Displays

The Rheingau is one of the 13 designated German wine-growing regions and produces the highest proportion of Riesling in Germany. The effects of climate change on air temperature and precipitation can already be seen in phenological observations. The result is an earlier beginning of the budding, flowering and maturing dates. If the date of the beginning of the wine harvest for Riesling in the period 1961-1990 was on October 17 on average, the time in the period 1981-2010 shifted five days to the beginning of the month to October 12. In 2019, the harvest yield was significantly lower than the average of the past ten wine harvests. A consequence of increasing drought and heat in summer, more sunburn damage, but also increasingly late frosts and hailstorms. An evaluation of climatic variables for the near future (2050) relevant to viticulture performed for the individual phenological phases indicated critical changes. An increasing probability of the occurrence of tropical nights (minimum air temperature ≥ 20°C) which would potentially endanger the character of the Riesling and an increased probability of humid conditions during maturation, with the danger of higher pest load is to be expected. Higher, increasing evaporation rates will further reduce the availability of soil water in the growing and especially in the maturing phase. A systematic and regional-specific adaptation strategy for the Rheingau is still lacking. In addition, viticulture produces monoculture agro-ecosystem and causes specific environmentally problems, like soil erosion, loss of biodiversity and nitrate leaching relating to surface and groundwater eutrophication. The KliA-Net project launched in the middle of 2019 to address these problems together with the effects of climate change and to find sustainable, nature-based and landscape-integrative solutions. The aim of the project is to establish local and, above all, inter-communal cooperation and to develop it into joint action for adaptation to climate change. The resulting impulses lead to measures to reduce climate damage under the premise of climate protection, sustainable management and the best possible provision of ecosystem services. We will present the overall theoretical framework and the integrated approach to demonstrate that the concept of Terroir reflects the interactions between people and nature. Here, the concept of Vinecology was adapted, as the integration of ecological and viticultural principles and practices; it contextualizes sustainable land management within the specific agricultural sector and serves as an entry point to biodiversity conservation in an economically and biologically important biome integrated in its adjacent landscape. Concrete measures for climate adaptation in viticulture compiled in a catalogue, which is divided into 5 areas of action: viticulture, soil protection, water, biodiversity and landscape. These represent the different vinecological scales (landscape, vineyard, plant). This catalogue forms the basis for the transfer of knowledge between science, winegrowers, communal politics, administration and NGOs. Furthermore, we also contextualize related ecosystem services to indicate benefits resulting from a concrete measure. We hypothesize, that this is a way to harmonize objectives in nature conservation, soil and water protection and sustainable economic development.

How to cite: Reiss, M., Bernard, B., and Jedicke, E.: Climate Change Resilience in Viticulture: Knowledge transfer and ecosystem services of adaptation strategies, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-37, https://doi.org/10.5194/egusphere-egu2020-37, 2020.

Weather and climatic conditions have a strong implication on wine production and quality. High-Resolution agroclimatic zoning over 50 protected denominations of origin (DOs) in Portugal is carried out using two agroclimatic indices commonly applied in viticultural zoning (dryness and Huglin indices). For this purpose, a high-resolution dataset of climate data over Portugal and for 1981–2015 (baseline) is used. Furthermore, climate change projections are assessed based on two anthropogenic forcing scenarios (RCP4.5 and RCP8.5), retrieved from a 5-member climate model ensemble over two future periods (medium-range: 2041–2070, and long-range: 2071–2100). An optimized compound index was isolated from a principal component analysis applied to the time mean spatial patterns of the two selected indices, for baseline and over vineyard cover areas in each region only. The spatial variability of Portuguese DOs is highlighted. For the future periods, and regardless of the scenario, significant changes in the agroclimatic conditions are projected for most of the DOs. In future scenarios, strong upward trends in the growing-season mean temperatures, along with an overall strengthening of dryness are projected. This is particularly noteworthy in south-eastern Portugal and north-eastern Portugal along the upper Douro Valley. Hence, as Portuguese DOs are projected to become much drier than currently, irrigation or the selection of new varieties are likely adaptation measures to maintain the viability and sustainability of regional viticulture in future decades. New research methods and decision support tools should be applied to assist stakeholders in developing more climate change-resilient viticulture. The Clim4Vitis project (Climate change impact mitigation for European viticulture: knowledge transfer for an integrated approach, WIDESPREAD-05-2017 Twinning, European Union’s Horizon 2020 research and innovation programme, under grant agreement nº 810176) has been very active in promoting capacity building activities and knowledge transfer to the European winemaking sector.

