Jimmy Williams

APEX: A New Tool for Predicting the Effects of Climate and CO2 Changes on Erosion and Water Quality

Several field scale hydrologic/water quality models have been developed to study the impacts of agricultural management practices. The EPIC (Environment Policy Integrated Climate — previously the Erosion Productivity Impact Calculator) model is one of the more popular models, which has been widely applied in the United States and around the world. Such models are limited to small field size areas, where the soil; management, crop, and topography are assumed to be homogeneous. To extend the capabilities of EPIC to simulate large complex fanning systems (multiple fields, soils, rotations, management, etc.), a model called APEX (Agricultural Policy/Environmental eXtender) was developed. In addition to the capabilities of EPIC, APEX has components for routing water, sediment, and chemicals (nutrients and pesticides) across complex landscapes and channel systems to the watershed outlet. The subsurface routing routine to APEX is enhant;ed from that in EPIC and can be used to simulate subsurface processes to a depth of 30 m. In this paper we present an overview of EPIC and APEX, and describe in detail the recently added CO2 component of the model.

Evaluation of new farming technologies in Ethiopia using the Integrated Decision Support System (IDSS)

Highlights • We propose a modeling framework that assesses environmental and economical consequences of agricultural intensification.• Agricultural interventions were evaluated using IDSS in two study sites in the Amhara region of Ethiopia.• IDSS analyses indicate that a significant improvement in family incomes and nutrition can be achieved through the adoption of farming technologies such as irrigation technologies and nutrient management.

Restoration of Military Training Lands: Development of Decision Support Tools

Sustainable management of military training lands is critical to the ongoing mission of preparing U.S. military forces to fight and win wars. Development of next generation biophysical and economic models for planning and assessment of military land restoration programs can provide a vital decision support tool for military land managers worldwide. Providing accurate decision support for determining appropriate best management practice (BMP) selection based on available knowledge is critical and can provide accountability for restoration funding. Utilizing a multitude of data including hydrologic, vegetation, soils and erosion data from the U.S. Armys Fort Hood military installation, a team of scientists is working to parameterize the Agricultural Policy extender (APEX) simulation models capabilities for application on highly disturbed military training lands. Development on lands under such harsh disturbance regimes will provide a robust technology that can be easily adapted to rangeland and other ecosystems under less stressful disturbance conditions. Results of preliminary model parameterizations indicate potential benefits in the development and application of hydrologic models to address erosion reduction practices utilized on Fort Hood.