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WATERSHED ECOSYSTEM NUTRIENT DYNAMICS (WEND). Modeling Phosphorus (P) at a Watershed Scale: A Mass Balance Approach. WEND. A New Tool for Phosphorus (P) Management Using Off-the-Shelf Software Used to Balance the Input and Output of P into, out of, and within a Watershed.
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WATERSHED ECOSYSTEM NUTRIENT DYNAMICS (WEND) Modeling Phosphorus (P) at a Watershed Scale: A Mass Balance Approach USDA, NRCS, Watershed Science Institute
WEND • A New Tool for Phosphorus (P) Management Using Off-the-Shelf Software • Used to Balance the Input and Output of P into, out of, and within a Watershed USDA, NRCS, Watershed Science Institute
Basic Watershed Concepts • Watersheds Store and Cycle P based on: • biological, physical, chemical mechanisms • management • land use development. • Phosphorus is stored in soils, sediments, biomass and wastes. USDA, NRCS, Watershed Science Institute
Basic Watershed Concepts • Phosphorus cycles and changes form due to biological, physical and chemical mechanisms. • Phosphorus cycles and changes location within and among land uses (sectors) within a watershed. USDA, NRCS, Watershed Science Institute
Sectors that Process Phosphorus • Agricultural • Cropland • Pasture • Animal Operations • Urban and Industrial • Woodland USDA, NRCS, Watershed Science Institute
P movement into, out of and within these sectors can be modeled using mass balance and dynamic simulation techniques. USDA, NRCS, Watershed Science Institute
Conceptual Model USDA, NRCS, Watershed Science Institute
Four Watersheds Modeled to Date USDA, NRCS, Watershed Science Institute
Models Developed for Different Land Uses and Animal Operations 1. The WEND-1 models the 275,000 ha (679,000 ac) Winooski River Watershed in Vermont, USA • Dairy • Silage Corn, • Hay, Pasture USDA, NRCS, Watershed Science Institute
Models Developed for Different Land Uses and Animal Operations 2. The WEND-IBW models the 77,000 ha (190,000 ac) Inland Bays Watershed in Delaware, USA • Poultry • Corn-Wheat- Soybean Rotation USDA, NRCS, Watershed Science Institute
Models Developed for Different Land Uses and Animal Operations 3. The WEND-LCW models the 23,800 ha (58,700 ac) Little Cobb River Watershed in Minnesota, USA • Swine • Oats, Soybeans, & Corn USDA, NRCS, Watershed Science Institute
Models Developed for Different Land Uses and Animal Operations 4.The WEND-Eucha models the 93800 ha (231,700 ac) Lake Eucha Watershed in Arkansas and Oklahoma, USA • Poultry • Pasture USDA, NRCS, Watershed Science Institute
Characteristics of Watersheds Modeled USDA, NRCS, Watershed Science Institute
Characteristics of Watersheds Modeled USDA, NRCS, Watershed Science Institute
Monitored Data vs. Modeled Estimates USDA, NRCS, Watershed Science Institute
Management AlternativesSimulated with WEND • Erosion Control • Manure Export USDA, NRCS, Watershed Science Institute
Management AlternativesSimulated with WEND • Increased Treatment of Point Sources • Animal Reduction USDA, NRCS, Watershed Science Institute
Conclusions • WEND Models Are Valid For Evaluating P Management Scenarios For Watersheds • P Management Strategies Must Be Tailored To Fit Conditions in a Individual Watershed USDA, NRCS, Watershed Science Institute
Conclusions • P Sources Change Over Time • A Reduction in Non-Point Source P Export to a Drainage Net May Take Years USDA, NRCS, Watershed Science Institute
For Additional Information David Anderson NRCS Watershed Science Institute 402-437-5178x46 danderso@unlserve.unl.edu USDA, NRCS, Watershed Science Institute