Articles publicats (Ciència i Enginyeria Forestal i Agrícola)
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- ItemOpen AccessPlasticity of wheat yield components in response to N fertilization(Elsevier, 2023) Lenoir, Arthur; Slafer, Gustavo A.; Siah, Ali; Dumont, BenjaminNitrogen fertilization is one of the major issues of crop productions in west-Europe. Every year, large quantities of synthetic nitrogen are used to fertilize crops, such as winter wheat (Triticum aestivum), and ensure them high yielding conditions. In return, substantial amount of nitrogen ends up in the environment where it generates pollutions. The combination of strategic and tactical approaches has been suggested to improve the accuracy of nitrogen fertilization decisions and their implementation. Combining strategic and tactical approaches requires a detailed understanding of the dynamic of nitrogen use by the plant to both anticipate and adapt fertilization practices. Inspired by the concept of yield component phenotypic plasticity, this study aimed to analyze the influence of nitrogen fertilization dynamics on yield elaboration and infer strategic decision rules dedicated to wheat yield optimization in a Belgian context. The analysis, implemented from ten-year experiment, was conducted in two different steps. (1) We characterized the effect of nitrogen fertilization on yield and yield components when the crop was submitted to different agro-pedo-climatic contexts, (2) we analyzed the specific influence of nitrogen fertilization dynamic on yield elaboration, normalizing the variables of the experiment to exclude genetic and environmental influences. The study revealed that highest nitrogen fertilization did not automatically lead to the highest yields. High nitrogen fertilization contributed to increase the negative trade-offs between yield components, which limited the efficiency of nitrogen supplies. Conversely, a balanced dynamic of nitrogen supplies was essential to reach high yields while supplying effective amount of nitrogen. From this Belgian dataset, optimal nitrogen fertilization strategies supposed early nitrogen supplies split in two applications to support the initiation phases of grains per m² and another nitrogen supply at flag leaf stage to maintain components of grain per m² while still allowing grain filling. This fertilization structures, adapted to different pedoclimatic contexts would support strategic approach in crop nitrogen nutrition.v
- ItemOpen AccessDietary range varies among Aphis craccivora populations associated with different host plants: insights into the alfalfa-cowpea aphid system in Spain(WILEY, 2025) Meseguer Rosagro, Roberto; Levi-Mourao, Alexandre; Pons i Domènech, XavierAgroecosystems are frequently disrupted by aggressive management practices. In the case of alfalfa, regular cutting events during the season cause abrupt resource depletion, often leading to the spillover of insects into nearby areas. In this study, we assessed whether alfalfa populations of the polyphagous aphid Aphis craccivora Koch (Hemiptera: Aphididae) can utilize black locust and vetch, two common plants found near alfalfa fields, as alternative hosts following cutting events. We also determined the ability of these plants to act as A. craccivora reservoirs for the recolonization of alfalfa stands once regrowth occurs. To address these questions, we conducted host specialization trials involving host shifting in three different A. craccivora populations collected from alfalfa, black locust, and vetch. We recorded a comprehensive set of life history parameters using the two-sex life table procedure. The degree of host specialization varied among different A. craccivora populations. The alfalfa-origin population showed relatively good performance when shifted to either black locust or vetch, suggesting these plants may act as refuges for population rebuilding after cutting events, until alfalfa regrowth allows for recolonization. In contrast, populations originating from black locust or vetch performed very poorly on alfalfa, suggesting the colonization of alfalfa fields by these populations is unlikely. The mechanisms underlying host specialization in different A. craccivora populations and the observed differences in dietary diversity are discussed. This study provides valuable insights into the ecology of this insect in the most significant Spanish alfalfa-producing region.
- ItemOpen AccessBiophysical drivers of Pinus nigra subsp. salzmannii post-fire regeneration: role of fire refugia(Springer Science and Business Media B.V., 2025) Méndez-Cartín, Ana Lucía; Coll Mir, Lluís; Krawchuk, Meg A.; Gelabert Vadillo, Pere Joan; Fontova Musté, Anna; Améztegui González, AitorContext: Recent shifts in fire regimes challenge recovery of forest ecosystems. In Catalonia, Spain, the capacity of Pinus nigra to persist has been affected by recent high severity fires. Objectives: To understand the biophysical conditions that support P. nigra recovery after high severity fire, we investigate the main biophysical drivers—seed availability, community interactions, water, and nutritional constraints—affecting post-fire regeneration patterns in Catalonia. Methods: We identified fire refugia and calculated the distance-weighted refugia density (DWD) across four fire footprints to represent the seed source abundance. We surveyed abundance of regeneration and shrub cover on 270 sites. We tested identical statistical models for “inside” and “outside” fire refugia, to assess the role of fire refugia and main biophysical drivers on post-fire regeneration. Results: The DWD had a positive effect on post-fire P. nigra recovery, with a stronger effect outside refugia than inside. Inside fire refugia, canopy trees had a sheltering effect on post-fire regeneration, reducing negative effects of heat load, particularly at higher aridity plots. Presence of Rubus spp. broadleaf shrubs enhanced the abundance of regeneration both inside and outside refugia. Total shrubs cover negatively impacted regeneration inside refugia and sites with greater aridity outside refugia but exerted a facilitative effect on P. nigra regeneration outside of fire refugia at sites with lower heat load. Conclusions: Seed source abundance is an integral driver of post-fire regeneration however, biophysical site conditions are important filters that amplify or diminish regeneration. This ecological information can be used to tailor post-fire management goals for forest recovery.
