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

A 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 skeleton or lime content, and poor drainage. Nutrient unbalance or toxicity, and low cation exchange capacity, occurred sporadically. Since physical and hydrological limitations are hardly modifiable, the study underlines the difficulties to restore the fertility of degraded soils, and suggests caution in planning new vineyards

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

Local topographic and edaphic factors largely predict shrub encroachment in Mediterranean drylands

Shrub encroachment influences several ecosystem services in drylands worldwide. Yet, commonly used strategies to reduce encroachment show a low medium-term success, calling for a better understanding of its causes. Previous works identified multiple drivers responsible for this phenomenon, including anthropogenic and environmental causes. However, the relative effect of climate, topography and edaphic factors on shrub encroachment is not fully understood nor has been properly quantified in Mediterranean Basin drylands. Also, understanding how these drivers lead to changes in plant communities' functional traits associated to shrub encroachment is crucial, considering traits influence ecosystem processes and associated ecosystem services. Here, we studied the understory of a Mediterranean dryland ecosystem composed of savanna-like Holm-oak woodlands, along a regional climatic gradient. We specifically assessed (i) how climatic, topographic and edaphic factors influence understory relative shrub cover (RSC) and (ii) their direct and indirect effects (via RSC) on plant functional traits. We studied the mean and diversity of 12 functional traits related to plant regeneration, establishment, and dispersal, at the community-level. We found that, under similar low-intensity land use, topographic and edaphic factors, namely slope variations and soil C:N ratio, were the most important predictors of shrub encroachment, determining communities' functional characteristics. Climate, namely summer precipitation, had a much lesser influence. Our model explained 52% of the variation in relative shrub cover. Climate had a stronger effect on a set of functional traits weakly involved in shrub encroachment, related to flowering and dispersal strategies. We show that shrub encroachment is largely predicted by topo-edaphic factors in Mediterranean drylands subject to conventional low-intensity land use. Hence, management strategies to reduce encroachment need to take these drivers into account for efficient forecasting and higher cost-effectiveness. Our results suggest that climate change might not greatly impact shrub encroachment in the Mediterranean Basin, but may affect functional structure and reduce functional diversity of plant communities, thus affecting ecosystem functioning.info:eu-repo/semantics/publishedVersio

Ecological restoration across the Mediterranean Basin as viewed by practitioners

Restoration efforts in the Mediterranean Basin have been changing from a silvicultural to an ecological restoration approach. Yet, to what extent the projects are guided by ecological restoration principles remains largely unknown. To analyse this issue, we built an on-line survey addressed to restoration practitioners. We analysed 36 restoration projects, mostly from drylands (86%). The projects used mainly soil from local sources. The need to comply with legislation was more important as a restoration motive for European Union (EU) than for non-EU countries, while public opinion and health had a greater importance in the latter. Non-EU countries relied more on non-native plant species than EU countries, thus deviating from ecological restoration guidelines. Nursery-grown plants used were mostly of local or regional provenance, whilst seeds were mostly of national provenance. Unexpected restoration results (e.g. inadequate biodiversity) were reported for 50% of the projects and restoration success was never evaluated in 22%. Long term evaluation (> 6 years) was only performed in 31% of cases, and based primarily on plant diversity and cover. The use of non-native species and species of exogenous provenances may: i) entail the loss of local genetic and functional trait diversity, critical to cope with drought, particularly under the predicted climate change scenarios, and ii) lead to unexpected competition with native species and/or negatively impact local biotic interactions. Absent or inappropriate monitoring may prevent the understanding of restoration trajectories, precluding adaptive management strategies, often crucial to create functional ecosystems able to provide ecosystem services. The overview of ecological restoration projects in the Mediterranean Basin revealed high variability among practices and highlighted the need for improved scientific assistance and information exchange, greater use of native species of local provenance, and more long-term monitoring and evaluation, including functional and ecosystem services' indicators, to improve and spread the practice of ecological restoration

Salt-affected soils: field-scale strategies for prevention, mitigation, and adaptation to salt accumulation

The area of salt-affected soils is increasing globally, mainly due to land use and management malpractices, which can threaten soil health and the sustainability of farms. Climate change is likely to increase the prevalence of salt-affected soils in many agricultural areas due to increased aridity and, in coastal areas, due to the increase in sea water level. The causes and processes that develop salt-affected soils are diverse and can result in soil salinity, sodicity, alkalinity, or a combination of these conditions. There is a need to continuously update strategies to tackle salt-affected soils, finding solutions tailored at different scales. This work presents a review of the current knowledge related to salt-affected soils and identifies specific strategies and related case studies for the prevention, mitigation, and adaptation to salt accumulation in soils at the field scale while addressing their limitations, advantages, research needs, and innovation potential. The presented case studies show that adequate irrigation management and drainage can be used as a preventive measure to counter salt accumulation in soils. Phyto and bioremediation can be effective practices for the mitigation of soil sodicity. Leaching and drainage can be effective measures for mitigation of soil salinity. Crop rotation and management of soil organic matter can be used as adaptative measures that improve plant tolerance to salt-affected soils, while a newer approach, microbial management, shows innovation potential as an adaptative measure

