while promoting plant growth and development and displaying biocontrol activity. This study aims to examine the tolerance and compatibility of Trichoderma spp. to copper fungicides. This work contributes to the development of a spray application consisting of a copper-tolerant Trichoderma sp. combined with a downscaled copper fungicide rate against P. viticola. Trichoderma spp. isolated from grapevine wood in vineyards were identified and used for tolerance screening in various concentrations of copper fungicides. Copper hydroxide was identified as being highly compatible with Trichoderma. Two Trichoderma candidates, T. koningiopsis and T. harzianum, showed high copper tolerance in mycelial growth and germination tests, and were adapted to 2.85 g Cu L-1 of the selected fungicide. Microscopic investigations showed the attachment of copper compounds to fungal cell walls and copper uptake within the cytoplasm. In the case of high tolerance, large-scale copper uptake was prevented. Our findings identified two highly copper-tolerant Trichoderma isolates with natural adaptation to the vineyard ecosystem, which could be further tested as biostimulants and biocontrol agents, combined with a reduced fungicide rate for sustainable plant protection. © 2022 Society of Chemical Industry.

Positive effects of organic viticulture on carabid beetles depend on landscape and local habitat conditions

AbstractAgricultural intensification is a major cause of biodiversity loss. Organic farming may counteract the loss of species, however, knowledge about its benefits for perennial agroecosystems such as vineyards is incomplete. We, therefore, analysed the effects of organic viticulture on carabid beetles, a frequently used indicator group in agroecology. We investigated organic and conventional vineyards in two different landscapes (‘simple’ vs. ‘complex’) in SW Germany using a paired design. As a key result we found positive effects of organic viticulture on carabid diversity only in the simple landscape while such an effect was not obvious in the more complex landscape. Moreover, the species composition was differently influenced by organic management between the two landscapes indicating context‐dependent responses of carabid species towards the farming practice. We conclude that positive effects of organic viticulture on carabid beetle diversity differ with landscape context and depend on local habitat conditions such as slope inclination and the inter‐row vegetation. Our results therefore indicate that organic viticulture benefits are not only highly variable among taxonomic groups, but can have even varying effects within one insect family.

Analysis of the varietal composition of vineyards in Ukraine and the potential for growing new varieties

The object of current research is the varietal composition of industrial vineyards in Ukraine. One of the most problematic aspects is the assortment of table grapes, which is represented by a limited number of varieties, especially in industrial viticulture. That is why the local market is saturated with imported table grapes. Viticulturists have been creating Ukrainian grape varieties since the middle of the last century. 150 promising varieties and hybrid forms were bred. They combine high productivity and product quality with high rates of adaptability to the «risky» growing conditions of the Northern Black Sea coast. Many years of research confirmed a high level of pathogen, drought and frost resistance, winter hardiness, as well as a high level of quality traits. The inclusion of modern Ukrainian varieties in the regional assortments, especially with the usage of intensive cultivation, will ensure the development of sustainable viticulture. Due to genetically determined pathogen resistance, a significant reduction in pesticide load is possible, which in the future will ensure the transition to adaptive, and later to organic viticulture. The results of the analysis of the composition and structure of the assortment of grapes in Ukraine are obtained and the new varieties with a high level and stability of productivity and product quality for improving the assortment are suggested. This provides the opportunity to increase profitability by 250–350 % for table varieties, due to high productivity, reducing pesticide load, and increasing the price of product due to the visual appearance and high taste properties. Common varieties require 9–12 pesticide treatments, the usage of additional stimulants such as gibberellins, and other elements of production intensification to obtain the marketable product. New wine varieties also show significant economic potential, as they have higher winter hardiness, pathogen resistance, and exclusive wine characteristics.

Evaluation of plant protection efficacy in field conditions and side effects of Lysobacter capsici AZ78, a biocontrol agent of Plasmopara viticola

ABSTRACT Downy mildew, caused by Plasmopara viticola, is a highly significant grapevine disease causing severe yield losses and affecting wine quality. Disease control mainly relies on use of copper and synthetic fungicides. Today there is a growing interest in developing microbial biopesticides for downy mildew control in integrated and organic viticulture. Here, the bacterial biocontrol agent Lysobacter capsici AZ78 (AZ78) was tested following a holistic approach including in planta efficacy test (large-scale trial) combined with bioassays aiming to assess potential adverse effects on non-target organisms: beneficial arthropods (Aphidius rhopalosiphi and Typhlodromus pyri), the crustacean Daphnia magna, the algae Selenastrum capricornutum and soil organisms [earthworm Eisenia (Ei.) fetida and worm Enchytraeid (En.) albidus]. Moreover, side effects of AZ78 treatments on grape quality and wine-making process were assessed. The results showed that AZ78 was equally effective to reference fungicide (Kocide®2000) in controlling downy mildew on leaves and bunches. AZ78 had no significant effect on the mortality of the indicator arthropod species at a Limit test Rate, which was equal to four times the recommended field rate. Additionally, no significant effects (mortality, growth rate or reproduction) were observed on D. magna, Ei. albidus, En. fetida and S. capricornutum, indicating AZ78 low toxicity on non-target organisms. Likewise, the yeast population dynamics in fermenting musts was not affected, without compromising the fermentation processes and wine quality. Overall, this study provides new insights into the characterisation of the biocontrol agent AZ78 showing that this bacterium has the potential to be further developed as a commercial biopesticide.