How to cite: Santos, J. A., Santos, M., Fraga, H., and Fonseca, A.: Agroclimatic zoning of wine denominations of origin in Portugal: current and future conditions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2347, https://doi.org/10.5194/egusphere-egu2020-2347, 2020.

In the Mediterranean area, the expected increase in temperature coupled with the decrease in rainfall, as well as the increase in the frequency of extreme events (heatwaves and drought, IPCC, 2019), will severely affect the survival of current vineyard areas. Cultivar thermal requirement and soil water availability could be not satisfied, leading to a limitation in yield and berry quality also due to constraints in the achievement of optimal grape maturity.

In this context, the understanding of how the spatial viticultural suitability will change under climate change is of primary interest in order to identify the best adaptation strategies to guarantee the resilience of current viticultural areas. Moreover, the improvement of knowledge of climate, soil, and their interaction for each specific cultivar will be fundamental because the terroir system is based on this interaction able to influence the plant status (e.g., water).

In this study, different pedo-climatic conditions (past, present, and future) in three Italian sites at different latitudes (from center to southern), were compared for two red varieties of grapevine: Aglianico (indigenous cv) and Cabernet Sauvignon (international cv).

Grapevine adaptation to future climate in each experimental farm in Campania, Molise, and Sicily Italian regions has been realized through the use of bioclimatic indexes (e.g., Amerine & Winkler for Aglianico 2110 GDD). The climatic evaluation was performed using Regional Climate Model COSMO-CLM at high-resolution (8km x 8km) climate projections RCP4.5 and RCP 8.5 (2010-2100) and Reference Climate (RC, 1971-2005).

Results have shown how climate change will affect the cultivation of Aglianico and Cabernet Sauvignon, considering both the climate and bioclimatic needs of cultivars themselves in the current viticultural areas.

Finally, coupled with the climatic evaluation, a pedological survey to characterize the soils, and the analysis of satellite images (Sentinel2 ) coupled with stemwood anatomical analysis has been performed to reconstruct the past eco-physiological behavior.

How to cite: Monaco, E., De Mascellis, R., Barbato, G., Mercogliano, P., Buonanno, M., Brook, A., De Micco, V., and Bonfante, A.: Pedoclimatic comparison of three viticultural areas of Italy devoted to high-quality Aglianico and Cabernet Sauvignon production, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7384, https://doi.org/10.5194/egusphere-egu2020-7384, 2020.

Vitis vinifera L. cultivar “Cannonau” (Magnoliopsida Vitaceae) has been grown for years in the Italian regions to produce a fine wine, with Controlled Designation of Origin (DOC) and Denomination of Controlled and Guaranteed Origin, (DOCG). The International Organization of Vine and Wine (OIV) defined the “terroir” as “a concept which refers to a specific area in which the interactions between the physical and biological environment and applied vitivinicultural practices develops. Whereas, from a geological point of view, the terroir has been defined as the geochemistry of soil, surface and ground water. Recent studies, regarding vitis vinifera, based on geochemical characterization have clearly shown the connection among geological origin, vineyard soil and grape berries. Another way to trace geographical origin can be through the identification of Rare Earth Elements (REEs) in the soil-plant system. However, the study of REEs is also important to define the petrological characterization and the relations between soil and plants.

