Articles publicats (Agrotecnio Center)

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https://repositori.udl.cat/handle/10459.1/57707

Agrotecnio aims to become a reference in Europe addressing all the key elements of the food production chain in an integrated way focusing on target crops and animals of commercial importance, rather than model systems. This later aspect sets our centre apart from other centers which focus on fundamental science and/or model plant and animal systems. As a result we should be able to address fundamental and important questions in the crop/animal of interest and results from our research will be directly and immediately applicable to our target organism. [Més informació]

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Open Access
Methodology for the assessment of leaf area in fruit tree orchards using a terrestrial LiDAR-based system
(Springer Nature, 2025-12-01) Lavaquiol Colell, Bernat; Llorens Calveras, Jordi; Sanz Cortiella, Ricardo; Torrent Martí, Xavier; Plata Moreno, José Manuel; Escolà i Agustí, Alexandre
Accurate estimation of canopy geometric and structural characteristics, such as leaf area (LA), is essential for improving resource efficiency in fruit tree crop management. LA is a key biophysical parameter, influencing physiological processes like carbon fixation, evapotranspiration, and light interception, as well as fruit quality and yield. However, its measurement is complex due to the substantial number of leaves and the three-dimensional nature of tree canopies.An alternative approach, the Projected Tree Row Surface (PTRS), has shown a strong correlation with LA and has been recognized by the scientific community. Despite its robustness, the original PTRS method requires time-consuming manual data collection, which limits its practical application in the field.This study introduces a novel automated methodology for calculating the PTRS, validated using high-resolution ground-truth data providing LA values at 0.1-m intervals along the tree rows. When evaluated on almond, pear, and apple trees as well as vineyards, the method achieved remarkably high correlations between PTRS and LA, with coefficients up to r = 0.97 and r = 0.99 at optimal resolutions (0.1 –0.2 m PTRS per 1 m row section). These results demonstrate that the approach delivers consistent and reliable measurements of LA under diverse field conditions, enabling real-time, high-resolution assessment of tree-row canopies.The automated PTRSn approach enables fast and efficient LA estimation and can be adapted to any point cloud dataset. It supports flexible resolution to balance accuracy and processing time and can be applied to full rows, individual trees, or canopy segments. This methodology represents a step forward in automating LA assessment and supports the development of real-time applications in precision agriculture.
Open Access
Impact of environmental factors on the growth kinetics and mycotoxin profiles of Alternaria spp. in oat grains
(Elsevier, 2026) Llorens-Serentill, Enric; Nazareth de Melo, Tiago; Ramos Girona, Antonio J.; Costa, Jean Carlos Correia Peres; Marín Sillué, Sònia
Alternaria spp. represent a threat to oat safety due to their ability to produce mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), and tentoxin (TEN). This study developed predictive models to describe the growth kinetics and mycotoxin production potential of Alternaria alternata and Alternaria arborescens on γ-irradiated oat grains under combined temperature (5–40 ◦C) and water activity (0.90–0.98) conditions. Four toxigenic isolates from oats (three A. alternata and one A. arborescens) were assessed in a full-factorial design. Mycelial growth was modelled using a primary simplified Baranyi model and secondary models (Cardinal Model with Inflection and gamma-concept) to estimate cardinal parameters (Tmin, Topt, Tmax, aw (min), aw(opt), μRopt). A. alternata exhibited higher thermotolerance (Tmax ≈40 ◦C) than A. arborescens (Tmax ≈ 35 ◦C), with optimal growth at 27–29 ◦C and aw ≥0.98 for both species. Growth and toxin production were strongly restricted below aw 0.90. Under optimal aw conditions, AOH peaked at 30 ◦C for A. alternata isolates (322–398 mg/kg) and at 20 ◦C for A. arborescens (92 mg/kg); AME reached its maximum at 25 ◦C for both species (17–175 mg/kg and 1067 mg/kg for A. alternata and A. arborescens, respectively); TeA also peaked at 25 ◦C (357–800 mg/kg and 357 mg/kg, respectively); and TEN was mainly produced by A. alternata 25 ◦C (1.25–1.8 mg/kg), while A. arborescens produced only minimal levels at 20 ◦C (≤0.05 mg/kg). These differences suggest a potential competitive advantage for the more thermotolerant A. alternata under projected Mediterranean climate warming scenarios, which may alter fungal species dominance and mycotoxin contamination patterns in oats. The predictive models provide a robust quantitative tool for risk assessment and for designing mitigation strategies across oat production and storage.
Open Access
Prescribed burns can trigger Diplodia shoot blight in pine forests
(Elsevier, 2026) Serradó, Francesc; Caballol, Maria; Vendrell, Oriol; Dario, Domingo; Riba, Juan de la; Oliva Palau, Jonàs
