2002 Annual Report
Research
Feasibility of Controlled Drainage in Southern Minnesota
Gary Sands, Assistant Professor
Bradley Hansen, Assistant Scientist
Lowell Busman, Extension Educator, Southern Research and Outreach Center,
Lamberton, Minn.
David Mulla, Professor, Soil, Water, and Climate
Steven Taff, Associate Professor, Applied Economics
Funding Source
University of Minnesota Water Resources Center; University of Minnesota
Graduate School; Minnesota Agricultural Experiment Station; Minnesota
Land Improvement Contractors of America; Prinsco, Inc.; Advanced Drainage
Systems, Inc.; Hancor; Hawkeye Tile; Agri-Drain Corp.
Objective
The objectives of this project are to determine the water quality, hydrologic,
and agronomic impacts of controlled drainage and to determine economic
and technical feasibility of controlled drainage for southern Minnesota.
Project Description
Controlled drainage is a management tool that has been used effectively
in other states and climatic regions to mitigate nitrate losses from tile
drainage systems. This project seeks to determine the feasibility and
effectiveness of controlled drainage in Minnesota by investigating the
water quality, hydrologic, and agronomic impacts of this practice. Four
0.5-acre plots were established in 2000 with drainage systems and structures
to control outlet water levels. Two of the four plots have managed outlets,
while the other two have freely draining outlets. Surface and subsurface
flow and nitrate-nitrogen concentration are measured and compared between
the controlled and uncontrolled plots and are also compared to undrained
conditions. Other measurements include water table elevations. Field data
are being used to calibrate and validate a computer drainage model to
simulate performance of the controlled drainage systems over a wide range
of soils and outlet management scenarios.
Results
Data from 2001 and 2002 indicate that controlled drainage can reduce the volume of drainage, and hence, the nitrate loss, from drained fields. Computer simulation is being undertaken to investigate the nature of these effects over longer climatic records and other soil types.