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Erosion control and storm water quality from straw with PAM, mulch, and compost blankets of varying particle sizes

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Compost,and mulch blankets have been widely used for slope stabilization and erosion control at construction sites; however, the majority of research on these erosion con- trol blankets has failed to meet state or federal specifications for particle size distribution. The primary objective of this study was to determine how blending wood mulch with compost may affect its performance as an erosion control practice relative to a straw blanket with polyacrylamide (PAM). The secondary objective of this study was to determine,if particle size distribution of the organic erosion control blanket affects runoff, erosion, and vegetation establishment. Researchers concluded that the greater percent of compost used in an erosion control blanket, the lower the total runoff and the slower the runoff rate. Compost erosion control blankets retained 80% of the simulated rainfall applied and reduced cumulative storm runoff by 60%, while the wood mulch blankets reduced runoff by 34% and straw with PAM by 27%. Conversely, the greater the percent of mulch used in the erosion control blanket, the lower the sediment and suspended sediment load. However, any combination of compost and mulch reduced runoff volume, runoff rate, and soil loss relative to a straw blanket with polyacrylamide. The average cover management,factor (C factor) for the straw with PAM was 0.189, the compost blanket was 0.065, and the mulch blanket was 0.013. Researchers also concluded that particle size distribution of the compost and mulch blankets was the leading parameter that reduced soil loss and runoff. If particle size distribution specifica- tions are not followed, total soil loss can be four times greater, suspended solids can be five times greater, and turbidity can be eight times greater, relative to blankets that meet particle size distribution specifications. Nitrogen and phosphorus loading from mineral fertilizer used
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404 journal of soil and water conservation
L. Britt Faucette is a research ecologist/director
at Filtrexx International in Decatur, Georgia.
Jason Governo is a senior engineer at Compost
Wizard in Locust Grove, Georgia. Carl F. Jordan
is a senior ecologist at the Institute of Ecology
in Athens, Georgia. B. Graeme Lockaby is a
professor, Honorio F. Carino is a professor, and
Robin Governo is a research associate in the
School of Forestry at Auburn University in
Auburn, Alabama.
Erosion control and storm water quality
from straw with PAM, mulch, and compost
blankets of varying particle sizes
L.B. Faucette, J. Governo, C.F. Jordan, B.G. Lockaby, H.F. Carino, and R. Governo
Abstract: Compost and mulch blankets have been widely used for slope stabilization and
erosion control at construction sites; however, the majority of research on these erosion con-
trol blankets has failed to meet state or federal specifications for particle size distribution. The
primary objective of this study was to determine how blending wood mulch with compost
may affect its performance as an erosion control practice relative to a straw blanket with
polyacrylamide (PAM). The secondary objective of this study was to determine if particle
size distribution of the organic erosion control blanket affects runoff, erosion, and vegetation
establishment. Researchers concluded that the greater percent of compost used in an erosion
control blanket, the lower the total runoff and the slower the runoff rate. Compost erosion
control blankets retained 80% of the simulated rainfall applied and reduced cumulative storm
runoff by 60%, while the wood mulch blankets reduced runoff by 34% and straw with PAM
by 27%. Conversely, the greater the percent of mulch used in the erosion control blanket, the
lower the sediment and suspended sediment load. However, any combination of compost
and mulch reduced runoff volume, runoff rate, and soil loss relative to a straw blanket with
polyacrylamide. The average cover management factor (C factor) for the straw with PAM
was 0.189, the compost blanket was 0.065, and the mulch blanket was 0.013. Researchers
also concluded that particle size distribution of the compost and mulch blankets was the
leading parameter that reduced soil loss and runoff. If particle size distribution specifica-
tions are not followed, total soil loss can be four times greater, suspended solids can be five
times greater, and turbidity can be eight times greater, relative to blankets that meet particle
size distribution specifications. Nitrogen and phosphorus loading from mineral fertilizer used
with conventional straw blankets may lead to increased nutrient loading of receiving surface
water relative to the compost and mulch blankets. The straw blanket with fertilizer increased
total Kjeldahl nitrogen loading by more than 8,000%, the compost blanket increased total
Kjeldahl nitrogen by 340%, and the mulch blanket by 18% relative to the control. Although
the bare soil and mulch blanket treatments did not contribute any soluble phosphorus
(P) to runoff, relative to the compost blanket, the soluble P load from the straw blanket
with PAM was 3,800% greater. Results from this study may be used to revise particle size
specifications for compost erosion control blankets and to help regulators and design profes-
sionals determine which type of erosion control best management practice is best for their
particular application.
