Irrigation and Drainage
394927 - Clay County Drainage Site: Field Scale Drainage Research in the Minnesota Red River Valley
Wednesday, June 6
4:00 PM - 5:30 PM
Location: Skyway Room
Northwestern Minnesota’s Red River Valley has experienced an increase in the installation of agricultural subsurface drain systems. In this region of silty clay loam soils, drainage tile is installed to remove excess soil water to facilitate earlier agricultural fieldwork and improve soil conditions for crop growth. In 2010, the Minnesota Department of Agriculture re-instrumented and increased monitoring at an existing 155 acre field-scale research site in Clay County, to monitor environmental impacts of surface and subsurface drainage from agricultural fields in the Red River Valley at the field scale. The instrumentation and layout of the site offers an opportunity to address a number of critical water related issues in the Valley. The site includes one surface and six subsurface drainage plots, monitored separately to collect hydrologic, nutrient and sediment characteristics. The first phase of the project (2011-2015) was managed to understand the volume of drainage and range of nutrients lost via agricultural drainage. Results from the first phase show 61% of subsurface drainage occurred in May and June. Annual mean flow weighted nitrate-nitrogen concentrations in subsurface drainage ranged from 3.7 mg/l to 23.7 mg/l, with highest concentrations in June and July. Annual mean flow weighted total phosphorus concentrations ranged from 0.04 mg/l to 0.08 mg/l. The second phase of this project (2016-ongoing) is designed to compare controlled drainage (drainage water management) and conventional drainage. A paired-plot experimental design is being used to determine the effectiveness of controlled drainage on water management and on the reduction of nutrient loss from subsurface drainage. Long term water quality and quantity data from these plots will enhance our understanding of the hydrologic effects of subsurface drainage in the Red River Valley’s agricultural landscape, and help improve water and nutrient management options for subsurface drainage systems.