We evaluated the relationship among the concentrations of rare earth elements (REE) in soil and in “Cannonau” grape berries in vineyards belonging to two different vineyards located in the valleys Pardu and Pelau in Sardinia (Italy) and one in Susegana in the Veneto Region (Northern Italy). The concentration of REE in samples of soil and juice or solid residues of grape berries was determined by inductively coupled plasma mass spectrometry (ICP-MS) and the data were elaborated with multivariate statistics (Linear Discrimination Analysis).The concentration of REEs in soil and grape berry samples allowed an identification of each locality examined . Moreover, the geochemical and statistical analyses allowed to discriminate the vineyard soils and grape berries according to geo-lithological characteristics of each area and to identify possible geochemical markers for the cultivar “Cannonau” .These markers, suitable as terroir fingerprintings, may be useful to avoid fraudulent use of the denomination label and falsification of the Made in Italy trademark.

How to cite: Pepi, S. and Medoro, V. and the Giulia Piroddi, Elena Marrocchino, Carmela Vaccaro: Study of the distribution of Rare Earth Elements in soil and in Vitis Vinifera L.cv Cannonau in two different regions , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4053, https://doi.org/10.5194/egusphere-egu2020-4053, 2020.

Rare Earth Elements (REE) have been employed to stimulate the plant growth in national and international strategies while their role still remains controversial as the process involved in soil-plant system is not completely understood yet.  

In this study we have investigated the effect of REE amount in the substrate during the Vitis vinifera L growth analysing the REE distribution in the different part of the plants. Experiments were carried out over 1 year using two different substrates: one with a "natural" substrate (blank experiments) and another using the same substrate artificially enriched by an equimolar solution of REE (spiked experiments).

We found that both plant mass and amount of REE in leaves are both not influenced by the substrate enrichment. However, roots are by 1 order of magnitude enriched in REE for the 3 orders of magnitude enriched substrate of growth. This indicates that Vitis vinifera L. does not significantly transfer REE into the aerial parts during growth while identify roots as the plant critical parts responsible for the filtering of the environmental stress.  Plotting the REE normalized distribution for every element, the different experimental conditions can be significantly discriminated: under spiked substrate conditions, REE normalised distribution shows a ‘zig zag’ pattern in both leaves and roots. We propose that the REE normalised distribution pattern measured in the different plant parts (leaves and roots) can be used to discriminates the conditions of substrate characteristics during the vitis vinifera growth. Acting as natural tracers, the REE normalised distribution could be potentially used as tool tracing the substrate origin of the Vitis vinifera plant. 

How to cite: Barbera, M., Zuddas, P., and Saiano, F.: The distribution pattern of Rare Earth Elements (REE) in Vitis vinifera L. discriminates the substrate of growth ?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5770, https://doi.org/10.5194/egusphere-egu2020-5770, 2020.

Copper (Cu) and zinc (Zn) are important micronutrients for vine plants; however, the long-term use of Cu-fungicides and micronutrient fertilizers can lead to their accumulation in the topsoil of vineyards. Water erosion on sloping vineyards transports sediments downslope, a processus that may redistribute micronutrients in the topsoils. Our study aims at assessing the rate of enrichment in Cu and Zn of vineyard topsoils compared to the geochemical background and their downhill transport during rainfall events attached to sediments.

The study was conducted in 2019 in a 1,8 ha sloping vineyard at Tokaj (mean slope: 8°) and a 0.4 ha plot near Tállya (mean slope: 18°), both in the historical vinegrowing region of Tokaj-Hegyalja (in northern Hungary). The vineyards at Tokaj have been converted to organic farming, where Cu-based fungicides are repeatedly used in a typical dose of 4 kg/ha/year, supplemented with fertilizers containing micronutrients. The soil samples from the top layers (0-10 cm and 10-20 cm) have been collected using a hand auger from the two vineyards and from local forested sites, the latter accounting for the local geochemical background. Additionally, sediment traps have been deployed for collecting eroded sediment samples. The examined soil type is a Regosol at Tokaj with sandy loam texture, while the Cambisol at Tállya displays slightly heavier soil texture (sandy loam/loam). The soils are characterized by a slightly acidic pH(d.w.) of 6.36±0.27 at Tállya and a moderately alkaline pH(d.w.) of 8.03±0.04 at Tokaj. The differing pH is due to the soil forming parent rocks, that are loess at Tokaj and rhyolite at Tállya. The topsoils (0-20 cm) bear a low to medium organic matter (OM) content (1.5±0.5% OM at Tállya and 1.4±0.2% OM at Tokaj) and a low carbonate content at Tállya (3.1±0.2%), while a low to medium carbonate content at Tokaj (4.4±1.5%).

