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Background Apples have a leading role in the Italian fruit sector, and high-quality apples, including the Golden Delicious variety, are cultivated mainly in the Northern mountain districts. In the present study, Golden Delicious apples from PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) cultivation districts were characterized according to their Sr isotope composition and compared with apples from other Northern Italian districts. Results Apples collected in two consecutive years (2017 and 2018) confirmed the low annual variability of the 87 Sr/86 Sr ratio. The isotope ratio of apples was highly correlated with that of the soil extracts of the respective orchards. Statistical differences were highlighted between cultivation districts. However, because similar geological features characterized some areas, their ratios overlapped and a complete separation of the districts was not possible. Conclusion The 87 Sr/86 Sr ratio is an excellent marker for studies of food traceability because it retains the information about the place of origin. However, its strength is limited when comparing products from cultivation areas sharing similar geological features. In the perspective of geographical traceability, a multichemical characterization can overcome the limits of single-parameter approach. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The protection and promotion of agricultural niche products can be supported by the application of analytical techniques able to link food to its territory. This study aimed at exploring the possibility to discriminate between cereal samples from South Tyrol (Italy) and the neighboring regions (Trentino, East Tyrol, and North Tyrol) by their

The 87Sr/86Sr ratio of horticultural products mostly derives from that of the bioavailable Sr fraction of the soil where they grow and, therefore, varies according to the local geolithological features. This study investigated the intra- and intertree variability of the 87Sr/86Sr ratio in two apple orchards in South Tyrol and its relation with the soil 87Sr/86Sr ratio. In both orchards, a moderate homogeneity of the 87Sr/86Sr ratio was observed among subsamples of the same tree part (shoot axes, leaves, apple peels, and pulps). Moreover, the 87Sr/86Sr ratio homogeneity among tree parts was high intratree and low intertree. The variability of the 87Sr/86Sr ratio within the tree and within the orchard is explained in light of the 87Sr/86Sr ratios of the soil. This 87Sr/86Sr variability within orchards does not preclude its use as a geographical tracer; however, this aspect should be evaluated to correctly design a sampling campaign or to generalize the results.

Die meisten Konsumenten interessieren sich immer stärker für die Herkunft ihrer Lebensmittel. Eine vielversprechende Methode, um die Herkunft von landwirtschaftlichen Produkten zu prüfen ist die Analyse des Strontium (87Sr/86Sr)-Isotopenverhältnisses. Das 87Sr/86Sr-Verhältnis einer Pflanze spiegelt jenes des Bodens auf dem sie wächst wider. Der folgende Beitrag zeigt einige Aspekte des 87Sr/86Sr-Verhältnisses, untersucht während eines 3-jährigen Projektes, und seiner Verwendung als geographischen Indikator für Äpfel auf. In einem ersten Experiment betrachteten wir den Einfluss von landwirtschaftlichen Praktiken und des dadurch extern eingebrachten Strontiums, auf das Isotopenverhältnis der Apfelbäume im Gewächshaus. Die Bäume passten sich langsam an das Isotopenverhältnis im Boden an. Die landwirtschaftlichen Anwendungen hatten nur einen geringen Einfluss auf das 87Sr/86Sr-Verhältnis der Pflanze. Im zweiten Experiment wurden Unterschiede im Isotopenverhältnis zwischen Teilproben eines Pflanzenbestandteiles derselben Pflanze („intra-part“), Unterschiede zwischen den verschiedenen Pflanzenbestandteilen desselben Baumes („intra-tree“), die Unterschiede zwischen den verschieden Pflanzenbestandteilen unterschiedlicher Bäume derselben Obstanlage („inter-tree“) und ihr Zusammenhang mit dem Isotopenverhältnis im Boden, in jeweils zwei Südtiroler Obstanlagen untersucht. „Intra-part“ und „intra-tree“ war das 87Sr/86Sr Verhältniss homogen, allerdings konnten wir Unterschiede zwischen den Bäumen („inter-tree“) der beiden Obstanlagen beobachten. Im letzten Experiment wurden die Analysen auf 41 Obstanlagen in Norditalien ausgeweitet. Das 87Sr/86Sr-Verhältnis von Äpfeln mit geographischer Kennzeichnung aus verschiedenen Gebieten, wurde mit jenen ohne Kennzeichnung verglichen. Das Isotopenverhältnis im Apfel korrelierte stark mit jenem des jeweiligen Bodens der entsprechenden Obstanlage. Einige Gebiete hatten ähnliche geologische Eigenschaften und Isotopenverhältnis, wodurch eine eindeutige Unterscheidung nicht für alle Ortschaften möglich war. Trotzdem kann das 87Sr/86Sr-Verhältnis als geographischer Indikator verwendet werden, jedoch sollten in zukünftigen Studien weitere Parameter miteinbezogen werden.

