Monitoring wheat phenology and irrigation in Center of Morocco: on the use of relationship between evapotranspiration, crops coefficients, leaf area index and remotely-sensed vegetation indices
Autor: | Rachid Hadria, Salah Er-Raki, Philippe Maisongrande, Julio Cesar Rodríguez, Bernard Mougenot, A.G. Chehbouni, G. Boulet, Vincent Simonneaux, Jamal Ezzahar, Said Khabba, R. Escadafal, B. Duchemin, Albert Olioso, J. C. B. Hoedjes, M. H. Kharrou |
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Přispěvatelé: | Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS) |
Jazyk: | angličtina |
Rok vydání: | 2006 |
Předmět: |
Meteorologie en Luchtkwaliteit
winter-wheat 010504 meteorology & atmospheric sciences BILAN HYDRIQUE 02 engineering and technology VEGETATION INDICES 01 natural sciences MOROCCO information PHENOLOGIE Evapotranspiration PHENOLOGY 020701 environmental engineering svat models INDICE DE VEGETATION Water Science and Technology Transpiration 2. Zero hunger region EVAPOTRANSPIRATION command area TELEDETECTION SPATIALE Vegetation PE&RC radiative-transfer models EVAPORATION bidirectional reflectance BLE high-resolution radiometer Irrigation Meteorology and Air Quality NDVI NORMALISED DIFFERENCE VEGETATION INDEX water 0207 environmental engineering WHEAT Soil Science Context (language use) CROP COEFFICIENTS BILAN ENEGETIQUE Normalized Difference Vegetation Index AGROMETEOROLOGIE CULTURE IRRIGUEE Leaf area index [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment 0105 earth and related environmental sciences Earth-Surface Processes Hydrology CAPTEUR AVHRR MODELISATION LAI Crop coefficient sensing data assimilation Environmental science LEAF AREA INDEX Agronomy and Crop Science |
Zdroj: | Agricultural Water Management Agricultural Water Management, Elsevier Masson, 2006, 79 (1), pp.1-27. ⟨10.1016/j.agwat.2005.02.013⟩ Agricultural Water Management 79 (2006) 1 Agricultural Water Management, 79(1), 1-27 |
ISSN: | 0378-3774 |
DOI: | 10.1016/j.agwat.2005.02.013⟩ |
Popis: | The monitoring of crop production and irrigation at a regional scale can be based on the use of ecosystem process models and remote sensing data. The former simulate the time courses of the main biophysical variables which affect crop photosynthesis and water consumption at a fine time step (hourly or daily); the latter allows to provide the spatial distribution of these variables over a region of interest at a time span from 10 days to a month. In this context, this study investigates the feasibility of using the normalised difference vegetation index (NDVI) derived from remote sensing data to provide indirect estimates of: (1) the leaf area index (LAI), which is a key-variable of many crop process models; and (2) crop coefficients, which represent the ratio of actual (AET) to reference (ET0) evapotranspiration. A first analysis is performed based on a dataset collected at field in an irrigated area of the Haouz plain (region of Marrakesh, Central Morocco) during the 2002–2003 agricultural season. The seasonal courses of NDVI, LAI, AET and ET0 have been compared, then crop coefficients have been calculated using a method that allows roughly to separate soil evaporation from plant transpiration. This allows to compute the crop basal coefficient (Kcb) restricted to the plant transpiration process. Finally, three relationships have been established. The relationships between LAI and NDVI as well as between LAI and Kcb were found both exponential, with associated errors of 30% and 15%, respectively. Because the NDVI saturates at high LAI values (>4), the use of remotely-sensed data results in poor accuracy of LAI estimates for well-developed canopies. However, this inaccuracy was not found critical for transpiration estimates since AET appears limited to ET0 for well-developed canopies. As a consequence, the relationship between NDVI and Kcb was found linear and of good accuracy (15%). Based on these relationships, maps of LAI and transpiration requirements have been derived from two Landsat7-ETM+ images acquired at the beginning and the middle of the agricultural season. These maps show the space and time variability in crop development and water requirements over a 3 km × 3 km irrigated area that surrounds the fields of study. They may give an indication on how the water should be distributed over the area of interest in order to improve the efficiency of irrigation. The availability, in the near future, of Earth Observation Systems designed to provide both high spatial resolution (10 m) and frequent revisit (day) would make it feasible to set up such approaches for the operational monitoring of crop phenology and irrigation at a regional scale. |
Databáze: | OpenAIRE |
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