Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

Abstract

Drainage water management is a conservation practice that has the potential to reduce drainage outflow and nitrate (NO 3 ) loss from agricultural fields while maintaining or improving crop yields. The goal of this study was to quantify the impact of drainage water management on drain flow, NO 3 concentration, and NO 3 load from subsurface drainage on two farms in Indiana. Paired field studies were conducted following the paired watershed statistical approach modified to accommodate autocorrelation. Annual NO 3 load reductions ranged from 15% to 31%, with an overall reduction of 18% to 23% over the 2-year period, resulting from reductions in both flow and NO 3 concentration. Although the study revealed weaknesses in using the paired statistical approach for a dynamic practice like drainage water management, the results of this study support the use of drainage water management as a conservation practice and provide information for decision-makers about the level of benefits that can be anticipated.

Drainage water management

“…In some cases (Jaynes 2012;Helmers et al 2012), the demonstration sites were established consistent with a field research approach, where the effect of DWM could be compared to conventional drainage in well-instrumented, field-scale, replicated plots. In others (Cooke and Verma 2012;Ghane et al 2012;Adeuya et al 2012), paired DWM and conventionally drained sites were established on farmer-operated, production-scale fields, located on a range of soils and conditions across a wide region of a state. There are advantages and disadvantages to both approaches.…”

Effects of Subsurface Drainage Systems on Water and Nitrogen Footprints Simulated with RZWQM2

“…This limitation was highlighted in a long-term simulation across the Midwest region, in which a controlled-outlet system was found to be most effective in southern areas of the Midwest, such as Missouri, Illinois, Indiana, and Ohio (reductions of 35.8 to 46.3 kg N ha ), which was mostly attributed to differences in the timing of precipitation and drainage (Thorp et al, 2008). In west-central Indiana, DRAINMOD modeling by Ale et al (2010) showed that the majority (>80%) of N loss reduction with DWM occurred during the non-growing season (November through April), which is also typically when the majority of annual precipitation and drainage occurs (Adeuya et al, 2012). However, in regions similar to southeast Iowa, the timing of the majority of annual precipitation (50%) and drainage (70%) (April, May, and June) generally coincides with the release of drainage water through the control structure to allow for spring field activities (Helmers et al, 2005;Thorp et al, 2008).…”

Drainage Water Storage for Improved Resiliency and Environmental Performance of Agricultural Landscapes

“…Unlike conventional drainage systems that remove excess water to the design drain depth whenever it occurs, controlled drainage stores water by increasing the retention time of water in the soil profile thereby reducing annual drainage volumes. Controlled drainage has been shown to be effective in reducing the outflow of water and nitrate-nitrogen (nitrate-N) from drainage systems (Adeuya et al, 2012;Cooke and Verma, 2012;Helmers et al, 2012;Jaynes, 2012 …”