Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Use of Precision Agricultural-Landscape Modeling System (PALMS) for estimating the effects of cultural practices on infiltration, runoff and erosion

Auteur : Álvarez Acosta, C.

Université de soutenance : Wageningen University

Grade : Master of Science (MS) 2009

Résumé
Agriculture worldwide and particularly in the United States, is under increasing pressure to reduce the negative environmental consequences of its manageent and cultural practices, but at the same time, enhance its production. This research was conducted in a 63.8ha field near Lamesa, Texas, USA. Our objective was to evaluate water harvested from rain and the reduction of soil loss under semiarid conditions, by comparing planting dryland crops in a circular pattern instead of the traditional linear rows. Further, we also evaluated the effect of tillage operations in circular versus linear rows. The Precision Agricultural‐Landscape Modeling System (PALMS) was used to calculate infiltration, runoff and erosion in the field comparing linear versus circular rows at a landscape scale. Textural analysis and soil hydraulic parameters (Ksa, water retention curve) were measured across the field and used as input and also to calibrate the model for the study area. The study field has an average slope of 0.33 % and thus erosion calculations showed that soil erosion was minimal with only a slight redistribution of soil within the field boundary conditions. PALMS calculations also showed that planting a dryland crop, such as sorghum (Shorgum bicolor L.) in a circular pattern and not in the traditional linear row, did not modify the annual infiltration (254 mm yr1), runoff (22,000 m3 ha1 yr1) and erosion (1.2 Mg ha1 yr1). Although PALMS yielded reasonable estimates, further calibration is needed in order to further verify calculations of all model outputs.

Mots clés : precision agriculture / simulation models / soil degradation / erosion / runoff / hydrology / infiltration / texas / usa

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