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Accueil du site → Doctorat → États-Unis → 1997 → Simulation of light interception, water balance and crop production in parkland type agroforestry systems

Washington State University (1997)

Simulation of light interception, water balance and crop production in parkland type agroforestry systems

Badini, Oumarou

Titre : Simulation of light interception, water balance and crop production in parkland type agroforestry systems

Auteur : Badini, Oumarou

Université de soutenance : Washington State University

Grade : Doctor of Philosophy (PhD) 1997

Résumé
In order to optimize crop productivity in low-input agricultural systems such as the natural parklands systems in West Africa, there is a need for a better assessment of the overall system performance. Simulation models have proved to be useful in assessing production potential in agricultural systems, and can be used for the evaluation of complex systems such as the parkland systems. In the present study, an existing simple soil water balance model has been modified and improved to include the effect of a single tree on microclimate, water balance and understorey crop productivity. Two studies were conducted. The first study examines the problem of light transmission in an individual tree canopy. Specific objectives were to model light transmission by the tree canopy and to assess the spatial and temporal distribution of the tree’s shade on the ground. To corroborate the model, light interception data were collected from a walnut tree (Juglans nigre) in Pullman, WA in 1955. Overall, results suggested that the model correctly simulated light transmission by the tree as a function of direction, time of the day and distance from the tree trunk. The objectives of the second study were to model and quantify the changes in microclimate, water budget and crop performance due to the presence of an individual tree in three agroclimatic zones of Burkina Faso (arid, semi-arid and sub-humid). The simulation results indicated that the presence of the tree reduced maximum soil temperatures, reduced soil water evaporation, and enhanced soil water storage in all zones. For light transmission less than 50%, simulated crop yields under the tree were only 20 to 30% of the values in the open in the semi-arid and sub-humid zones. From comparisons of measured and predicted soil temperatures, light transmission and sorghum production data, it is apparent that the model is a useful tool for assessing water budgets and crop growth in parkland type agroforestry systems.

Mots clés : Agronomy, Burkina Faso, Soil sciences, Biological sciences

Présentation (PROQUEST)

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