Evaluating Dust Abatement Potential of Stocking Density Manipulation at Open-Lot Cattle Feedyards
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Evaluating the Dust Abatement Potential of Stocking Density Manipulation at Open-Lot Cattle Feedyards K. Jack Bush, Research Associate, Texas A&M AgriLife Research; Brent W. Auvermann, Professor of Agricultural Engineering, Texas A&M AgriLife Research; Gary W. Marek, Postdoctoral Research Associate, Texas A&M AgriLife Research; Kevin Heflin, Extension Associate, Texas A&M AgriLife Research; Sharon Preece, Senior Research Associate, Texas A&M AgriLife Research.
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For more: http://www.extension.org/67576 Fugitive dust abatement from cattle feedlots continues to be an area of concern for feedlot managers and regulators. Currently, water application and manure harvesting are Beneficial Management Practices (BMP) commonly used for dust abatement. Stocking density manipulation could be used as an additional BMP. The moisture and compaction dynamics of an open-lot corral surface in a cattle feedyard depend strongly on the spatial density at which the animals are stocked. Because the moisture content and bulk density of the corral surface are directly related to its intrinsic dust susceptibility (Auvermann, 2003; Razote et al., 2006), emission of fugitive dust from a feedyard surface should be sensitive to changes in stocking density and the moisture- dynamics changes that it induces. Path averaged airborne dust concentrations were measured upwind and downwind of feedyard pens using an optical particle sizer OPS (model 3330, TSI inc., Shoreview, MN) and an aerosol monitor (model DUSTRAK II 8530, TSI inc., Shoreview, MN) mounted on mobile sampling platforms. Feedlot pens were stocked at two densities, 718 (control) and 1,435 hd ha -1. Doubled stocking density was achieved in two different ways, by (A) confining cattle to half the pen area using electric cross-fencing and (B) doubling the number of cattle in the pens. We will report differences in dust concentrations and corral surface conditions associated with pen stocking density.
Transcript of Evaluating Dust Abatement Potential of Stocking Density Manipulation at Open-Lot Cattle Feedyards
Evaluating the Dust Abatement Potential of Stocking Density Manipulation at Open-Lot Cattle FeedyardsK. Jack Bush, Research Associate, Texas A&M AgriLife Research; Brent W. Auvermann, Professor of Agricultural Engineering, Texas A&M AgriLife Research; Gary W. Marek, Postdoctoral Research Associate, Texas A&M AgriLife Research; Kevin Heflin, Extension Associate, Texas A&M AgriLife Research; Sharon Preece, Senior Research Associate, Texas A&M AgriLife Research.
Feedyard Dust◉ Annoyance◉ Health Hazard◉ Traffic Hazard
Introduction
Manure Harvest Water application
◉ Sprinkler, Water Truck etc. Chemical Amendments
◉ Oils and Resins Feed Management
◉ Feed Timing◉ Increased Lipids
Stocking Density◉ Low Cost Alternative?
