Thoroughly tested simulation models are needed to help quantify the long-term effects of agriculture. We evaluated the Root Zone Water Quality Model (RZWQM) response to different N management strategies and then used the tested model with observed weather data from 1961– 2003 to quantify long-term effects on corn (Zea mays L.) yield and flow weighted nitrate-N concentration in subsurface “tile”...

Accurate maps of subsurface tile drainage lines are needed for agronomic and environmental research studies the maintenance current systems. In this study, at Purdue University Agronomy Center Research Education near West Lafayette, Indiana were located using a combination visual aerial photo interpretation, expert knowledge, paper construction drawings. The mapping accuracy was assessed 27 loc...

An accurate and management sensitive simulation model for tile-drained Midwestern soils is needed to optimize the use of agricultural management practices (e.g., winter cover crops) to reduce nitrate leaching without adversely affecting corn yield. Our objectives were to enhance the Agricultural Production Systems Simulator (APSIM) for tile drainage, test the modified model for several manageme...

Quantitative estimates of denitrification are needed in designing artificial wetlands to optimize nitrate (NOj-) removal. Acetylene blockage and ~SN-tracer methods were employed to quantify denitriflcation in constructed wetlands receiving agricultural tile drainage, using plastic tubes to enclose in situ mesocosms. Estimates were also made through NO;disappearance from mesocosm water columns. ...

Flowpathways and source water connectivity dynamics are widely recognized to affect tile-drainage quality. In this study, we developed evaluated a framework that couples event-based hydrograph recession specific conductance end-member mixing analysis (SC-EMMA) provide more robust for quantifying both flow pathway of drainage in tile-drained landscapes. High-frequency (30-min) conductivity data ...

SWAT (Soil and Water Assessment Tool) is a watershed model that has been incorporated into USEPA’s modeling framework called BASINS used for total maximum daily load (TMDL) analysis. It is thus important that SWAT realistically simulate tile flow and pothole landscapes that are common in much of the Corn Belt and Great Lakes states. In this study, SWAT was modified to simulate water table dynam...

Denitrification, the microbial reduction of nitrate (NO3) in groundwater, has three requirements: limited oxygen, bacteria capable of mediating the reaction, and electron donors for the bacteria to use in the redox reactions. The critical factor for aquifer denitrification is the concentrations of electron donors. Without an adequate supply of electron donors, bacteria cannot reduce concentrati...

Long-term applications of organic or inorganic sources of N to croplands can increase the leaching potential of nitrate– nitrogen (NO3–N) for soils underlain by subsurface drainage ‘‘tile’’ network. A field study was conducted for 6 years (1993– 1998) to determine the effects of liquid swine manure and urea ammonium nitrate (UAN) solution fertilizer applications on NO3–N concentrations and NO3–...

Tile drainage water from agricultural fields commonly exceeds environmental guidelines for phosphorus (P) in rivers and streams. The loss of P through artificial drainage is spatially and temporally variable, and is related to local factors. This study characterizes variability in total P (TP) and soluble reactive P (SRP) concentrations in weekly drainage samples from 39 agricultural fields in ...