Location: Agricultural Systems Research Unit
2012 Annual Report
Objective 2. Using data from Colorado and the Midwest, improve model components to quantify and assess spatially targeted agricultural conservation effects on water quantity and quality. [Contributes to Problem Area #4, Improving Watershed Management and Ecosystem Services in Agricultural Landscapes, Problem Statement 4.1 of the new National Program (NP) 211 Action Plan (FY 2011 – 2015)]
Objective 3. Simulate the combined effects of projected climate change on crop production, water use, and nitrate transport, and assess potential cropping system adaptations at field to sub-basin scales in Colorado. [Contributes to Problem Area #4, Improving Watershed Management and Ecosystem Services in Agricultural Landscapes, Problem Statement 4.3 of the new National Program (NP) 211 Action Plan (FY 2011 – 2015)]
This project focuses on developing simulation tools for evaluating and proposing solutions to critical emerging problems in diverse agricultural systems over scales ranging from approximately 50 to 50,000 ha under current and future conditions. The component-based AgroEcoSystem-Watershed (AgES-W) model, developed in the Object Modeling System (OMS) framework, explicitly simulates the hydrologic and agronomic responses from spatially distributed land use, management, and weather conditions across inter-connected ecosystem response units (ERUs). AgES-W will be enhanced for:.
The AgroEcoSystem-Watershed (AgES-W) computer model was modified to input and output soil water contents by horizon (vertical layer in the model). This improved the user experience and made it possible to calibrate the model to match measured soil water contents in different horizons. Subsequently a model parameter estimation tool, called LUCA, was revised and applied to automatic calibration of model parameters by soil horizon. LUCA was also used for autocalibration of AgES-W nitrogen and sediment input parameters with subsequent evaluation of the tool using observed water quality data from the Upper Cedar Creek Watershed in northwest Indiana. These advancements will facilitate model calibration and application at watershed scales.
The AgroEcoSystem-Watershed model graphical user interface (AgESGUI) underwent detailed debugging and evaluation and was further enhanced with additional options for scenario comparisons and model spatial and temporal output visualization. Completion of AgESGUI will expedite setup and simulation of the underlying AgES-W simulation model and facilitate model application by new and existing users.
Agricultural watersheds within the Cache la Poudre Watershed in Colorado were delineated for simulation across a range of scales (field, farm and subwatershed), where smaller watersheds are “nested” within larger watersheds to aggregate the responses across scales. Initial model runs are based on these watershed delineations, and the software tools have undergone enhancements to redefine model simulation units and watershed areas as needed in the future.
In consultation with our collaborator in Iowa, key conservation practices for the South Fork Watershed in Iowa were selected to simulate using the AgroEcoSystem-Watershed (AgES-W) model. The high priority practices include grassed waterways, tile intake replacement/plugging, filter strips and riparian buffers. AgES-W will be applied with and without these practices to estimate the potential benefits in terms of nitrate transport. Some modifications to the model are needed to simulate the overland and subsurface processes of water flow and nitrate transport.