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The interactive APEX (i_APEX) is a user friendly interface for the physical process and environmental fate model, Agricultural Policy/Environmental eXtender (APEX) (Williams et al., 2006, 2008; Williams and Izaurralde, 2006; Gassman et al., 2010). I_APEX is programmed in C++ and performs automatic...

A tool for managing large numbers of APEX runs, handling data input and output. Program Components: • ACCESS Database: Contains input tables used by i_APEX to construct APEX runs and output tables to organize APEX output. • Graphical User Interface: Allows for single runs and ranges...

The purpose of this review and analysis is to provide a basic understanding of the issues related to worldwide hypoxic zones and the range of economic questions sorely in need of answers. We begin by describing the causes and extent of hypoxic zones worldwide, followed by a review of the...

The development of the field-scale Erosion Productivity Impact Calculator (EPIC) model was initiated in 1981 to support assessments of soil erosion impacts on soil productivity for soil, climate, and cropping conditions representative of a broad spectrum of U.S. agricultural production regions....

An integrated modeling system has been constructed for the Upper North Bosque River Watershed (UNBRW) in Erath and Hamilton Counties, Texas, to simulate the movement of nutrients from dairy waste disposal fields. The authors describe the environmental component of that modeling system, focusing...

Delivery coefficients have long been used in economic analysis of policies that seek to address environmental problems like water pollution (Montgomery, 1972). However, the derivation and validity of delivery coefficients have not been examined carefully by empirical analyses. In this study, we...

Over the last two decades, the U.S. federal government spent about 2 billion dollars annually on the conservation of cropland. Such expenditures were supplemented with sizable state and local government funding. However, our understanding is incomplete as to the impacts of these expenditures on...