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ItemPhosphorus, sediment, and e. Coli loads in unfenced streams of the Georgia Piedmont, USA(Georgia Institute of Technology, 2005-04) Byers, Harris L. ; Cabrera, Miguel L. ; Matthews, Monte K. ; Franklin, Dorcas H. ; Andrae, John G. ; Radcliffe, David E. ; McCann, Mark A. ; Kuykendall, Holli A. ; Hoveland, Carl S. ; Calvert, Vaughn H., IIContamination of unfenced streams with phosphorus, sediments, and pathogenic bacteria from cattle activity may be affected by the availability of shade and alternative water sources. The objectives of this study were to evaluate water quality in two streams draining tall fescue/ bermudagrass pastures with different shade distributions, and to quantify the effects of alternative water sources on stream water quality. Loads of DRP, TP, and TSS were measured during storm flow, and loads of DRP, TP, TSS, and E.coli were measured every 14 d during base flow in two streams located in the Piedmont region of Georgia. Our results showed that grazing cattle in pastures with unfenced streams contributed significant loads of DRP, TP, TSS, and E. coli to surface waters (p<0.01). Although storm flow was similar in both streams, loads of DRP, TP, and TSS were larger (p< 0.08) in the pasture with the smaller amount of non-riparian shade. Water trough availability significantly decreased (p< 0.08) base flow loads of TSS and E. coli in both streams. Our results indicate that possible BMPs to reduce P, sediment, and E. coli contamination from beef-cattle-grazed pastures may be to develop or encourage non-riparian shade and to provide cattle with an alternative water supply away from the stream.
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ItemThe Effects of Stream Fencing and Water Troughs on Cattle Movement Patterns and Stream Water Quality(Georgia Institute of Technology, 2003-04) Matthews, Monte K. ; Cabrera, Miguel L. ; Franklin, Dorcas H. ; Radcliffe, David E. ; Andrae, John G. ; Calvert, Vaughn H., IIInformation about cattle impact on streams is limited in the southeastern United States. This study is being conducted to determine the effects of stream fencing and use of water troughs on stream water quality in the Georgia Piedmont. Base flow and storm flow samples are taken and analyzed for N, P, E. coli, total sediments, turbidity, dissolved oxygen, and temperature. Global Positioning System collars are used to track cattle and determine the amount of time spent within the stream riparian area. Results from the first year of the study showed that the amount of time cattle spent in riparian areas (over 10%) was positively correlated with daily maximum air temperature (r2 =0.92). Additional results reveal that the concentration of E. coli in base flow samples was higher in unfenced than in fenced streams, and also showed a positive relationship with the time cattle spent in riparian areas. Maximum dissolved reactive P concentrations in storm flow were higher in unfenced than in fenced streams. Removing water troughs from the pasture resulted in an immediate increase in the amount of time cattle spent near the streams.
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ItemWatershed model sensitivity to bacteria parameters(Georgia Institute of Technology, 2003-04) Radcliffe, David E. ; Matthews, Monte ; Cabrera, Miguel L.Watershed-scale models can be used to determine the pollutant daily load in TMDL streams, or to test the effect of different scenarios for reducing bacterial load. HSPF (Hydrological Simulation Program – FORTRAN ) is a watershed-scale model distributed as part of the EPA BASINS system. EPA has also developed a Bacterial Indicator Tool for calculating the effect of livestock and septic systems on the bacterial parameters required by HSPF. We used HSPF and the Bacterial Indicator Tool to predict stream flow and FC concentrations in the Little River watershed of the Upper Oconee River basin and test for model sensitivity to bacteria parameters. We calibrated flow and FC concentrations using data from a USGS gaging station at the Highway 16 crossing near Eatonton, GA. The bacteria samples were collected during the period 1990 to 1994. We tested the sensitivity of the model predictions of FC to bacteria parameters by doubling the values of the parameters and calculating the root mean square change in predicted FC concentration. The most sensitive parameters were (in order of decreasing sensitivity): number of beef cattle, number of dairy cattle, time cattle spend in stream, and in-stream first-order decay rate.
