1a. Objectives (from AD-416)
The Natural Resources Conservation Service (NRCS) and the Agricultural Research Service (ARS) have agreed to work together, as part of the national Conservation Effects Assessment Project (CEAP) initiative to quantify the environmental benefits of conservation practices at the watershed scale. The project plan detailed in this document represents one of 12 ARS CEAP watersheds established under the national CEAP initiative to address conservation and environmental research issues. Objectives of the project are to: 1) develop and implement a data system to organize, document, manipulate, and compile water, soil, management, and socio-economic data for assessment of conservation practices at field, farm, and watershed scales for the Mark Twain Lake watershed; 2) measure and quantify water quality, water quantity, and soil quality effects of conservation practices at the field, farm, and sub-watershed scale for the Mark Twain Lake; and 3) validate models, quantify uncertainties in model output, and conduct analyses with hydrologic models at field, farm, and watershed scales, and develop methodologies and decision support tools for application on watersheds within the Mark Twain Lake watershed.
1b. Approach (from AD-416)
This research will focus on developing tools and techniques to quantify the impact of implementing conservation practices within a watershed in the most economically efficient manner to achieve sustainable and targeted reductions of nutrients, sediment, herbicide, and pathogen loadings to the Salt River/Mark Twain Lake basin. The research encompasses the following approaches: 1) participation in the development of the STEWARDS database; 2) conduct water quality monitoring to characterize the hydrologic balance and nutrient/chemical loading to Mark Twain Lake; 3) conduct studies at field and plot scales to determine the effectiveness of various conservation practices and cropping systems to reduce nutrient, sediment, and herbicide transport; 4) develop a real-time PCR (RT-RCR) method for quantitation of pathogenic water-borne bacterial species; 5) use the SWAT model to evaluate conservation practices and conservation systems abilities to reduce nutrient, sediment, pesticide, and pathogen loadings in agricultural watersheds; and 6) apply the SWAT model to improve surface water quality assessment and planning.
3. Progress Report
In 2010, re-installation of the Salt River monitoring network for a sixth year was completed on schedule with the assistance of Environmental Resources Coalition staff. After this year, the monitoring network will be reduced, but we will continue monitoring data for watersheds with projects funded by the NRCS Mississippi River Basin Initiative. Over the last year, the Cropping Systems Water Quality Research (CSWQR) lab received 1,115 Conservation Effects Assessment Project (CEAP) samples for nutrient, herbicide, and sediment analyses. Other CEAP activities in 2010 included completion of two full years of seasonal data collection for a streambank erosion project at 34 sites located in Crooked and Otter Creek watersheds (both watersheds are located within the Salt River Basin). This project is a collaborative effort with researchers from Iowa State University. Results to date indicate that approximately 50% of the annual in-stream sediment was derived from streambank erosion in these claypan watersheds. This project has also facilitated positive relationships with 17 landowners within the study area. Another of our CEAP-related activity involves identification of vulnerable areas within fields and watersheds that should be targeted for conservation practices. Multiple efforts at developing appropriate metrics and application of simulation or index models for identifying vulnerable areas have been completed this year. Future efforts will focus on delivering these decision support tools to National Resources Conservation Service (NRCS). If sufficient interest is expressed, then these tools will be coded for use in NRCS field offices as decision support aids for targeting conservation practices. CSWQR continued on-going efforts to upload data and metadata to the STEWARDS database. The Precision Agriculture System (PAS) work has been continued under this project, with nearly six years of field data collected. Previous development of a molecular technique for analysis of specific human gut bacteria (Bacterioides sp.) is being retroactively applied to samples collected from 10 sites within the Bonne Femme watershed in which fecal coliform analyses had previously been performed. Preliminary results show high concentrations of this human bacterial indicator species in these streams. Outreach activities in 2010 included completion of a watershed plan for Goodwater Creek, presentation of the streambank erosion results to several (~10) landowners, and multiple interviews and/or press releases related to findings of the streambank erosion project and long-term trends in herbicide transport in Goodwater Creek. Other outreach activities included exhibits by CSWQR at the Missouri Association of Soil and Water Conservation Districts annual meeting, and the Missouri Natural Resources Conference. In addition, two field tours of our CEAP field sites were conducted in conjunction with the Soil and Water Conservation Society meeting (12 participants) and the University of Missouri’s Crop and Disease Injury Clinic (78 participants).
1. Documented dissipation of Sulfamethazine and Tetracycline in the root zone of grass and tree species. Veterinary antibiotics are introduced into the environment through land application of livestock manures. The effect of three grass and one tree species commonly used in vegetative buffers on the degradation of two antibiotics typically used in livestock production, sulfamethazine and tetracycline, was examined. Tetracycline dissipated rapidly under all vegetative treatments, indicating its relative instability in the soil environment. Sulfamethazine, however, was more persistent in soils and degraded most rapidly in the root zone of poplar saplings. The degradation rate was highly correlated to the microbial activity in the poplar root zone, indicating that this plant species supports a microbial community capable of rapidly breaking down sulfamethazine. Thus, use of poplar trees in vegetative buffers adjacent to fields receiving livestock manure applications could help alleviate the transport of antibiotics in the environment.
2. Herbicide transport in surface runoff from a claypan soil: scaling a model from plots to fields. A key challenge in evaluating the effect of various cropping systems on the transport of soil-applied herbicides has been the applicability of plot-scale results to the field scale. In this study, field-scale transport of atrazine and metolachlor measured from two fields and the results compared to those predicted by herbicide transport model developed at the plot-scale. The model developed from plot-scale data reasonably estimated herbicide concentrations at the field scale, particularly for atrazine. Inclusion of temperature and soil moisture into the plot-scale model significantly improved prediction of metolachlor concentrations at the field scale. The study also confirmed, at the field scale, the plot-level finding that atrazine and metolachlor losses were higher when the herbicide was not incorporated. The study showed that the model developed using plot-scale data was generally applicable to predicting herbicide concentrations at the field scale.
Lin, C., Goyne, K.W., Kremer, R.J., Lerch, R.N., Garrett, H.E. 2010. Dissipation of Sulfamethazine and Tetracycline in the Root Zone of Grass and Tree Species. Journal of Environmental Quality. 39:1269-1278.