Climate change has increased the risk of wildfires, making fuel reduction a key objective in forest management. Prescribed burning is a widely used forest management practice to reduce fuel loads and wildfire risk. In NE Spain, prescribed burns were conducted in a Pinus nigra stand in autumn 2023 and winter 2024, after which extensive crown dieback resembling shoot blight symptoms was observed. Diplodia shoot blight is a disease that affects conifers around the world, particularly pine species. Diplodia shoot blight is caused by the fungus Diplodia sapinea, which shifts from an endophytic to a pathogenic state when the host is under physiological stress such as drought. To determine whether prescribed fire can trigger Diplodia shoot blight, we compared the severity of Diplodia shoot blight in areas subjected to prescribed burns with that of neighbouring control areas. Ground disease assessments were combined with satellite and drone-based multispectral and LiDAR measures. Shoot blight symptoms in burned areas were more than twice as severe as those in unburned areas. Diplodia sapinea was isolated from approximately 70% of pines showing shoot blight symptoms in burned areas. Temporal reconstruction of the outbreak using satellite-based normalised difference vegetation index values showed that the disease appeared after prescribed burning. Drone multispectral imagery combined with a random forest model was a reliable method for large-scale assessment of disease symptoms. When planning prescribed burns in pine forests, managers need to take Diplodia shoot blight into consideration to mitigate the risks of an outbreak.
Embargo
Influence of saprotrophic phytophthora on the decomposition rate of leaf litter in Alpine and Mediterranean streams
(John Wiley & Sons Ltd., 2026) Vieites-Blanco, Cristina; Macià, Héctor; Caballol, Maria; Oliva Palau, Jonàs
The decomposition of leaf litter from the riparian vegetation is a source of nutrients and organic matter for stream food webs. The decomposition rate is influenced by water temperature, leaf characteristics, and aquatic saprotrophic microbial communities. Although the microbial agents Phytophthora lacustris and Phytophthora gonapodyides are frequently isolated from submerged litter, their ecological role in decomposition and their leaf and temperature preferences are largely unknown.In this study, we surveyed Phytophthora colonisation of naturally occurring leaf litter in 26 streams across an altitudinal gradient in the Pyrenees (NE Spain). At 14 of these sites, we also studied Phytophthora colonisation and decomposition (i.e., area and mass loss) of Alnus, Populus and Quercus leaves for 3 months using baiting bags, mimicking the decomposition of leaves that reach streams during leaf fall in autumn. In both experiments, Phytophthora were isolated and identified by sequencing of the ITS region.Leaf species was the main determinant of decomposition, with Alnus leaves decomposing more rapidly than less labile Quercus leaves. The presence of saprotrophic Phytophthora species also correlated with mass loss, especially in the later stages of decomposition. Altitude and climate had the least impact on decomposition, mainly affecting decomposition at the beginning of the decomposition process. The two most common Phytophthora species in Pyrenean streams were P. lacustris (78% of streams) and P. gonapodyides (75%). Phytophthora lacustris was limited to warmer regions, which could be because it has a higher drought-tolerance than P. gonapodyides. Compared with P. lacustris, P. gonapodyides preferred leaves with a lower nitrogen (N) concentration and a slower decomposition.Overall, leaf litter decomposition was correlated with the presence of saprotrophic Phytophthora species: P. gonapodyides was found in leaves that were less decomposed (across N-rich and N-poor litter species) than those of P. lacustris, indicating that they may play different roles in the decomposition process. These species differed in their tolerance to higher and lower temperatures and in their leaf chemical composition preference and, therefore, their ecological niche also differed.Predicted temperature increases could reduce the potential distribution of P. gonapodyides, but the implications for the decomposition of N-poor litter at the early stage of the decomposition process would depend on the extent of the contribution of P. gonapodyides to this process.
Open Access
Chemical controls on iron distributions across the subsurface South Pacific Ocean
(Nature, 2026) Gledhill, M.; Gosnell, K.; Humphreys, M. P.; Delaigue, L.; Helle, N.; Zhu, K.; Lodeiro, Pablo; Rey-Castro, Carlos; Achterberg, E. P.
Iron and nitrogen are the primary nutrients that limit productivity in the ocean. While nitrogen cycling is largely controlled by biology, iron cycling is strongly determined by chemistry because iron losses are driven by abiotic formation of authigenic mineral iron. Here, we apply a mechanistic approach to examine how organic matter across the dissolved-particulate size spectrum controls authigenic iron formation in subsurface waters (>250 m) of the South Pacific Ocean. We find that accounting for the chemical heterogeneity of organic matter is essential for predicting widespread authigenic iron formation. Predicted dissolved and particulate iron concentrations matched observations in the ocean interior, while discrepancies were linked to kinetic control of authigenic iron formation or inputs of particles from the seafloor. Our work shows the need to represent the complexity of abiotic interactions to better resolve the interplay of chemical and biological controls on ocean iron cycling

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