ARS | Publication request: NUTRIENT ASSIMILATION IN AGRICUTLURAL DRAINAGE DITCHES: THE ROLE OF PLANTS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 29, 2004
Publication Date: July 7, 2004
Citation: Kroger, R., Holland, M.M., Moore, M.T., Cooper, C.M. 2004. Nutrient assimilation in agricultural drainage ditches: The role of plants [abstract]. INTERCOL (International Wetlands Conference). p.167.

Technical Abstract: Wetlands, situated at the interface between source and receiving waters, have the potential to mitigate nutrient pollution. Drainage ditches, as integral components of the agricultural landscape, remove surface runoff and act as major conduits of nutrients from agricultural lands to receiving waters. Numerous studies have highlighted the effectiveness of wetlands; however, very little research has gone into investigating the utilization of agricultural landscape features (e.g. drainage ditches) for mitigation of nutrients associated with storm water runoff. This study describes the assimilation of nutrients within drainage ditches under variable hydrological regimes in fields planted to conventional tillage cotton, a major agricultural commodity in the Mississippi River Delta. Preliminary nutrient analyses of vegetation in simulated ditches suggests that plants exposed to elevated nutrient levels actively assimilate nutrients. Two species of native plants, Leersia oryzoides and Paspalum urvillei, were exposed to elevated nutrient runoff for a period of four months. Above and below ground biomass of both species had significantly higher concentrations of nitrate (p>0.05) and orthophosphate (p<0.001) when compared to a control. Decomposition experiments of Leersia oryzoides in a greenhouse environment are being conducted throughout the summer of 2004. It is hypothesized that the experiment will show similar nitrate (mg/L) and phosphorus (mg/L) levels in the water column as compared to the plant and control vegetation. Thus, wetland plant nutrient assimilation of non-point source pollution would be negated in areas where extreme seasonality resulted in a release of nutrients back into the landscape as a result of plant senescence.