The micronutrient (Cu, Zn) concentrations have been determined by an inductively coupled plasma-optical emission spectrometer, following microwave-assisted digestion of powdered soil samples in aqua regia (hydrochloric acid:nitric acid = 3:1). At Tállya, our results show a considerable Cu enrichment and a slight Zn enrichment in the topsoil (mean±se: 127±37 mg/kg Cu, 47±4 mg/kg Zn) due to the repeated use of pesticides and fertilizers, compared to a local forested soil displaying 5 mg/kg Cu and 28 mg/kg Zn. The lower Cu enrichment in the vineyard topsoil at Tokaj (49±14 mg/kg in vineyards, 17 mg/kg at the local forested site) is probably due to the more recent plantation of grapevines. The soil-bound Zn at Tokaj also displayed to some degree higher concentrations in the top 20 cm layers in vineyards (64±6 mg/kg) as to the forest soil, exhibiting 41±3 mg/kg Zn. At both sites, eroded sediments tend to display higher Cu and Zn concentrations relative to the vineyard topsoils with mean enrichment factors (sediments/topsoil) of 4.2 (Cu) and 1.4 (Zn). Additionally, we evidenced that soil erosion significantly affects the topsoil Cu concentrations at Tokaj, as higher Cu concentrations have been found downslope, where the eroded sediments accumulate, compared to the erosion bases upstream.

How to cite: Babcsányi, I., Thi Ha Pham, N., Balling, P., Tobak, Z., and Farsang, A.: Accumulation of micronutrients (Cu, Zn) in vineyard soils and transport via soil erosion, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21339, https://doi.org/10.5194/egusphere-egu2020-21339, 2020.

The northern loess-covered part of the Gerecse belongs to the Ászár-Neszmély Wine Region, and is highly frequented by soil erosion. One of the largest vinery in the region recognized the problem and already makes efforts to cope with the natural degradation, but the exact measure of soil loss, and thus its cost, is yet unknown. In this project three vineyards were selected in the vicinity of Dunaszentmiklós village. Previous studies identified the most erosion-sensitive locations using satellite images, but to specify the soil erosion between the rows of grape vines, high resolution images were collected with UAV (Unmanned Aerial Vehicle). The images were used to create the digital surface model (DSM) and the orthophoto of the areas by means of photogrammetric analysis. The final resolution in which the soil loss was defined is 10 cm.

Since the summer of 2019 data have been collected in seasonal measurements. We used the USLE (Universal Soil Loss Equation) model [1] to determine the soil loss and its precise location. The focus was on the definition of the C (crop management) and the R (rainfall erosivity) factors because these change from season to season. The effect of the change of land cover as the summer turned into autumn was remarkable from the aspect of soil erosion. A similar change was observed in the weather impact: in this period more rain fell during the summer than in the autumn. According to the USLE model in the study area the rate of the soil loss was twice as high during the summer as in the autumn.

The vinery do its best to prevent soil erosion. One of their effective method is to sow grass among the vines. In this study a hypothetic model was also created to prove the importance of their method in the scale of the erosion. The most significant difference between the results of the model and the reality was observed in the summertime. Based on the hypothetic model the soil loss would be 3.5 times more if they would not take care of sowing grass in the vineyard.