Different water sources can contribute to plant transpiration in Alpine environments, such as rainfall, snowmelt, irrigation and/or stream waters that are temporarily stored in the vadose and saturated zones. Particularly, the proportion of water uptake from different soil depths can strikingly differ depending on the species and the local environmental conditions such as the availability of freshwater resources, and local climatic and pedological settings.We aim at estimating the relative contributions of different water sources (i.e., soil water at various depths and groundwater) to tree transpiration with the use of stable water isotopes. Our work is part of a wider national project (WATZON: WATer mixing in the critical ZONe) studying the relationship between plants, soil and water in contrasting natural and semi-natural environments of Italy. Here we report the results of monitoring activities in two different ecosystems in South-Tyrol (Eastern Italian Alps): an apple orchard growing on a deep (>2.5 m) sandy soil of the Adige floodplain (Binnenland), and a sub-alpine conifer forest located on steep slopes with a shallow (10-60 cm) skeletal soil (Mazia, 2000 mt a.s.l.), where we selected European larch (Larix decidua) as a model-species. Water (precipitation, stream water, groundwater), soil at different depths and twigs samples were collected fortnightly from May to November 2020, and weather conditions (automatic stations), soil parameters (moisture and temperature) at different depths and sapflow were continuously recorded over the entire period.At both locations, precipitation waters had a heavier isotopic composition than stream water and groundwater, that did not show any significant difference between each other in terms of isotopic signature. While all these potential water sources plotted on the local meteoric water line, shallow soil water samples (5-15 cm) deviated from it revealing a stronger and more variable evaporative fractionation when compared with those of deeper soil (25-65 cm). Xylem water samples from apple trees at Binnenland overlapped with soil water samples, more consistently at 10-30 cm depths. This water mostly derived from infiltrated rainwater but with a non-negligible contribution from groundwater during July and August. In contrast, xylem water from larch trees at Mazia plotted on the local meteoric water line, and had an isotopic composition more similar to that of precipitation than soil water even for samples collected after several days of drying out. As sapflow measurements of larches revealed a continuous transpiration, it is unlikely that trees took up water only soon after precipitation events. Instead, we hypothesize that larches at Mazia likely rely on a water pool which is different from the soil (e.g., rock moisture).These contrasting ecohydrological systems reveal different strategies of water use by dwelling plants in natural and anthropic systems, showing a distinct sensitivity and resilience to changing climate.

Understanding the dynamics and sources of root water uptake in agricultural systems is becoming increasingly important for implementing efficient and sustainable water resources management and, at the same time, for optimizing crop yield and quality under changing climatic conditions. In this work, we adopted the stable isotope approach to investigate the water sources accessed by apple trees in two orchards growing in the upper Etsch/Adige valley (South Tyrol, Eastern Italian Alps). We tested the general hypothesis that soil water, composed of a mixture of rain and irrigation water, was the main source for tree transpiration but that river water and groundwater mixed with soil water and contributed to root uptake for trees growing close to the river and with higher water table. Our results revealed that apple trees during the 2015 and 2016 growing seasons relied mostly on soil water present in the upper 20-40 cm of soils, with an apparently negligible contribution of groundwater and river water, irrespective of the field position across the valley bottom. The isotopic composition of xylem water did not reflect the one of irrigation water (and neither that of groundwater) but rather of rainfall and throughfall, as well as that of soil water. We related this “hidden” tracer signature of irrigation water to the effect of soil evaporation that strongly modified its original isotopic composition: irrigation and rain water infiltrated into the soil and mixed with isotopically fractionated soil water, and trees took up a mixture of water with different isotopic composition compared to the one of the original irrigation source. This work contributes to improve the understanding of water uptake strategies in Alpine apple orchards and paves the way for further analysis on the proportion of irrigation and rain water used by apple trees in mountain agroecosystems.

