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| Wang, Erda; Williams, Jimmy R.; Little, Bertis B.. |
| The Environmental Policy Integrated Climate (EPIC) model was modified to include hail weather events, completing modification needed to simulate the four most frequent causes of crop yield loss (hail, too wet, too cold, too dry) in the Kansas crop insurance program. Yields were simulated for corn, wheat, soybeans, and sorghum. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Crop Production/Industries. |
| Ano: 2005 |
URL: http://purl.umn.edu/35467 |
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| Gassman, Philip W.; Williams, Jimmy R.; Wang, Xiuying; Saleh, Ali; Osei, Edward; Hauck, Larry M.; Izaurralde, R. Cesar; Flowers, Joan D.. |
| 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 range of agricultural landscapes, including whole farms and small watersheds. The model can be configured for novel land management strategies, such as filter strip impacts on pollutant losses from upslope cropfields, intensive rotational grazing scenarios depicting movement of cows between paddocks, vegetated grassed waterways in combination with filter strip impacts, and land application of manure removal from livestock feedlots or waste storage ponds. A... |
| Tipo: Report |
Palavras-chave: APEX; Best management practices; Farm and watershed simulations; Soil carbon; Water quality; Environmental Economics and Policy. |
| Ano: 2009 |
URL: http://purl.umn.edu/49156 |
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| Schneider, Uwe A.; McCarl, Bruce A.; Murray, Brian C.; Williams, Jimmy R.; Sands, Ronald D.. |
| We use the Agricultural Sector Model to analyze the economic potential of soil carbon sequestration as one of several agricultural greenhouse gas emission mitigation strategies, including afforestation. For low incentives on carbon emission savings, agricultural soil carbon sequestration is the most cost-efficient strategy. As incentive levels increase above $50 per ton of carbon equivalent, afforestation and biofuel production become the key strategies, while the role of soil carbon diminishes. If saturating sinks are discounted based on their net present value, the competitive economic equilibrium among agricultural mitigation strategies shifts away from soil carbon sequestration and afforestation and toward more biofuel production. Regardless of the... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Afforestation; Agricultural Sector Model; Carbon sequestration dynamics; Economic potential; Emission leakage; Greenhouse gas emission mitigation; Sink saturation; Technical potential; Volatility; Environmental Economics and Policy. |
| Ano: 2001 |
URL: http://purl.umn.edu/18378 |
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| Kramer, L.A.; Gassman, Philip W.; Chung, S.W.; Williams, Jimmy R.; Gu, R.. |
| The Erosion Productivity Impact Calculator (EPIC) model was validated using long-term data collected for two southwest Iowa watersheds in the Deep Loess Soil Region, which have been cropped in continuous corn Zea Mays L. under two different tillage systems (conventional tillage and ridge-till). The annual hydrologic balance was calibrated for both watersheds during 1988-94 by adjusting the runoff curve numbers and residue effects on soil evaporation. Model validation was performed for 1976-87, using both summary statistics (means or medians) and parametric and nonparametric statistical tests. The errors between the 12-year predicted and observed means or medians were less than 10 percent for nearly all of the hydrologic and environmental indicators, with... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Resource /Energy Economics and Policy. |
| Ano: 1995 |
URL: http://purl.umn.edu/18399 |
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| Gassman, Philip W.; Williams, Jimmy R.; Benson, Verel W.; Izaurralde, R. Cesar; Hauck, Larry M.; Jones, C. Allan; Atwood, Jay D.; Kiniry, James R.; Flowers, Joan D.. |
| 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. The first major application of EPIC was a national analysis performed in support of the 1985 Resources Conservation Act (RCA) assessment. The model has continuously evolved since that time and has been applied for a wide range of field, regional, and national studies both in the U.S. and in other countries. The range of EPIC applications has also expanded greatly over that time, including studies of (1) surface runoff and leaching estimates of nitrogen and... |
| Tipo: Working or Discussion Paper |
Palavras-chave: APEX; Carbon sequestration; Climate change; EPIC; Modeling; Soil erosion; Water quality; Research Methods/ Statistical Methods. |
| Ano: 2005 |
URL: http://purl.umn.edu/18372 |
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