The project was supported by the ÚNKP-19-2 New National Excellence Program of the Ministry for Innovation and Technology (from part of T. Takáts),  the Thematic Excellence Program, Industry and Digitization Subprogram, NRDI Office, project no. ED_18-1-2019-0030 (from part of G. Albert), and the  Hilltop vinery.

Data Sources:

Precipitation data from the OMSZ Hungarian Meteorological Service and the K factor (soil erodibility) from Pásztor et. al. [2] MTA ATK TAKI.

References:

[1] Wischmeier, W. H., & Smith, D. D. (1978). Predicting rainfall erosion losses- a guide to conservation planning. USA: USDA, Science and Education Administration.

[2] Pásztor, L., Waltner, I., Centeri, C., Belényesi, M., & Takács, K. (2016). Soil erosion of Hungary assessed by spatially explicit modelling. Journal of Maps, 1-8.

How to cite: Takáts, T. and Albert, G.: Soil loss monitoring of vineyards in the Gerecse Hills (Hungary), using UAV technology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5156, https://doi.org/10.5194/egusphere-egu2020-5156, 2020.

Sustainable grapevine cultivation and the stable production of high-quality wine is endangered by climate change in many areas of the Mediterranean region. Climate change is expected to induce rising temperatures, changes in precipitation frequency and increasing occurrence of extreme events such as severe and prolonged drought with direct effects on berry production and composition, and consequently wine quality. In this context, the monitoring and dynamic assessment of vine status with an early detection of health decline signs are needed to evaluate and adopt mitigation actions oriented to precision and sustainable agriculture (e.g., irrigation).

Several indicators are reported in literature to evaluate plant health status (e.g., Ref. MAES reports), based on remote sensing, UAV techniques or in situ data collection. With remote sensing technologies, standardized information, over large areas, at low costs and with high temporal coverage, can be acquired, allowing assessment of plant indicators trends in a practical, repetitive and comparative way. However, data processing techniques do not fully reflect the overall physiological status and healthiness of plant systems. On the other hand, in situ morpho-physiological analyses at the single plant level are time-consuming and restricted to a low number of individuals compared to remote sensing or UAV techniques, not always covering the whole variability of the vineyards.

This study aimed to apply an integrated multidisciplinary conceptual approach for vine health assessment, based on a systematic process for a multi-source, multi-scale and multi-temporal synergic interpretation of data with different techniques in order to cover the gaps of the single disciplines. This approach was recently developed and successfully tested on an Aglianico vineyard in Southern Italy and its applicability needs to be tested on other terroirs.

Therefore, in this study, the multidisciplinary approach was calibrated and applied in a hilly environment in southern Italy (La Guardiense farm, Guardia Sanframondi, Benevento, Campania region) on Vitis vinifera L. subsp. vinifera ‘Falanghina’ in order to assess the ability of the system to evaluate the plant status during the various phenological phases. The plant status results obtained from four sites were compared with data collected from different techniques including the monitoring of plant growth and ecophysiology as well as the reconstruction of past eco-physiological behavior through the analysis of tree rings in the stemwood.

The overall results confirmed the applicability of such an approach to achieve a comprehensive assessment of the vine health status considering the continuum soil-plant-atmosphere, thus furnishing information on possible plant responses to expected environmental changes as valuable inputs to manage cultivation factors in various terroirs.

How to cite: Brook, A., Bonfante, A., Damiano, N., Cirillo, C., Battipaglia, G., Erbaggio, A., Buonanno, M., and De Micco, V.: Assessment of Falanghina vine status at different spatial and temporal scales by means of a smart multiple spatial and temporal resolution system, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11481, https://doi.org/10.5194/egusphere-egu2020-11481, 2020.

