Articles publicats (Grup de Recerca en AgròTICa i Agricultura de Precisió)
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- ItemOpen AccessCorrection to: On-farm experimentation of precision agriculture for differential seed and fertilizer management in semi-arid rainfed zones(Springer, 2024) Videgain Marco, María; Martínez Casasnovas, José Antonio; Vigo-Morancho, Alba; Vidal Cortés, Mariano; García-Ramos, Francisco Javier
- ItemOpen AccessSpatially variable pesticide application in olive groves: Evaluation of potential pesticide-savings through stochastic spatial simulation algorithms(Elsevier, 2021-03-02) Rodríguez-Lizana , Antonio; Pereira , M. J.; Castro Ribeiro , M.; Soares , A.; Azevedo, L.; Miranda-Fuentes, Antonio; Llorens Calveras, JordiSite-specific management using spatial crown volume characterization can greatly reduce the amount of pesticides applied in agricultural treatments performed with air-assisted sprayers, while helping farmers achieve the European legislation on safe use of pesticides. Nevertheless, variable rate treatments in olive groves have received little attention. Thus, field research was conducted in a 20.6-ha traditional olive grove. Two attributes of the trees - tree crown volume (V) and tree projected area - were determined, using 67 samples for V and all trees of the field (1433) for tree projected area. Spatial continuity of both attributes was modelled with exponential variograms. To gain a measure of local uncertainty, stochastic simulation algorithms were applied. One hundred simulated images were obtained for tree projected area using direct sequential simulation. Tree projected area simulations were used to improve spatial prediction of V, more difficult and more expensive to obtain, taking advantage of the high linear correlation between both variables (rxy = 0.72,p < 0.001). Thus, direct sequential cosimulation was employed to predict the spatial distribution of V, obtaining 100 geostatistical realizations of V. In order to estimate the potential reduction of pesticide use in the farm with variable rate treatments, two cut-off values of V were considered (50 and 100 m3crown volume). Local uncertainty, understood as the probability of each tree belonging to a given crown volume interval was determined. Probability maps were further transformed to morphological maps and finally to variable prescription maps. Two scenarios with 2 and 3 management zones (MZs) were obtained. In comparison with a conventional phytosanitary application, the variable rate treatments could reduce the pesticide amounts by 21.3% with 2 MZs, and by 38% with 3 MZs. The joint use of V and tree projected area in stochastic sequential simulation algorithms has shown to be useful to determine MZs in olive groves.
- ItemOpen AccessGeomorphic adjustments to multi-scale disturbances in a mountain river: A century of observations(Elsevier, 2020-04-03) Llena Hernando, Manel; Vericat Querol, Damià; Martínez Casasnovas, José Antonio; Smith, Mark W.In this paper we analyse the geomorphic response of a mountain river (Upper Cinca River, Central Southern Pyrenees) in relation to multi-scale disturbances during almost a century (i.e., 1927–2015). The integration of multiple geomorphic descriptors (i.e., morphology and topography) and disturbances (i.e., floods, land use changes, dams, embankments and gravel mining activities) allows better understanding of the cause-effect relations and their significance. The paper presents a novel methodology integrating the application of SfM-MVS algorithms to historical imagery to extract multitemporal channel topography and morphology; and the use of statistical tools to infer on the existence of significant trends and breakpoints in the temporal evolution of the geomorphic descriptors and disturbances. Results show that afforestation was the main land use change exhibited between 1957 and 2015, although mainly concentrated during 1977–2015. Annual runoff presented a general negative trend with a wet (1959–1983) and dry period (1983–2015). Extensive gravel mining occurred after flood events, together with channel engineering works such as the construction of embankments. These disturbances, together with the construction of three small dams in the headwaters, had a direct impact on lateral connectivity by confining and constraining channels and concentrating flows, resulting inchannel incision and stability. The evolution of the disturbances, process changes and geomorphic descriptors indicated that, during the last century, the river channel is in a transient state, in which the magnitude of the changes oscillate. The river is adjusting to the disequilibrium imposed by multi-scale disturbances acting at different temporal and spatial scales by means of two contrasting channel states. First, Channel State 1 (1927–1984) was characterised by having high geomorphic activity and channel incision. Conversely, Channel State 2 (1984–2015) was characterised, by having a low geomorphic activity, when channel constraining was the dominant process and incision was more localised and marginal. The results of the Upper Cinca may be relevant to infer in future fluvial metamorphosis associated with the effects of global change on water and sediment fluxes in mountain catchments, and to assist objective-based rehabilitation measures of rivers subjected to multi-scale disturbances.