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ItemNitrogen and Phosphorus Losses from No-till Cotton Fertilized with Poultry Litter in the Southern Piedmont(Georgia Institute of Technology, 2001-03) Endale, Dinku M. ; Cabrera, Miguel L. ; Radcliffe, David E. ; Steiner, Jean L.Adoption of conservation tillage and use of poultry litter as fertilizer in major crops is increasing in the southeastern USA. The water quality impact of these alternative cropping methods needs investigation. In a study near Watkinsville, GA, nitrate loss through drainage was similar between no-till (NT) and conventional tillage (CT) cotton (mean 8.9 vs 8.2 kg ha⁻¹). Cotton fertilized with poultry litter (PL) had higher nitrate loss than that fertilized with ammonium nitrate as conventional fertilizer (CF) (10.3 vs 6.5 kg ha⁻¹). Peak nitrate concentrations reached 30 mg L⁻¹ from CT and 15 mg L⁻¹ from NT. Cotton under PL had about 5 mgL⁻¹ higher peak concentration than CF cotton. Losses of dissolved reactive phosphorus in runoff were: 0.24, 0.25, 0.45 and 0.72 kg ha⁻¹ respectively, for CTCF, CTPL, NTCF and NTPL. There was 48% more total runoff from CT than NT.
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ItemAWARE Team Activities in Georgia(Georgia Institute of Technology, 1999-03) Risse, L. Mark ; Radcliffe, David E. ; Harris, Glen ; Newton, G. Larry ; Worley, John ; Cabrera, Miguel L.This paper will discuss the development of the AWARE (Animal Waste Awareness in Research in Extension) team and some of its recent activities. It will cover the goals of the team and how it functions to obtain these goals. It will also discuss some of the tools the team uses including the webpage, listserve, and meetings and discuss how they are helping people throughout the state with information exchange on animal waste management issues. It will also discuss some of the AWARE teams past activities and plans for future activities.
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ItemDifferences of Soil Water Use, Lint and Biomass Yield in No-till and Conventionally Tilled Cotton in the Southern Piedmont(Georgia Institute of Technology, 1999-03) Endale, Dinku M. ; Radcliffe, David E. ; Steiner, Jean L. ; Cabrera, Miguel L. ; McCracken, D. V. ; Vencill, B. V. ; Lhor, L. ; Schomberg, H. H.The southeast, despite its abundant rainfall, suffers short-term summer droughts with detrimental effect on crop yield. No-till production systems provide added insurance against such conditions by improving infiltration, and conserving moisture in drought-prone soils. In three years of experiment near Watkinsville, GA, no-till cotton treatments maintained higher soil moisture content, more vegetative growth and higher lint yield than conventional tillage treatments. A combination of no-till and poultry litter treatments did even better compared to conventional tillage and conventional fertilizer treatments.
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ItemN and P Edge-of-field Losses from Poultry Litter Applications(Georgia Institute of Technology, 1997-03) Vervoort, R. W. ; Radcliffe, David E. ; Cabrera, Miguel L. ; Latimore, M., Jr.Excess application of poultry litter may cause pollution of surface and ground water with Nitrogen (N) and Phosphorus (P). Composting poultry litter could reduce the risk of pollution by creating more stable organic components. Three rates of poultry litter and compost (10 Mg he litter, 20 Mg he litter and 10 Mg he litter combined with 50 Mg ha' compost) to three watersheds under pasture. The watersheds were monitored for surface and subsurface flow. Nitrate concentrations in subsurface flow did not exceed the U.S. Environmental Protection Agency drinking water standard of 10 mg Soluble P concentrations in runoff were high, reaching a maximum of 8.5 mg L4 under the compost treatment. Concentrations of P in soil in the top 15 cm increased dramatically under the compost treatment which creates a high potential for future runoff of P. Total losses of N and P were low, mainly due to few runoff and subsurface events.