LEDFLEX is a micro-lidar dedicated to the measurement of vegetation fluorescence. The light source consists of 4 blue Light-Emitting Diodes (LED) to illuminate part of the canopy in order to average the spatial variability of small crops. The fluorescence emitted in response to a 5-μs width pulse is separated from the ambient light through a synchronized detection. Both the reflectance and the fluorescence of the target are acquired simultaneously in exactly the same field of view, as well as the photosynthetic active radiation and air temperature. The footprint is about 1 m2 at a distance of 8 m. By increasing the number of LEDs longer ranges can be reached. The micro-lidar has been successfully applied under full sunlight conditions to establish the signature of water stress on pea (Pisum Sativum) canopy. Under well-watered conditions the diurnal cycle presents an M shape with a minimum (Fmin) at noon which is Fmin > Fo. After several days withholding watering, Fs decreases and Fmin < Fo. The same patterns were observed on mint (Menta Spicata) and sweet potatoes (Ipomoea batatas) canopies. Active fluorescence measurements with LEDFLEX produced robust fluorescence yield data as a result of the constancy of the excitation intensity and its geometry fixity. Passive methods based on Sun-Induced chlorophyll Fluorescence (SIF) that uses high-resolution spectrometers generate only flux data and are dependent on both the 3D structure of vegetation and variable irradiance conditions along the day. Parallel measurements with LEDFLEX should greatly improve the interpretation of SIF changes.
<p>Within the scope of the TUdi project, EU Horizon 2020 Grant Agreement No 101000224, a questionnaire was responded to by more than 400 farmers from seven countries in Europe and China, aiming to assess farmers' major concerns and develop Decision Support Tools targeted at these issues. One tool currently being developed targets soil erosion and seeks to provide farmers with publicly available historical satellite imagery in a user-friendly platform, as well as guidelines on easy-to-use methodology to assess the degree of soil erosion on the field. The questionnaires also revealed that many farmers do not use official data or digital maps to help make management decisions but are willing to apply simple tools for assessing soil degradation processes. With this, the project hopes to contribute to democratizing access to science, helping farmers &#8211; ultimately, the ones who implement soil conservation practices &#8211; to make data-driven decisions on soil management and exploring alternatives. The preliminary version of this tool will be presented at the workshop.</p><p>Research has been supported by project TUDI (European Union's Horizon 2020 research and innovation program under grant agreement No 101000224)</p>
<p>The sustainability of crop production regarding different climate change scenarios will compromise actors and activities involved in agri-food systems. Furthermore, sustainable development was defined by the World Commission on Environment and Development as the ability to meet present demands without compromising the needs of future generations. In parallel, according to the Food and Agriculture Organization (FAO), land evaluation is the process of projecting land use potential based on its characteristics, and it has been the principal approach used worldwide to manage land use planning. Its use today is required due to changing needs and pressures from decision-making policies or agricultural market tendencies among others, so a rational use of natural land is a crucial goal for economic development. However, future climate change scenarios will modify the actual crop development conditions and must be tackled.</p><p>This paper presents two case studies at the river basin scale to determine the Land Use Suitability (LUS) analysis that is performed according to the FAO framework, thus, areas that are the most suitable for crops using GIS and multicriteria methodology that involves actual and future climatic conditions under different climate change scenarios, crop management practices and edaphological conditions for different crops. The tool developed generates a product that classifies areas suitable for a particular crop from a collection of maps and their corresponding thresholds. The approach involves standardizing the suitability maps, assigning relative importance weights to the suitability maps, and then combining the weights and the standardized suitability maps to obtain a suitability score.</p><p>In this paper, the wheat crop LUS at the J&#250;car River Basin (42,735 Km2, located in Spain) and the cotton LUS at the Pinios River Basin 11,000 km2, located in Greece) are evaluated. Once the LUS is estimated, a collection of yearly thematic maps over both river basins is ready for use by local stakeholders, regarding different climate change scenarios (RCP 4.5 and RCP 8.5).</p><p>These results are part of the EU Horizon 2020 project REXUS (<em>Managing Resilient Nexus Systems Through Participatory Systems Dynamics Modelling</em>), in which local stakeholders, from farmers to land use managers, are collecting and evaluating the information. Our final goal is to provide spatial information for future climate change scenarios that increase land-use knowledge and enhance decision-making policies.</p>
Ledflex is a fluorometer adapted to measure chlorophyll fluorescence at the canopy level. It has been described in detail by Moya et al. (2019), Photosynthesis Research. https://doi.org/10.1007/s11120-019-00642-9. We used this instrument to determine the effect of water stress on the fluorescence of a fescue field under extreme temperature and light conditions through a 12 days campaign during summer in a Mediterranean area. The fescue field formed part of a lysimeter station in "las Tiesas," near Albacete-Spain. In addition to the fluorescence data, the surface temperature was measured using infrared radiometers. Furthermore, "Airflex," a passive fluorometer measuring the filling-in of the atmospheric oxygen absorption band at 760 nm, was installed in an ultralight plane and flown during the most critical days of the campaign. We observed with the Ledflex fluorometer a considerable decrease of about 53% of the stationary chlorophyll fluorescence level at noon under water stress, which was well correlated with the surface temperature difference between the stressed and control plots. Airflex data also showed a decrease in far-red solar-induced fluorescence upon water stress in agreement with surface temperature data and active fluorescence measurements after correction for PS I contribution. Notwithstanding, the results from airborne remote sensing are not as precise as in situ active data.
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