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Title: New SWAT tile drain equations: Modifications, Calibration, Validation, and Application

item Moriasi, Daniel
item Gowda, Prasanna
item Arnold, Jeffrey
item MULLA, DAVID - University Of Minnesota
item ALE, SRINIVASULU - Texas A&M Agrilife
item Steiner, Jean
item Tomer, Mark

Submitted to: Journal of Environmental Quality
Publication Type: Abstract Only
Publication Acceptance Date: 6/19/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: Abstract Only

Technical Abstract: Subsurface tile drainage is a commonly used agricultural practice to enhance crop yield in poorly drained but highly productive soils in many other regions of the world. However, the presence of subsurface tile drainage systems also expedites the transport of nitrate-nitrogen (NO3-N) and other chemicals to surface waters. Hydrologic and water quality models such as the Soil and Water Assessment Tool (SWAT) are widely used to simulate tile drainage systems at various spatial scales. The tile drain algorithms are constantly under modifications as SWAT model gets used and users provide feedback. The most recent (New) tile drain algorithm in SWAT is based on the Hooghoudt and Kirkham equations. Recent modifications to the new tile drain equations will be presented. The modified equations in SWAT are calibrated, validated, and applied in small plots in Waseca located in southern Minnesota to determine the impact of nitrogen (N) fertilizer application and tile drain configuration on nitrate leaching. Detailed results will be presented but overall long-term simulation results indicated that greatest reductions in NO3-N losses can be achieved with reduction in the N application rates. These results showed potential of the new tile drainage equations in SWAT to simulate the effects of tile drain configurations on drainage and associated NO3-N losses.