Inter-row floor management is a powerful factor for optimising vine balance in a non-irrigated organic Barbera vineyard in northern Italy

Floor management in organic viticulture plays a key role as weed suppression and soil health must be warranted through practices that minimise the recourse to extensive tillage and herbicides, while any resident vegetation or sown cover crop should exert moderate competition for water and nutrients towards the consociated vines. Lack of knowledge exists about the fraction of soil cover crop coverage (Scc) which might represent the best compromise between the above needs. A four-year study (2017–2020) was conducted in an organically managed cv. Barbera/420 A vineyard in the North-West of Italy, comparing five floor management treatments each having light tillage as the practice chosen to control the under trellis weed growth. Inter-row treatments were permanent grass (PG), tillage (T), alternate tillage and permanent grass every second mid-row (AGT), a variant of this last treatment, where the tilled mid-row was used for growing a temporary winter cover crop terminated in spring (AGC) and temporary grass (TG) where grass was disked post-harvest (mid-October) until natural growth resumption in late winter (mid-February). An assessment was made for soil profile and physicochemical composition, floristic analyses performed in T, PG, and TG treatments, vegetative growth, yield components, grape maturity at harvest, single leaf gas exchange as well as midday and pre-dawn leaf water potentials. While overall scant, mostly season-related differences were found for leaf function and water status, soil management heavily impacted vine performance. Year-round soil cover crop coverage (Scc) regressed towards total pruning weight/vine and yield/vine showed high linear correlation (R2 = 0.93) for pruning weight/vine (to be reduced by 38% at 75% Scc vs. 0% Scc of the T treatment), whereas yield/vine was quite poorly correlated (R2 = 0.21) showing a 15% decrease in PG vs. T. Regressing Scc vs total soluble solids (TSS), titratable acidity (TA), total anthocyanins and phenolics concentration disclosed mild linear correlation (R2 = 0.52) for the two technology ripening parameters and a much tighter fit for colour and phenolics (R2 = 0.79 and 0.90, respectively). AGT had an intermediate behaviour between its two extremes (i.e. T and PG) without assuring any significant marginal gain. Conversely, modulating PG into TG through a temporary removal of the resident vegetation in the fall and AGT into AGC by growing a winter cover crop terminated in the spring as mulching, gave the highest yield at adequate technological and phenolic ripeness. PG assured maximum grapes total soluble solids and total anthocyanin concentration at harvest; however, due to its low vigour, several shortcomings also followed, such as low yeast available nitrogen and malic acid concentration, as well as a tendency to accumulate high amounts of flavonols. Our work led to the conclusion that AGC and TG treatments are quite valuable choices under the specific environment for successful soil management in organic vineyards.

Organic viticulture enhanced the activity of native entomopathogenic nematodes in DOCa Rioja soils (North of Spain)

Vineyards and their associated socio-economic activities are relevant sectors worldwide. Still, this agroecosystem is one of the most intensely managed crops and erosion-prone land areas. The conventional viticulture practices to control pests, diseases, and weeds, like tillage and agrochemical applications, accelerate the loss of soil biodiversity and compromise the presence of beneficial soil organisms such as the entomopathogenic nematodes (EPNs). Such human disturbances in the agroecosystems can strongly affect abiotic (e.g., soil texture and properties) and biotic factors (natural enemies and potential competitors) that modulate the EPN activity as biological control agents. For the first time in viticulture, this study aimed to investigate the impact of differentiating management on the EPN community and associated soil organisms and if their assemblage will provide indicators of better practices for sustainable farming. We hypothesized that organic pest management and alternative strategies to tillage might enhance the abundance and activity of the native EPN community in vineyard soils. In autumn 2019, we collected two composite soil samples from 80 vineyards distributed across the Guaranteed Designation of Origin (denominated DOCa) Rioja region. The sites belonged to one category of each of the two factors: pest management (integrated vs. organic, 40 plots each) and soil managing (tillage vs. cover cropping, 48 and 32 vineyards, respectively). Isolated through sucrose-gradient centrifugation and employing species-specific primers/probe qPCR sets, we investigated the presence of ten EPN species and associated soil organisms: four free-living nematodes (FLNs), six nematophagous fungi (NF), and two ectoparasitic bacteria (EcPB). Besides, we estimated the EPN activity using the traditional insect-bait method. We included in the analysis twenty soil variables to characterize the evaluated treatments and assess their impact on soil organism distribution. Our results provide evidence on the support of organic viticulture to beneficial soil organisms, notably the activity of native EPNs. We also reported a higher abundance of S. feltiae (the predominant steinernematid species in Europe) and FLNs for organic farming than IMP, while the presence of NF and EcPB resulted in unaffected. Contrarily, the soil management practices considered did not differ in their impact on EPNs or their natural enemies/competitors, even if contrasted for several soil properties. Future research may expand the screened soil-dwelling species using novel molecular technics to unravel their complex interactions and determine the best farming practices to preserve soil health.