The full proceedings paper is at: http://www.extension.org/72783 A vegetative treatment area (VTA), as defined by USDA-NRCS, is a “vegetative area composed of perennial grass or forages used for the treatment of runoff from an open lot production system or other process waters”. VTA’s are typically part of a vegetative treatment system (VTS) that includes additional components to remove solids, such as a settling or vegetative infiltration basin. There have been numerous studies, both modeling and field, related to the design and evaluation of VTS’s used to treat animal feeding operation (AFO) runoff; however, none of these have studies evaluated the effectiveness of VTA’s receiving direct runoff from small swine operations during natural rainfall events. Is it possible that a sufficiently sized VTA alone can effectively treat direct runoff from small swine AFO’s during daily operation? This project aims to answer that question and evaluate the effectiveness of VTA’s as a practical and cost-effective alternative wastewater management option to protect surface water quality on small swine facilities. Three locations were established in 2012 at small swine AFO’s in central Texas. In each location, sampling sites were installed to monitor runoff water quantity and quality at the inlet and outlet of the VTA and a nearby control area. Initial data show that the VTA’s provided substantial treatment of the swine facility runoff in terms of reduced nutrient concentrations, but VTA runoff was still higher in nutrients than the control site. The preliminary data highlighted the importance of solids management and year-round vegetation. Hopefully, as these VTA’s become better established, the increased capacity for infiltration and plant nutrient uptake will be reflected in the soil and runoff data.

1. Kori D. Higgs
Master of Science
Dr. Patricia Smith, Committee Chair
Dr. Daren Harmel, Committee Co-Chair
Dr. Kevin Wagner, Committee Member

2. Background
 Small swine operations
 70-75% of operations nationwide are “small” (1-99 head)
 Need practical, low-cost waste management option to protect
water quality and avoid potential regulation and litigation
 Texas Pork Producers Association, Texas State Soil and Water
Conservation Board shared this concern and need for research.

3. Vegetated Treatment Areas
 Vegetative treatment area (VTA) - vegetative area
composed of perennial grass or forages used for the
treatment of runoff from an open lot production system or
other process waters (USDA-NRCS, 2006)
 Typically part of a vegetated treatment system (VTS)
including solids pre-treatment
 Previous research mostly on cattle AFOs
 VTSs have been found to:
 Reduce total N and P concentrations by up to 80%
 Reduce nutrient loads by 60-99%
 Retain 85-100% of runoff

4. Research Objectives
 Can sufficiently sized, standalone VTA effectively treat
runoff from small swine AFO?
 Research objectives
 Evaluate the efficiency of a standalone VTA at removing N
and P from swine facility runoff
 Compare the VTA runoff to local ambient water quality

5. VTA Design and Setup
 Key components (Koelsch et al., 2006).
 Pre-treatment
 Sheet flow
 Siting
 Sizing
 Source/Treatment Area
 Discharge control
 Established three VTAs with:
 Perennial vegetative cover and hay removal
 No additional fertilizer
 Each location also had rural/residential area as control

7. Bell County
VTA In
Source Area (ha): 0.15
VTA area (ha): 0.34
Control area (ha): 0.48
VTA area/Source area ratio: 2.3
Avg. # animals: 50
Slope: 2.0%
Vegetation: Coastal Bermuda/Oats VTA Out

8. Brazos County
VTA In and pens
VTA In and VTA Out
Control
Source Area (ha): 0.10
VTA area (ha): 0.40
Control area (ha): 1.2
VTA area/Source area ratio: 4.0
Avg. # animals: 20
Slope: 2.5%
Vegetation: Native pasture/Oats

9. Robertson County
VTA In
VTA OutVTA In, VTA Out, and Control
Source Area (ha): 0.03
VTA area (ha): 0.11
Control area (ha): 0.16
VTA area/Source area ratio: 3.7
Avg. # animals: 8
Slope: 1.6%
Vegetation: Native pasture/Oats

10. Data Collection
 Water quality monitoring January 2013 - December 2014
 Automated, flow-weighted, composite sampling
 Event mean concentration (EMC)
 Load = EMC x flow volume
 Analyzed for:
 NO3-N, NH4-N, PO4-P, TP, TN
 Soil sampled in April, October each year
 0-15 cm and 15-30 cm depths
 Analyzed for:
 Inorganic P and N

11. Water Quality Results
 VTAs reduced:
 runoff volume by 17-55%
 nutrient concentrations by 23-91%
 loads by 50-96%
 **some NO3-N concentrations and loads increased.**
Site
Median PO4-P
(VTA in)
Median PO4-P
(VTA out)
Median PO4-P
(Control)
Bell 16.1 2.4 0.8
Brazos 15.9 3.1 0.4
Robertson 0.4 0.2 0.1

12. Soil Nutrient Results

13. Soil Nutrient Results

14. Summary of Results
 Runoff N, P
 VTA in > VTA out
 Soil N, P
 Little/no buildup
 So did the VTA’s work???
 VTA out > control

15. Conclusions
 Two years of data showed:
 significant N, P reductions between VTA in and VTA out
 Little/no buildup of soil N, P
 These results highlight the importance of:
 solids management
 perennial grass maintenance and subsequent haying/removal
 consideration of nutrient loads relative to VTA area.
 Increased treatment area potentially makes up for lack of
solids pretreatment.
 VTA is potentially effective waste management option for
small swine facilities.

16. THANK YOU
Daren Harmel
254-541-1875
daren.harmel@ars.usda.gov