Location: Water Quality and Ecology Research2016 Annual Report
1. Enhanced watershed management planning technology available. A new version (v5.44) of the Annualized Agricultural Non-Point Source (AnnAGNPS) watershed planning tool was released with enhanced gully, wetland and riparian buffer components. These components are critical in development of integrated conservation management practice watershed plans. It provides watershed conservation managers with technology to implement the efficient placement of practices with minimum utilization of resources.
2. Mowing vegetation in ditches still allows for nutrient mitigation. Small-scale field trials compared the nitrogen and phosphorus concentrations in runoff through vegetated agricultural drainage ditches that had been mowed and an equal number that were left undisturbed. No significant differences in nutrient concentrations between ditch type (mowed vs. undisturbed) were noted. Results suggest farmers can maintain their ditches through mowing, an important aesthetic and pest control feature, while still providing nutrient reduction capacities. This provides beneficial management strategies to be utilized by farmers and landowners in maintaining vegetated drainage ditches.
3. Nutrient mitigation best achieved with aquatic plant mixtures in wetlands and ditches. Mesocosm experiments compared the nitrogen and phosphorus retention capability of six different aquatic plants against each other and against an unvegetated control over two summers. Cattails (Typha latifolia) had significantly better phosphorus retention than the control and other plants during both summer experiments. Other aquatic plants had significant nutrient retention in the first summer, but results from the second summer were not significant. This research highlights the inherent variability among different aquatic plants used for nutrient uptake. As a result, researchers are now examining different plant mixtures to determine optimum nutrient mitigation. With this increased understanding, farmers and landowners can better design management systems to decrease nutrient input into downstream receiving systems.Keating, M.P., Balachandran, D., Ochs, C.A., Holland, M.M., Lizotte Jr, R.E., Yu, K. 2015. Spatial variation related to hydroloigc patterns and vegetation in greenhouse gas fluxes from the Mississippi Delta agricultural region. Applied Soil Ecology. 98:278-281 DOI: 10.1016/j.apsoil.2015.09.012.