USING CONTROLLED DRAINAGE TO REDUCE TOTAL ANNUAL LOADS OF NITRATE-NITROGEN AND PHOSPHATE-PHOSPHORUS FROM SUBSURFACE DRAINAGE WATER FROM CROPLAND
Agronomy & Pest Management
Wm. Bruce Clevenger
Associate Professor and Field Specialist, Farm Management
Ohio State University Extension
Napoleon
Abstract
Conventional subsurface drainage has many documented benefits such as removing excess soil water, reducing surface runoff, and reducing soil erosion. However, conventional subsurface drainage has a few negative consequences such as increasing peak discharge, increase nitrate-nitrogen (N-NO3) exports down stream and increase N-NO3 deeper into the soil profile. Midwestern fresh water streams, rivers and lakes can be impaired by high levels of soluble nutrients such as N-NO3 and phosphate-phosphorus (P-PO4). Two Ohio research studies will be shared to discuss the dynamics between cropland applied nutrients, soluble nutrient concentrations in drainage water and the total annual load of nutrients. The first study was completed at the Ohio Agriculture Research Experiment Northwest Station and primarily measured N-NO3 concentrations and total annual flow volume. Results indicate that applying controlled drainage to the outlet has a significant reduction in the annual loading of N-NO3 at the outlet. The second study is on-going at the Defiance Agricultural Research Association Site in Defiance County, OH. The research goal is to document the water quality and crop yield differences between controlled subsurface drainage verses free subsurface drainage. During 2008 through 2010, N-NO3 and P-PO4 drainage water concentrations were not significantly different comparing controlled drainage and free drainage. N-NO3 and P-PO4 drainage water concentrations did increase significantly in all plots as a result of field applied fertilizer applications. Implication: Production agriculture must control the total annual water flow leaving the farm to have a positive impact on total annual load of impairing nutrients.
Authors: Clevenger, W. B., Allred, B.J.
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Clevenger, W. B. Assistant Professor And Extension Educator, Ohio State University Extension, Ohio, 43512
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Allred, B.J. Adjunct Assistant Professor, Ohio State Univeristy, Ohio, 43210