A multivariate approach for the study of environmental drivers of wine economic structure

Vitivinicultural "terroir" is a concept referring to an area in which the collective knowledge of the interactions between environment and vitivinicultural practices develops, providing distinctive characteristics to the products. The effect of the environmental components over the terroir wines has been already widely demonstrated, but their possible effect on the overall system of production and organization of the viticultural farms and wine industry, called "wine economic structure" in this study (WES), is still unknown. Thus the research hypothesis of this work was that there are environmental drivers influencing WES.The investigation was carried out at the national scale, taking Italy as study area, the biggest wine producer of the world. We used viticultural territories singled out at 1:500,000 reference scale, called viticultural Macroareas, which grouped Denomination of Origin areas with respect of geographic proximity, environmental features, viticultural affinity, and wine tradition. The characterization of WES was based on the official data reported in the wine production declarations related to the year 2008. Statistics were taken into account about general quantitative variables of wine farms, presence of associative forms, degree of vertical integration of wineries, quality orientation of wine producers, and acreage of vineyard. Environmental variables related to climate, soil, and vegetation vigour were selected for their direct influence on the vine growing. A second set of variables was chosen to express the effect of land topography on viticultural management. A third one was intended to discover the possible relationships between WESs and land qualities, such as the indexes of sensitivity to desertification, the soil resistance to water erosion, and land vulnerability. A multivariate approach was carried out to elaborate the many studied variables and their interactions. Nonparametric statistics were also used, to overcome the necessity of normal distributions. A PCA was carried out separately for the environmental and economic data, to reduce the dimension of datasets. The new economic and environmental synthetic descriptors were submitted to three multivariate analyses: (i) the correlation between economic and environmental descriptors, through the non-parametric Spearman test; (ii) a cluster analysis to group the Macroareas in few homogeneous WESs; (iii) a discriminant analysis of economic clusters and environmental factors, to highlight the environmental drivers of WESs. The results highlighted that in some Macroareas there is a direct correlation between high quality wine production and presence of low available soil water, due to both soil and climatic limitations. In other Macroareas, the limited quantity and quality of wine yield showed a significant relationship with the presence of rough morphologies and high environmental variability. Similarly, heterogeneous soil and morphological conditions fitted well with both the absence of well-defined economic structures, and a relatively lower quality production. The cluster analysis identified six main WESs for the whole country. Climatic, pedoclimatic, morphological mean conditions and topographic heterogeneity of Macroareas had the most important discriminant power over the clusters. The result of this multivariate analyses proved that the different WESs of a country are significantly influenced by specific landscape characteristics. Therefore, landscape care has a strategic role also on the development of the wine industry

THE POTENTIAL OF γ-RAY SPECTROSCOPY FOR SOIL PROXIMAL SURVEY IN CLAYEY SOILS

Gamma-ray spectroscopy surveys the intensity and distribution of γ-rays emitted from radionuclides of soils and bedrocks. The most important radionuclides of soils and rocks are: 40K, 232Th, 238U and 137Cs, the latter due to Chernobyl burst or radioactive pollution. Distribution and quantity of these radionuclides into the soil is strictly linked to parent material mineralogy and soil cation exchange capacity. The aim of this work is to show the makings of γ-ray spectroscopy proximal survey within experimental fields with clayey soils in western Sicily.The γ-ray spectrometer used for the fieldwork was “The Mole”, made by “The Soil Company”, “Medusa system” and the University of Groningen, from The Netherlands. During the survey of eight experimental fields, 55 soil samples were collected for laboratory analysis of particle size distribution, calcium carbonate, organic carbon and total nitrogen content. The results of the work showed the statistical correlations between soil features and γ-ray data.

Scale effect of viticultural zoning under three contrasting vintages in Chianti Classico area (Tuscany, Italy)

The present study, performed in one of the largest farm of “Chianti Classico” wine district (Tuscany, Italy), focused on the effect of terroir on the peculiarities of the wine at two different scale of zoning. At a broader scale, the experimental vineyards were selected on the basis of lithology, soil type, morphology and climate and these were called macro-terroir (MT). Each vineyard was subdivided into a couple of homogeneous zones (Unité Terroir de Base, UTB), differentiated on the basis of soil proximal sensing, and then, high-detailed soil mapping. The study was conducted during three consecutive vintages (2012, '13 and '14), on four different vineyards MT, which are representative of the Chianti Classico wine district. Grape harvest, wine-making and six-month ageing were carried out separately for each UTB, using the same methodology. This study demonstrates that characteristics of geopedological landscapes can be used for a wine district zoning, while a more detailed soil mapping, leading to UTB identification, is needed to highlight some wine peculiarities