Location: Water Quality and Ecology ResearchTitle: Nutrient mitigation efficiency in agricultural drainage ditches: An influence of landscape properties Author
Submitted to: Bulletin of Environmental Contamination and Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2016
Publication Date: 3/29/2016
Publication URL: http://handle.nal.usda.gov/10113/62594
Citation: Iseyemi, O.O., Farris, J.L., Moore, M.T., Choi, S. 2016. Nutrient mitigation efficiency in agricultural drainage ditches: An influence of landscape properties. Bulletin of Environmental Contamination and Toxicology. 96:750-756. Interpretive Summary: Excess nutrients have been blamed for water quality problems resulting in the hypoxic zone in the Gulf of Mexico and elsewhere. Vegetated drainage ditches are conduits between production agriculture and receiving water bodies. Many landowners prefer to keep their ditch vegetation mowed for both aesthetic and flow reasons. The current study compared mowed ditches to those left unmowed to determine if there were differences in nitrogen and phosphorus reduction in the systems. Nutrient measurements from water samples showed no significant difference between ditches that were mowed or unmowed. This indicates farmers can potentially maintain their ditches through mowing, while still providing nutrient reduction capabilities. Results provide beneficial management strategies which can be utilized by farmers and landowners in maintaining vegetated drainage ditches.
Technical Abstract: Drainage systems are integral parts of the agricultural landscapes and have the ability to intercept nutrient loading from runoff to surface water. This study investigated nutrient removal efficiency within replicated experimental conventional and controlled (with weirs) agricultural drainage ditches during a simulated summer runoff event. Study objectives were to examine the influence of routine mowing of vegetated ditches on nutrient mitigation and to assess spatial transformation of nutrients along ditch length. Both mowed and unmowed ditch treatments decreased NO3 by 79 and 94 % and PO4 by 95 and 98%, respectively, with no significant difference in reduction capacities between the two treatments. This suggests occasional ditch mowing as a management practice would not undermine nutrient mitigation capacity of vegetated drainage ditches. Outcomes from this study indicate proper understanding and manipulation of agricultural ditches landscape properties is vital to improve ditch capacity to mitigate nutrient loads to receiving water.