LandSoil: A model for analysing the impact of erosion on agricultural landscape evolution
2012
Ciampalini, Rossano | Follain, Stéphane | Le Bissonnais, Yves | Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)
The purpose of this research was to develop amodel for the analysis of agricultural landscape evolution at a fine spatial resolution scale (1–10m) and a medium-termtemporal scale (10–100years). Themodel (LandSoil: landscape design for soil conservation under Land use and climate change)works at a catchment scale and it is based on the STREAM soil erosion model. It is spatially distributed, event-based, and considers interrill, rill and tillage erosion as the main processes acting in soil redistribution. The specificities of the model include the use of a detailed representation of the agricultural landscape through parameters such as soil surface properties, hydrologic pathways and considering a climate component based directly on rainfall events. In this paper, we present the characteristics of the model and its application to a Mediterranean study area. The model was subjected to a calibration/validation procedure at two different spatial scales (field and catchment) with a medium-term data series of runoff and sediment concentration measurements. A number of medium-term field and catchment simulations were carried out, allowing us to observe landscape evolution under recent and actual agricultural practices and to formulate hypotheses based on changes related to different agricultural patterns and soil uses. Modelling at a field scale using rill, interrill and tillage erosion simulations on reconstructed prior topographic surfaces showed a relationship between observed and simulated topography with a prediction errorb15% and a correlation coefficient (r) of 0.605. A catchment scale analysis of a degraded scenario, maximising hillslope runoff with the removal of all the grass strips between fields, indicated a global increase of the soil erosion rate (+29%), with spatial variability depending on the specific soil use type.
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