Soil erosion is affected by rainfall temporal pattern and intensity variability. In vineyards, machines traffic is implemented with particular intensity from late spring to harvest, and it is responsible of soil compaction, that likely affects soil hydraulic properties, runoff, and soil erosion. Additionally, hydraulic and physical properties of soil are highly influenced by vineyards’ inter-rows soil management. The effect of machines traffic on soil compaction, hydrological and erosional processes has been investigated on a sloping vineyards with different inter-row soil managements (tillage and permanent grass cover) in the Alto Monferrato area (Piedmont, NW Italy). During the investigation (November 2016 – October 2018) soil water content, rainfall, runoff, and soil erosion were continuously monitored. Field-saturated hydraulic conductivity (Kfs), soil penetration resistance (PR) and bulk density (BD) were recorded periodically in portions of inter-rows affected and not by the machine traffic. In order to take into account temporal and management variability of soil compaction and hydrological properties, field-monitored data were statistically analysed, in order to identify existing relationships between climate and management variables and soil physical and hydrological variables. Very different yearly precipitation characterized the observed period, leading to higher bulk density and lower infiltration rates were in the wetter year, especially in the tilled vineyard, whereas soil penetration resistance was generally higher in the grassed plot, and in drier conditions. Soil bulk density and penetration resistance in tracked soil of the tilled plot increase, compared to the grassed plot, after only one to three tractor passages following tillage operation, especially in the topsoil (first 10 cm). Soil compaction affects water infiltration, especially in the wet year. In the tilled vineyard, one tractor passage on wet soil after tillage operation dramatically reduced Kfs from over 1000 to near 1 mm h^-1, while with grass cover Kfs remained above the usual rain-intensity values, allowing water to infiltrate the soil. By means of linear and multilinear regression, significant relationships have been found to relate hydraulic conductivity and soil penetration resistance with soil water content, weather variables and a factor that takes into account the number of tractor passages and the elapsed time from last soil disturbance. Lastly, runoff and soil erosion were higher in the tilled plot, even if lower than the long-period average values. Indeed, in the wet year, management with grass cover reduced considerably runoff (-76%) and soil loss (-83%) compared to tillage and, in the dry season.

How to cite: Biddoccu, M., Capello, G., and Cavallo, E.: Effects of tractor traffic on soil compaction, water infiltration and soil erosion in tilled and grassed vineyards, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10352, https://doi.org/10.5194/egusphere-egu2020-10352, 2020.

In the Mediterranean region, climate change is intensifying the need to improve the resource use efficiency of crops (e.g. water use efficiency) and to increase yield, quality and stability of productions, especially in high profitability and vulnerable crops as grapevine. In a climate change scenario, with increasing temperature and frequency of extreme events, such as prolonged periods of drought, the improvement of knowledge about the plasticity of morpho-functional traits in vines, becomes pivotal. Only a deep knowledge of vine responses to environmental constraints can help achieving the correct management of cultivation factors towards sustainability.

The objective of this study is to apply a multidisciplinary approach for monitoring the resource use efficiency and resource allocation during vine development up to wine production. This general objective will be pursued by analysing the complex relationships between parameters in the continuum environment/plant/wine with specific emphasis on the influence of water availability on the vine, grapes, must and finally wine, in order to relate climate, plant water status and oenological characteristics.

The study was conducted in a vineyard of Vitis vinifera L. subsp. vinifera ‘Falanghina’ located in southern Italy (La Guardiense farm, Guardia Sanframondi, Benevento, Campania region).

The vineyard performance was monitored on the basis of several morphological and eco-physiological parameters, measured in the main phenological phases, including: plant architecture, fertility, leaf anatomical traits, photosynthetic efficiency, leaf gas exchanges, nutritional status, berry and must quality. Water use efficiency was estimated through the analysis of anatomical and stable isotope traits (linked with hydraulic and resource efficiency parameters) from tree-ring series and leaf samples. Stable isotopes were also analysed in the must, in order to check the occurrence of an isotopic signature from the plants towards the must.

The approach proved to be promising for achieving a comprehensive understanding on the impact of environmental constraints not only on plant behaviour, but also on the characteristics of the oenological products, furnishing at the same time a promising tool to reconstruct vine status from the isotopic trace in the must.