- ItemOpen AccessInfluence of soil management and previous crop nitrogen fertilization on alfalfa productivity in Mediterranean agroecosystems(Elsevier, 2025-05-05) Fernandez-Ortega, Jesús; Cantero-Martínez, CarlosContext Intensive maize (Zea mays L.) cultivation in Mediterranean irrigated systems has led to soil degradation and excessive nitrogen (N) accumulation, increasing the risk of environmental contamination. Alfalfa (Medicago sativa L.), a perennial legume with low input requirements, offers a sustainable alternative that can improve soil structure and reduce residual N. However, limited research has assessed its establishment under different tillage systems and its capacity for biological N fixation in Mediterranean conditions. Objective This study aimed to evaluate the impact of transitioning from intensive maize cultivation to alfalfa under different tillage systems. Specifically, we hypothesized that (i) No-tillage enhances alfalfa establishment and yield, (ii) biological N fixation is higher under no-tillage, and (iii) lower residual N levels from maize would favors biological N fixation and alfalfa productivity. Methods A three-year field experiment (2019–2021) was conducted in northeastern Spain using a randomized block design with two factors: tillage system (conventional tillage, CT, vs. no-tillage, NT) and the residual soil nitrogen levels resulting from fertilization of the preceding maize crop (0, 200, and 400 kg N ha⁻¹). Alfalfa biomass yield was measured at each harvest. Soil mineral N and moisture were monitored, and biological N fixation was quantified using the natural ¹ ⁵N abundance method. Soil structure was assessed through macroaggregate stability analysis. Results NT significantly improved initial alfalfa establishment, resulting in a 32 % higher biomass yield in the first year (3190 vs. 2415 kg ha⁻¹ under NT and CT, respectively). However, by the second year, yield differences between tillage systems disappeared. Biological N fixation was higher in NT during the first year (111 vs. 77 kg N ha⁻¹ in CT) but equalized across treatments over time. Residual N fertilization delayed nodulation and biological N fixation, leading to lower yields in fertilized plots by the end of the first year. The duration of the experiment was sufficient to improve soil macroaggregate stability under CT, reaching values similar to those observed in NT by the end of the study. Conclusions NT accelerated alfalfa establishment and enhanced biological N fixation in early growth stages, while alfalfa itself restored soil properties over time, reducing differences between tillage systems. Excessive residual N from maize hindered biological N fixation and negatively impacted alfalfa yields. Significance This study underscores the benefits of integrating no-tillage alfalfa into Mediterranean irrigated systems as a sustainable strategy to improve soil health, optimize N use, and enhance long-term productivity in intensive crop rotations.
- ItemOpen AccessStabilizing adaptation in an invasive species: alfalfa weevil as a case study(WILEY, 2025) Gutierrez, Andrew Paul; Ponti, Luigi; Levi-Mourao, Alexandre; Pons, Xavier; Cure, Jose Ricardo; Neteler, Markus; Simmons, GeorgeStudies on the phylogeographic structure of species (strains) have yielded insights into their geographic distribution but tell less about strain's capacity to invade novel environments. Extensive age-specific life table data on two strains of the invasive Palearctic alfalfa weevil, Hypera postica (Gyllenhal) (i.e., Ebro Valley, Spain (S) and Hamadan, Iran (I) strains) having disparate vital rates, are used to develop weather-driven physiologically based demographic models (PBDMs) of their biology. The PBDMs are used to explore prospectively their invasive potential across much of the Holarctic. Using N.E. Gilbert's theory that fecundity is selected to the level appropriate for the population in its environment, we explore the interacting effects of multiples of observed fecundity, temperature-dependent mortality and density-dependent population growth constraints on stabilizing adaptation in strains S and I to weather in their native area. Aestivating adults (Aaes$$ {}<^>{aes}A $$) bridge the critical winter period, and their annual production is used as a metric of adaptation. Maximization of Aaes$$ {}<^>{aes}A $$ in the native environments supports Gilbert's supposition. The S and I strains have wide invasive potential, and we posit stabilizing selection for maximizing Aaes$$ {}<^>{aes}A $$ would occur after successful invasion of novel environments. We propose that the evolving adaptation of an invasive strain to extant and climate change weather can be examined by periodic updates of the biodemographic biology in the weather-driven PBDMs.