Submitted to: Ohio State University Thesis
Publication Type: Other
Publication Acceptance Date: 5/20/2002
Publication Date: 3/20/2002
Citation: ZWIERSCHKE, E.L. TESTING THE ABILITY OF DRAINMOD 5.1 TO SIMULATE THE EFFECT OF WATER TABLE MANAGEMENT PRACTICES ON NITRATE NITROGEN IN DRAINAGE WATER. 2002. THE OHIO STATE UNIVERSITY. 118 p.
Technical Abstract: This project calibrated and validated DRAINMOD 5.1 for prediction of nitrate concentrations in drainage water using measured data from conventional drainage and combined (controlled drainage/sub irrigated) water table management plots. Weather, soil, water and crop data collected at The Ohio State University Piketon Research and Extension Center facility at Piketon, Ohio during 1996 and 1997 were used to calibrate and validate this model. Results indicated that DRAINMOD 5.1 was able to predict daily water table heights within approximately 30 cm for both conventional and combined drainage practices on the Omulga silt loam soil at the Piketon site. DRAINMOD 5.1 did predict annual cumulative nitrate loads adequately for conventional drainage. However, limitations with DRAINMOD 5.1 were experienced when predicting nitrate loads in drainage water from plots with combined water table management. Model predictions for the combined system'consistently overestimated the nitrate loads in drainage water from these plots. It was necessary to alter the input parameters controlling denitrification and mineralization in order to achieve more accurate predictions. Several program modifications to DRAINMOD 5.1 were required during the course of this project. It may, therefore, be possible to use DRAINMOD 5.1 to optimize the amount and timing of field fertilization; field drain spacing; and water table depth to minimize the nitrate loads in drainage water from fields in the Midwest, and enable best management practices to be defined. This could have a significant impact on the nitrate loads in the Mississippi River and cause a subsequent reduction in hypoxia in the Gulf of Mexico.