How to cite: Damiano, N., Cirillo, C., Battipaglia, G., Amitrano, C., Pannico, A., Caputo, R., Arena, C., Erbaggio, A., Cherubini, P., Saurer, M., Bonfante, A., and De Micco, V.: Relationships between vine hydraulics and wine production in Falanghina: morpho-functional and isotopic traceability to evaluate sustainability in a climate change context, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9928, https://doi.org/10.5194/egusphere-egu2020-9928, 2020.

This study aims to assess the impact of the pre-bloom and post-harvest periods on the diversity of metabolically active soil-rhizosphere microbiota in a commercial vineyard in Sant Sadurní d’Anoia, a typical wine producing region (Penedès DO, Catalonia, Spain). Thereby, total genomic DNA and RNA was simultaneously monitored to distinguish total from active bacterial-fungal microbiota, by molecular tools in both periods. The studied organic vineyard had 20 years old plants of the white grape variety of Macabeu and 41B as a rootstock. Soil had last been amended (14 tm/ha of composted cow manure) 5 years before.

The soil was monitored in April 2018 in the pre-bloom period (stages 09 to 12 Eichhorn and Lorenz 1977) and the post-harvest period (October 2018) in 2 different plots of the vineyard: Zone1 (loam texture with permanent cover crop) and Zone 4 (sandy-loam without vegetal cover). Samples soils were obtained at a soil depth of30 cm and 20 cm of distance from a plant (n=4 for each plot and sampling event). Each soil sample was submerged in a DNA/RNA preservative solution at 4⁰C and afterward stored at -20⁰C until the further analysis. In order to quantify and to assess bacterial and fungal diversity (total and active), (RT)qPCR and MiSeq-Illumina analysis (16SrRNA/ITS1rRNA region) were performed.

Results showed that in post-harvest period the bacterial populations were more active in both zones (2 and 5 orders of magnitude in Zone1 and Zone4, respectively) vs. pre-bloom period. Metabolically active fungal population was increased in both plots by 4 orders of magnitude. It is noteworthy to mention that fungal population was present but not active in pre-harvest period. This fact could be explained for the mutualistic microbe interaction and the environmental conditions (soil temperature and soil water content), including grape drop in harvest linked to rainy conditions.

High-throughput sequencing analysis revealed that the microbial diversity was specific for each plot, vine and sampling period. Bacterial population in post-harvest was more diversified but still dominated by Actinobacteria (mainly by Actinomycetales order), Proteobacteria (mainly by Rhizobiales and Pseudomonadales orders). Interestingly, during post-harvest Clostridiales (Firmicutes phylum), present in the pre-bloom period, completely disappeared. Alpha bacterial diversity was higher than fungal one in both plots. Interestingly, the bacterial diversity (H Shannon index) of metabolically active bacteria (cDNA) was higher during post-harvest season compared to April, suggesting more activity and diversity in the former. On the contrary, fungal diversity was smaller and less uniform in both periods. They were predominated by Ascomycota, Basidiomycota and Zygomycota phyla. Noticeably, the relative abundance (RA) of existing fungal population (DNA) in the soil were highly different compared to the RA of active fungal community (cDNA).

In conclusion, simultaneous RNA/DNA-based molecular biology tools could improve the knowledge of metabolically active microbial populations in vineyard soils under different seasons.

Funding: VITIMPAC project (INIA RTA2015-00091-00-00).

How to cite: Biel, C., Guivernau, M., Viñas, M., Aranda, X., and de Herralde, F.: Unraveling metabolically active fungal-bacterial diversity in commercial organic vineyard soils , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18343, https://doi.org/10.5194/egusphere-egu2020-18343, 2020.

