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| Gassman, Philip W.; Hauck, Larry M.. |
| This paper briefly describes the environmental component of an integrated modeling system that has been developed for simulating the movement of nutrients (nitrogen and phosphorus) from dairy waste disposal fields through the Upper North Bosque River Watershed (UNBRW) stream network in Erath and Hamilton Countries, Texas, as part of the "Livestock and the Environment: A National Pilot Project" (NPP). The environmental component consists of the Agricultural Policy/Environmental eXtender (APEX) model and the Soil Water Assessment Tool (SWAT). The APEX model is designed to simulate the edge-of-field nutrient runoff and leaching loadings from the application of solid and liquid manure on dairy waste disposal fields that are subsequently routed through the... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Environmental Economics and Policy. |
| Ano: 1996 |
URL: http://purl.umn.edu/18663 |
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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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| Keplinger, Keith O.; Hauck, Larry M.. |
| A model of manure utilization is developed and applied to four types of transportable manure. Model results highlight important response differences among manure types and generally illustrate the diseconomies of manure production. For example, as manure production increases, manure value decreases and excess phosphate applications increase, thereby increasing the potential for phosphorus runoff. Policy scenarios limiting the manure application rate reduce manure value and excess phosphate application. Increasing the ratio of land using manure increases manure value while reducing excess phosphate application. Buildup of soil nutrients reduces manure value, but either increases or decreases excess phosphate application depending on the scenario. |
| Tipo: Journal Article |
Palavras-chave: Linear programming; Manure application; Manure transportation; Manure utilization; Manure value; Optimization; Farm Management. |
| Ano: 2006 |
URL: http://purl.umn.edu/8611 |
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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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