- ItemOpen AccessOn-farm experimentation of precision agriculture for differential seed and fertilizer management in semi-arid rainfed zones(Springer, 2024) Videgain Marco, María ; Martínez Casasnovas, José Antonio; Vigo-Morancho, Alba; Vidal Cortés, Mariano; García-Ramos, Francisco JavierThis study explores the integration of precision agriculture technologies (PATs) in rainfed cereal production within semi-arid regions.Methodsutilizing the Veris 3100 sensor for apparent soil electrical conductivity (ECa) mapping, differentiated management zones (MZs) were established in experimental plots in Valsalada, NE Spain. Site-specific variable dose technology was applied for seed and fertilizer applications, tailoring inputs to distinct fertility levels within each MZ. Emphasizing nitrogen (N) management, the study evaluated the impact of variable-rate applications on crop growth, yield, nitrogen use efficiency (NUE), and economic returns. For the 2021/2022 and 2022/2023 seasons, seeding rates ranged from 350 to 450 grains/m2, and basal fertilizer dosages varied between high and low levels. Additionally, the total nitrogen units were distributed differently between the two seasons, while maintaining a uniform topdressing fertilizer dose across all treatments.ResultsResults revealed a significant increase in yield in MZ 2 (higher fertility) compared to MZ 1 (lower fertility). NUE demonstrated notable improvement in MZ 2, emphasizing the effectiveness of variable-rate N applications. Economic returns, calculated as partial net income, showed a considerable advantage in MZ 2 over MZ 1, resulting in negative outcomes for low-fertility areas in several of the analyzed scenarios, and highlighting the financial benefits of tailored input management.ConclusionThis research provides quantitative evidence supporting the viability and advantages of adopting PATs in rainfed cereal production. The study contributes valuable insights into optimizing input strategies, enhancing N management, and improving economic returns in semi-arid regions.
- ItemOpen AccessLocal factors have a greater influence on the abundance of alfalfa weevil and its larval parasitoids than landscape complexity in heterogeneous landscapes(Springer, 2024) Levi-Mourao, Alexandre; Meseguer Rosagro, Roberto; Madeira, Filipe; Martínez Casasnovas, José Antonio; Costamagna, Alejandro C.; Pons i Domènech, XavierThe alfalfa weevil Hypera postica Gyllenhal (Coleoptera: Curculionidae) is one of the most destructive pests of alfalfa worldwide. Both local and landscape-scale factors can significantly influence crop pests, natural enemies, and the effectiveness of biological control services, but the relative influence of these factors is unclear. Objectives We investigated the influence of the local variables and surrounding landscape composition and configuration on the abundance of alfalfa weevil, and on the abundance and parasitism rates of its larval parasitoids, Bathyplectes spp. Methods We sampled 65 commercial alfalfa fields along the Ebro Basin, Spain, over a period of 3 years, recording the field characteristics and landscape structure at three buffer radii of 250, 500 and 1000 m from the center of each field. Results The abundance of weevil larvae was positively associated with the field perimeter and with the uncut alfalfa surrounding the pipes of the sprinkler irrigation system, but only one configuration variable was positively correlated: the alfalfa edge density. No local characteristics or landscape structures were associated with the abundance of adult weevils. The abundance of Bathyplectes spp. adults was positively associated to local factors such as the densities of alfalfa weevils and aphids. Few landscape structure variables, such as alfalfa edge density and Simpson's Diversity Index, had explanatory value only at 250 m buffer radius. The rate of larval parasitism was affected by local variables, such as alfalfa weevil abundance and field age. Our results provide, for the first time in the Mediterranean region and Europe, evidence of the relative importance of landscape structure and local factors on the abundance of the alfalfa weevil and its larval parasitoids, Bathyplectes spp. The strongest influences were based on local characteristics.