Georgia Water Resources Conference

Series

Georgia Water Resources Conference

Permanent Link

https://hdl.handle.net/1853/70886

Series Type

Event Series

Associated Organization(s)

Organizational Unit

Georgia Water Resources Institute

Full item page

Publication Search Results

Now showing 1 - 10 of 20

Knife Aeration to Reduce Concentrations of Sex Hormones in Surface Runoff from Pastures Fertilized with Broiler Litter

(Georgia Institute of Technology, 2011-04) Hassan, Sayed M. ; Rema, John ; Calvert, Vaughn, II ; Cabrera, Miguel L.

Broiler litter contains the naturally-excreted hormones testosterone and 17-β estradiol, which can contaminate surface runoff when litter is applied to pastures. This study was conducted to evaluate the effect of knife aeration of pastures receiving broiler litter on hormone concentrations in surface runoff. Six 0.8-ha paddocks on tall fescue and bermudagrass were fertilized with 5 Mg ha1 in March and November 2008, and in March 2009. Three paddocks were aerated immediately after application and three paddocks were left non-aerated as controls. Surface runoff samples were collected with automated samplers and analyzed for the sex hormones with GC/MS. Knife aeration reduced concentrations of hormones in surface runoff occurring soon after litter application and aeration. These results suggest that knife aeration may be a useful management practice to reduce contamination of surface waters with sex hormones derived from broiler litter.
Mechanical Aeration to Reduce P Export from Manured Grasslands

(Georgia Institute of Technology, 2007-03) Butler, David M. ; Franklin, Dorcas H. ; Cabrera, Miguel L. ; Tasistro, Armando S. ; Xia, Kang

The poultry industry is an important component of agricultural production in the Southern Piedmont of Georgia. Associated manures are typically surface-applied to pastures as a fertilizer for forages. However, this surface application of manures allows phosphorus (P) to accumulate at the soil surface and runoff to become contaminated with P and to transport it to surface waters. As such, a study was conducted to examine the conservation potential of mechanical aeration of grasslands. Mechanical aeration has potential to reduce P transport by partially incorporating applied manures, allowing for more P adsorption by the soil, increasing infiltration by breaking the soil surface, and by slowing runoff flow by increasing the roughness of the landscape. We examined the effects of four aeration treatments (aeration with cores, “no-till” disk aeration perpendicular to the slope, aeration with spikes, and no aeration treatment) on the export of dissolved reactive P (DRP) in surface runoff from grasslands with two nutrient treatments (broiler litter and a control of no manure). Plots (0.75 x 2 m) were established on a Cecil soil series with mixed tall fescue/bermudagrass vegetation on 8 to 12% slopes. Plots were then aerated and manures applied at a rate of 30 kg P ha-1, prior to simulated rainfall at a rate of 75 mm h-1. While aeration had minimal impact on volume of runoff, core aeration decreased DRP loads (P < 0.05) from applied broiler litter by 61%. Given that Cecil soil is common in pastures receiving broiler litter in the Southern Piedmont, these results suggest that core aeration could have a widespread impact on water quality in the Southern Piedmont region.
Phosphorus, 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., II

Contamination 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.
Field evaluation of compost and mulches for erosion control

(Georgia Institute of Technology, 2005-04) Risse, L. Mark ; Faucette, L. Britt ; Gaskin, Julia W. ; Jordan, Carl F. ; Cabrera, Miguel L. ; West, Larry T.

Soil erosion is one of the largest contributors to nonpoint source pollution in Georgia. The use of surface applied organic amendments has been shown to reduce runoff and erosion and improve vegetative establishment on degraded soils such as those common to Georgia. In this study, four types of compost blankets, hydroseed, silt fence, and a bare soil (control) were applied in field test plots. Treatments were seeded with common bermuda grass. Simulated rainfall was applied at an average rate equivalent to a 50 yr one-hour storm event, and runoff samples were collected and analyzed for solids as well as runoff quantity. Three simulated rain events were conducted: immediately after treatment application, at vegetation establishment, and at vegetation maturity. In the short term, compost treatments produced significantly less runoff than the hydroseeded and bare soil plots. All treatments proved better than the control at reducing solids loss. Total solids loads were as much as 350% greater from the hydroseeded plots compared to the composts during the first storm and as much as 36 times greater during the second storm. Vegetative growth and nutrient loss data were also evaluated.
Using the Georgia P-Index to identify high risk management of poultry litter

(Georgia Institute of Technology, 2005-04) Gaskin, Julia W. ; Harris, Keith ; Cabrera, Miguel L. ; Risse, L. Mark

The Georgia P Index was developed as a tool to evaluate the risk of bioavailable P loss in fields under various management practices. We compared the results of the P Index with four years of data from 1.5 m by 4.6 m bermudagrass plots fertilized with poultry litter at 8.9 Mg ha-1 (recommended rate); poultry litter at 17.9 Mg ha-1; composted poultry litter, poultry litter with alum, commercial fertilizer; and a control (no amendments). P Index ratings above 75 indicate high risk where management should be changed. The P Index indicated management changes would be needed for the 17.9 Mg ha-1 treatment during all 4 years, for composted PL during year 4, and for PL with alum during years 3 and 4. The P Index did not indicate management changes were necessary using the recommended rate of 8.9 Mg ha-1 after 4 years of application; however, volume-weighted P concentrations in the 8.9 Mg ha-1 treatment were double the control concentrations during years 3 and 4. The comparison indicates that the P Index does identify high risk management practices under the conditions of this study.
Watershed assessment through ecological research/farmers active in research

(Georgia Institute of Technology, 2003-04) Franklin, Dorcas H. ; Cabrera, Miguel L. ; Steiner, Jean L. ; Risse, Larry A. ; Risse, L. Mark ; Hibbs, Henry E.

Producers in the Southern Piedmont graze and manage their lands in a variety of ways across watersheds and across individual farms. These land management practices may have an impact on the nitrogen (N) and phosphorus (P) concentrations in stream base flow and storm flow. A group of producers, researchers and educators (WATER/FAIR) pulled together to assess stream nutrient concentrations relative to land management practices in two typical Southern Piedmont watersheds. The objective of this paper is to increase awareness of participatory monitoring and of the spatial and temporal distribution of stream nutrients (N & P) at watershed and farm levels. Results showed that dissolved reactive P (DRP) concentrations were highly variable depending on the management system. Stream base flow nitrate concentrations were lower leaving farms than going into farms more than more than 75 percent of the time and were 16 percent lower in 2000 than in 1999. These lower concentrations coming out of farms could suggest that these management systems are not losing nutrients to aquatic systems but rather utilizing them on the farm.
The 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., II

Information 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.
Watershed 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.
Nitrogen 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.
AWARE 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.