Dust Abatement Measures
Feedyard Pens Blocked◉ Control Pens = Normal Stocking Density of 150 ft2/hd◉ Treatment 1 = Double Stocking Density of 75 ft2/hd by 50%
Reduction in Pen Area◉ Treatment 2 = Double Stocking Density of 75 ft2/hd by 100%
increase in # of Cattle
Methods
Stocking Density Treatments
Mobile sampling platforms provide path averaged airborne dust concentrations
2 Samplers used◉ Optical Particle Sizer (OPS) (model 3330, TSI inc., Shoreview,
MN) ◉ Aerosol Monitor (model DUSTRAK II 8530, TSI inc., Shoreview,
MN) Sampler Inlet set at 22 inches above ground Collocated with GPS Device Cruise Control Fabricated to limit speed to 1mph
PM10 Sampling
ATV Outfitted with OPS and GPS Devices
Sampling Platforms
UTV Outfitted with DUSTRAK II and GPS
Sampling Platforms
OPS Driven in Loop Downwind of J pens
Dustrak Driven in Loop Downwind of K pens
Each loop takes 30 Minutes
15 Minutes on Downwind 15 Minutes on Upwind
Sampler Path
Southerly Winds Dry Conditions Sample in the evening to take advantage of the “Evening
Dust Peak” when dust concentrations are highest
PM10 Sampling Criteria
Weather Station recorded surface data for entire sampling period
Weather
AERMOD (Lakes Environmental, Waterloo, ON)◉ EPA Regulatory model
◉ Used to Calculate PM10 Emission Rates (mg/m2 –sec) and Emission Factors (kg/1000 hd-day) using a standard scaling approach
Dispersion Modeling
Corral Surface Condition Description
ALittle to no uncompacted manure visible on the corral surface; hard and smooth, may be moist to dry
BWell compacted surface easily visible; small clods of uncompacted manure present
CCompacted surface sparsely visible, nearly covered with small manure clods
DCompacted layer not visible, completely covered with dry, uncompacted manure in chunks and/or clods
ECompletely covered with <1” of finely textured, dry, uncompacted manure “fluff”
FCompletely covered with >1” of finely textured, dry, uncompacted manure “fluff”
WWet; sloppy and/or uneven surface >25% of corral area
Pen Surface Assessment
B
Pen Surface Assessment
C
Pen Surface Assessment
E
Pen Surface Assessment
Results
Results
J Row K+J Rows0
100
200
300
400
500
600
700
Average Downwind PM10 Concentrations
Control Treatment 1Treatment 2
Avera
ge D
ow
nw
ind P
M10 C
oncentr
ati
on (
mg/m
3)
Results
J Row K+J Rows0
5
10
15
20
25
30
35
40
45
50
Average PM10 Emission Flux
Control Treatment 1Treatment 2
Avera
ge C
alc
ula
ted E
mis
sio
n F
lux (
mg/m
2-s
ec)
Results
J Row K+J Rows0
10
20
30
40
50
60
Average PM10 Emission Factor
Control Treatment 1Treatment 2
Avera
ge C
alc
ula
ted E
mis
sio
n F
acto
r (K
g/1
000 h
d-
day)
Post Hoc Tukey Test (a=0.05)
J Row (OPS) K+J Row (DUSTRAK II)
Concentration Emission Flux Concentration Emission Flux
Control - T1 * p = 0.002 X * p=0.001 * p=0.010
Control- T2 X X * p=0.001 *p=0.004
T1-T2 * p = 0.002 X X X
Results
ANOVA (a=0.05)
J Row (OPS) K+J Row (DUSTRAK II)
Concentration Emission Flux Concentration Emission Flux
* p=0.003 X * P= 0.001 * P=0.002
Results
WA
BC
DE
F
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Corral Surface Assessment Score Frequency
Control PensDouble Stocked Pens
Surface Condition Score
% O
f Tim
es S
core
Used
Boundary Between Control and Treatment Blocks
Dust Plume
Discussion
PM10 Emissions reduced◉ Emission Flux◉ Emission Factor
Increased Stocking Density Changes Feedyard Surface◉ Compacting Manure layer◉ Increasing Moisture Content
JBS Five Rivers
Acknowledgements
J Row (OPS Measured) K Row (DUSTRAK II Measured)Avg 1hr Mass Concentration (mg/m3)
Avg Emission Flux (mg/m2-sec)
Emission Factor (kg/1000 hd-day)
Avg 1hr Mass Concentration (mg/m3)
Avg Emission Flux (mg/m2-sec)
Emission Factor (kg/1000 hd-day)
Control 632.16 45.15 54.33 339.8 42.16 50.73
Treatment 1 60.56 21.44 12.9 64.99 11.7 7.04
Treatment 2 292.85 21.89 13.18 52 7.56 4.55
Results