BACKGROUND The use of PDO (protected designation of origin) and PGI (protected geographical indication) labels allows to protect and promote agricultural products characterized by unique features related to the place of origin and traditional know‐how. However, the presence of non‐authentic products in the market represents a fraud that can be tackled applying analytical techniques combined with chemometric analysis. In this study, we applied multi‐element and multi‐isotope analysis to characterize PDO and PGI apples cultivated in northern Italy, comparing them with Italian apples without labels of geographical indications. RESULTS The multi‐element and multi‐isotope approach allowed to characterize the apples cultivated in northern Italy. Despite a significant effect of the sampling sites on the apple composition, the comparison of the multi‐chemical fingerprint of the apples significantly varied among cultivation areas. Results of this characterization were used to classify samples according to their cultivation area applying a linear discriminant analysis (LDA). Outputs of the LDA showed that correct sample classification can be successfully achieved (balanced accuracy > 96%). Moreover, using a selection of variables, it was possible to correctly classify samples also at regional level. CONCLUSION The presented evidences indicate that the multi‐element and multi‐isotope fingerprint can be successfully applied to traceability studies. The combination of this characterization with chemometric tools allows the classification of Italian apples based on their origin both on a national and regional scale. This approach represents an interesting tool to enhance and protect PDO and PGI Italian products. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Against the background of a future decrease in water availability, there is a need to use irrigation water with higher efficiency. To improve water management, it is crucial to clarify the role of irrigation water compared to soil water and additional water sources, including groundwater, which is often neglected by most water balance models.We used deuterium-enriched water as tracer to distinguish irrigation water from soil water and groundwater and evaluate its contribution to the apple tree water uptake. The study was conducted in an apple orchard (Malus domestica, cv. Pinova) located in a flat area of the Venosta valley (South Tyrol, Italy) characterized by shallow groundwater (about 0.9 m from the ground). Before the experiment, the soil was covered for two weeks to prevent rain and irrigation from entering the soil. In July 2019, deuterium-enriched water (40 L/m2, δ2H = 1500 ‰) was homogenously applied to the soil in four plots. In the proximity of each irrigated plot, not-irrigated trees were present (controls). From both irrigated and control plots, soil, leaf and shoot axis samples were collected starting from 2 hours until 7 days after the irrigation. Total tree and soil water was extracted through cryogenic vacuum distillation. Soil and plant water isotope composition was measured at the IRIS (Isotope Ratio Infrared Spectroscopy) and at the IRMS (Isotope Ratio Mass Spectrometry) analyzer, respectively. Reference ET for the period was 3.3 mm day-1 on average.Soil moisture in both irrigated and control soils decreased from the surface to 0.4-0.5 m soil depth and then progressively increased again until 0.8 m depth, in line with a maximum capillary rise of approximately 0.4 m estimated by models for a silty loam soil. In the upper 0.5 m soil layer, where around 80 % of total fine roots were concentrated, labeled irrigation water represented ca. 20 % of total soil water. The labeled water firstly appeared in the shoots starting from 8 hours from the irrigation (average δ2H = 27.4 ‰) and the deuterium concentration reached its maximum after 24-48 hours from water supply (δ2H = 68.1 ‰). At this time, irrigation water accounted for 8 % of the shoot extracted water. Considering the average deuterium abundance of the extracted water in the first 0.5 m soil layer, where labeled irrigation water mixed with soil water, we estimated that 35-40 % of the shoot water had been absorbed from such a layer. These preliminary results highlight the complexity of soil-water-plant interactions and call for additional investigation to understand the role of the soil water present before irrigation that could be preferentially taken up by roots. Additionally, the contribution of an upward flux from groundwater should be quantified.

The 87Sr/86Sr ratio is an effective geographical tracer for horticultural products. In plants this ratio reflects closely the characteristics of the growing area. However, information about the variability of this parameter when measured in different plant species or cultivars is still scarce. In this work, we have tested the hypothesis that, when plants are growing in the same environment, their 87Sr/86Sr ratio is independent from the plant species or cultivar. For this, four to six vegetable species were collected from two fields in different locations in South Tyrol (Italy), together with the corresponding soils. Additionally, within a single apple orchard located in the same area, apple leaves were collected from trees of five cultivars. The 87Sr/86Sr ratio was measured applying an established and validated method. In general, vegetable species growing in the same field had similar 87Sr/86Sr ratios and showed a lower variability compared to their corresponding soils, while a significant difference was found comparing the 87Sr/86Sr ratios of the two vegetable fields. Apple leaves sampled from different tree cultivars also did not show a significant difference in their 87Sr/86Sr ratio. We concluded that the 87Sr/86Sr ratio in vegetables and apple trees was affected by the soil, but not significantly by the type of species or cultivar. Therefore, within limited areas, the results of the 87Sr/86Sr ratio analysis based on samples of a certain species/cultivar can be extended to other similar plants growing in the same site.

The

The 87Sr/86Sr ratio of a produce is generally linked with the soil geological features of the growing areas. This study aimed at assessing to which extent the addition of external Sr by agricultural practices, like irrigation and mineral nutrient supply, influences this relationship. In a first experiment, oat plants in two soils reflected the 87Sr/86Sr of the soil. However, this link was significantly altered at increasing levels of external Sr soil supplies. In a second experiment, apple trees transplanted in pots modified their original 87Sr/86Sr, which became progressively closer to the soil Sr isotope ratio. The addition of tap water and fertilizers, with different Sr isotopic signatures, slightly affected plant 87Sr/86Sr. Results confirm the potential of the 87Sr/86Sr ratio as a geographical tracer of agricultural commodities, but whenever the range of 87Sr/86Sr variability among soils from different geographical areas is narrow, the influence of external Sr-sources may smooth over these diversities.

Dry cured hams were investigated for their ability to develop red color even at low temperature (3–4 °C) and in the absence of added nitrites; results were compared with those obtained from nitrite-free hams made at conventional warm maturing temperatures. Colorimetric parameters (L*, a*, b*, and hue) and concentration of the main pigments Zn protoporphyrin IX (ZnPP) and heme were measured at three stages of preparation (six, nine, and 12 months), showing that red color was successfully formed at low temperatures, though at a slower rate and less intensively than under warm conditions. Major differences in the pattern of color development were found with the two processing temperatures. While the typical features of an enzyme-dependent mechanism, with a progressive drop in enzyme activity paralleling the synthesis of Zn protoporphyrin IX, were observed at warm temperatures, the same did not occur in cold-made hams, where the enzyme activity was almost unchanged throughout the process. These results, along with data from a descriptive sensory analysis, are supportive of a non-enzymatic mechanism leading to ZnPP (hence the red color) under cold conditions, with an estimated three-month delay compared with nitrite-free hams manufactured in a warm maturing regimen.