As nutrients and sediment in agricultural watersheds continue to degrade water quality, attention is increasingly given to reverse auctions to cost-effectively address these pollutants. Typically, reverse auctions include a selection process which depends on both the monetary bid and a ranking...

In 2008, the hypoxic zone in the Gulf of Mexico, measuring 20720 km2, was one of the two largest reported since measurement of the zone began in 1985. The extent of the hypoxic zone is related to nitrogen and phosphorous loadings originating on agricultural fields in the upper Midwest. This...

A watershed-based modeling system is developed to assess alternative nutrient abatement policies, including fertilizer taxes, application caps, and uniform reductions. A microeconometric model of nutrient use is estimated using farm-level data, prices, and spatially detailed soil and land...

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....

This study investigates the implications of treating different environmental benefits as the primary target of policy design. We focus on two scenarios, estimating for both of them in-stream sediment, nutrient loadings, and carbon sequestration. In the first, we assess the impact of a program...

A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW...

The Soil and Water Assessment Tool (SWAT) model is a continuation of nearly 30 years of modeling efforts conducted by the U.S. Department of Agriculture (USDA), Agricultural Research Service. SWAT has gained international acceptance as a robust interdisciplinary watershed modeling tool, as...

The Agricultural Policy Environmental eXtender (APEX) model was developed by the Blacklands Research and Extension Center in Temple, Texas. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land use across a broad...