A11. Model soil erosion under land use change

Title

Improve soil erosion modeling in ELM by considering the effects of land use change and cropland management

Authors

Zeli Tan¹, L. Ruby Leung¹, Hong-Yi Li², Teklu Tesfa¹, Qing Zhu³, Min Chen¹

¹Pacific Northwest National Laboratory, USA

²University of Houston, USA

³Lawrence Berkeley National Laboratory, USA 

Abstract

Soil erosion is an important land surface process that transports enormous amounts of sediment, carbon and nutrients from land to rivers and oceans. Previously, we have developed a soil erosion model in ELM that can simulate soil erosion and erosion induced sediment, C, N and P fluxes under the change of climate. However, this soil erosion model has not considered the impacts of land use change (especially the expansion and abandonment of cropland) and cropland management (such as tillage reduction, plant residual management and irrigation) on soil erosion. As a result, the model cannot make realistic predictions of lateral sediment, carbon and nutrient fluxes. To fill this gap, we will improve the soil erosion model in ELM by turning on the crop model and the irrigation model and the dynamic land use of the cropland land units. We will also add the irrigation water as another force for rainfall-driven erosion, use the modeled plant residual as inputs to calculate the ground cover factor of erosion and integrate the RUSLE tillage factor. In the talk, we will present the data sources for the model improvement and give a preliminary result about how land use change and irrigation could affect the simulation of soil erosion in the recent decades.