PT  - JOURNAL ARTICLE
AU  - Jeffrey S. Strock
AU  - Curtis J. Dell
AU  - John P. Schmidt
TI  - Managing natural processes in drainage ditches for nonpoint source nitrogen control
DP  - 2007 Jul 01
TA  - Journal of Soil and Water Conservation
PG  - 188--196
VI  - 62
IP  - 4
4099  - http://www.jswconline.org/content/62/4/188.short
4100  - http://www.jswconline.org/content/62/4/188.full
AB  - In watersheds dominated by agriculture, artificial drainage systems can efficiently and quickly transport excess water from agricultural soils. The application of more nitrogen (N) than a crop uses creates a surplus in the soil and increases the risk of N loss to the environment. We examine issues associated with agricultural N use, N transfer from artificially drained agricultural land to drainage ditches, N cycling within ditches, and options for management. Watercourses in agricultural watersheds often have high concentrations of N and are effectively N saturated. Numerous processes are involved in N cycling dynamics and transport pathways in aquatic ecosystems including N mineralization, nitrification, and denitrification. Flow control structures can lower N losses related to artificial drainage by increasing water retention time and allowing greater N removal. An ongoing study in Minnesota compares the impact of flow control structures on N losses from paired ditches with and without flow control. During the first year of observation, results were mixed, with lower N concentrations in nonstorm event samples from the ditch with the flow control structure, but no significant difference in annual total N load between the two ditches. Appropriate management of drainage ditches represents a potential opportunity to remove biologically available forms of N from drainage water through a combination of physical and biogeochemical processes.