Agricultural productivity is subject to various stressors, including abiotic and biotic threats, many of which are exacerbated by a changing climate. The productivity of tree crops, such as almond orchards, is particularly complex. Moreover, the State of California has implemented legislatively mandated nitrogen (N) management strategies of all growers statewide to minimize nitrogen losses to the environment, and almond growers must now apply N in accordance with the estimated yield in early spring. To understand and mitigate these threats requires a collection of multi-layer large data sets, and advanced analytics is also critical to integrate these highly heterogeneous datasets to generate insights about the key constraints on the yields at tree and field scales. Here we used machine learning approaches to predict orchard-level yield and examine the determinants of almond yield variation in California’s almond orchards, based on a unique 10-year dataset of field measurements of light interception, remote sensing metrics, and almond yield, along with meteorological data. We found that overall the maximum almond yield was highly dependent on light interception, e.g., with each one percent increase in light interception resulting in an increase of 57.9 lbs/acre in the potential yield. Light interception was highest for mature sites with higher long term mean spring incoming solar radiation, and lowest for younger orchards and when March maximum temperature was lower than 19 ^oC. However, at any given level of light interception, actual yield often falls significantly below full yield potential, driven mostly by tree age, temperature profiles in June and winter, and summer maximum vapor pressure deficit (VPDmax). The full random forest model was found to explain 82% (±1%) of yield variation, with a RMSE of 480±9 lbs/acre. When excluding light interception from the predictors, overall orchard characteristics (such as age, location and tree density) and key meteorological variables could still explain 78% of yield variation. The model analysis also showed that warmer winter conditions often limited mature orchards from reaching maximum yield potential and higher summer VPDmax  significantly limited the yield. Our findings through the machine learning approach improved our understanding of the complex interaction between climate, canopy light interception, and almond nut production. The demonstrated relatively robust predictability of almond yield, driven by “big data”, also provides quantitative information and guidance to make informed orchard nutrient management decisions, allocate resources, determine almond price targets, and improve market planning.

How to cite: Jin, Y., Chen, B., Lampinen, B., and Brown, P.: Yield Determinants and Prediction for California’s Almond Orchards Based on Machine Learning Analytics, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10687, https://doi.org/10.5194/egusphere-egu2020-10687, 2020.

Site-specific agricultural management relies on identifying within-field spatial variability and is being used for variable rate input of resources. Precision agricultural management commonly attempts to integrate multiple datasets to determine management zones (MZs), homogenous units within the field, based on spatial characteristics of environmental and crop properties (i.e., terrain, soil, vegetation conditions). This study aims to develop a novel statistical multivariate spatial clustering approach to determine MZs for precision nitrogen fertilization in a citrus orchard along the growing season. Five variables were used to characterize spatial variability (i.e., N spectral index, crop water stress index (CWSI), tree height, elevation, and slope) within four plots based on a monthly thermal and multispectral high-resolution imagery acquired from an unmanned aerial vehicle (UAV). The UAV data was tested against leaf N samplings based on samples taken from 48 trees within the four craters plots, which were selected based on a stratified random design (SRD) model. A Support Vector Machines-Regression (SVM-R) model was applied to develop a prediction N spectral index for canopy N levels. The clustering model included the following components — spatial representation of the data based on Getis Ord Gi*. Then variable weights were assigned based on their relative contribution to principal component analysis. Fuzzy C-means algorithm was applied to the weighted spatial representation and was found to generate spatially continuous and homogeneous MZs with similar numbers of trees. In addition, we analyzed the temporal dynamics in the MZs and clustering patterns throughout the year, using information based on the monthly UAV imagery. Management of the sub-units, or plots, using spatial representation rather than the measured values, is suggested as a more suitable platform for agricultural practices. Future development of fertilization applications for individual trees will require adjusting the statistical approach to support tree-specific management. The proposed model composite is flexible and may be composed of different models and/or variables for developing optimal MZ delineation for specific plots.

How to cite: Paz-Kagan, T., Termin, D., Linker, R., Raveh, E., Ohana, N., and Baram, S.: Site Specific Nitrogen Management in Citrus Orchard to Minimize Nitrogen Pollution, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10572, https://doi.org/10.5194/egusphere-egu2020-10572, 2020.