Submitted to: Society of Wetland Scientists
Publication Type: Abstract only
Publication Acceptance Date: 10/15/2006
Publication Date: 11/1/2006
Citation: Kroger, R., Holland, M.M., Moore, M.T., Cooper, C.M. 2006. Agricultural Drainage Ditches Mitigate N and P Loads as a Function of Hydrological Variability. Society of Wetland Scientists. Abstracts of the South Central Chapter Annual Meeting, Vicksburg, MS. p. 5 Interpretive Summary: Abstract only. Interpretive summary not required.
Technical Abstract: Agricultural activities play a substantial role in non-point pollution of receiving waters. Several efforts to remediate pollution sources include constructed wetlands, buffer strips and best management practices. However, agricultural drainage ditches are primary intercept wetlands that have not been used in this capacity. Drainage ditches are truly forgotten links between agricultural farms and receiving waters, and no research has gone into their nutrient mitigation capabilities. Two primary, surface drainage ditches were monitored for two years to determine: 1) the concentration and load of N and P moving from a no-till cotton farm into the drainage ditch, and 2) determine the mitigation capacity of the drainage ditch for N and P. The loading of inorganic N (for the majority NO3-) and phosphate species into stormflow and surface water within the drainage ditch was a function of fertilizer application rate, the transport characteristics (volume, intensity, duration) as a result of precipitation events, and the respective concentrations of the nutrient species in the transported water. The stage of a respective storm event, the amount of water volume that passes through the ditch, and the respective discharge rate had a large influence on the ability of the agricultural drainage ditch to mitigate the effluent farm N and P load. Surface drainage ditches did mitigate N and P farm effluent before it reached receiving waters. Hydrologically, the capacity of this reduction was a function of variability in precipitation volumes and discharge rates.