Key words: compost blankets—erosion control—straw blankets—storm water—
water quality
Soil loss from both agricultural and non-
agricultural lands in the United States
amounts to over 4 x 109 tons each year due
to erosion (Brady and Weil 1996). Forested
lands lose an average of 0.36 metric t ha-1
yr-1 (1 tn ac-1 yr-1), agriculture loses an aver-
age of 5.5 metric t ha-1 yr-1 (15 tn ac-1 yr-1),
while construction sites average 73.3 metric t
ha-1 yr-1 (200 tn ac-1 yr-1) (Georgia Soil and
Water Conservation Commission 2002).
The most serious problem of erosion occurs
once the sediment leaves the site of origin
and enters surface waters. When eroded sed-
iment is transported from its site of origin to
nearby surface waters it also carries fertilizers,
pesticides, fuels and other contaminants and
substances commonly spilled at construction
sites that readily attach to soil particles (Risse
and Faucette 2001). It is estimated that the
annual cost to society for on-site loss of soil,
nutrients, water and yield reduction due
to soil erosion is over $27 billion per year
(Brady and Weil 1996).
The US Environmental Protection
Agency (USEPA) has declared that sedi-
ment contamination of our surface waters
is the greatest threat to our nation’s water
resources. Surface water that is loaded with
sediments can lead to reduced drainage capac-
ity, increased flooding, decreased aquatic
organism populations, decreased commercial
and recreational fishing catches, clogged and
damaged commercial and industrial irriga-
tion systems, increased expenditures at water
treatment plants to clean the water, and
decreased recreational and aesthetic value of
water resources (Risse and Faucette 2001). It
is estimated that the national cost to society
due to sedimentation of eroded soil is over
$17 billion per year, bringing the total cost
of erosion and sedimentation to society in
the United States to over $44 billion per year
(Brady and Weil 1996).
Soil erosion is considered the largest
contributor to non-point source pollution
in the United States according to the feder-
ally mandated National Pollution Discharge
Elimination System (NPDES) (USEPA
1997), while soil loss rates from construc-
tion sites can be 20 times that of agricultural
lands (USEPA 2000). In 1987, amendments
to the federal Clean Water Act mandated that
construction sites must control storm water,
erosion, and sediment originating from
their site (USEPA 2000). In 1990, NPDES
Phase 1 Rules mandated that all construc-
tion sites over 2 ha (5 ac) were required to
have land-disturbing activity permits and
pollution prevention plans. In 2003, NPDES
Phase II went into effect extending the storm
water pollution prevention plan requirement
to any land disturbing activity over 0.4
ha (1 ac).
Reprinted from the Journal of Soil and Water
Conservation, Volume 62, Number 6. © 2007
by the Soil and Water Conservation Society.
All rights reserved.
405
nov | dec 2007 volume 62, number 6
Runoff and Erosion Control with Organic
Materials. The use of surface applied organic
amendments has been shown to reduce run-
off and erosion (Adams 1966; Meyer et al.
1972; Laflen et al. 1978; Vleeschauwer and
Boodt 1978; Foster et al. 1985). Runoff from
mulched soils can be reduced to only a frac-
tion of that from unmulched soils, thereby
nearly eliminating soil erosion (Meyer 1985;
Meyer et al. 1972; Laflen et al. 1978; Foster et
al. 1985; Epstein et al. 1966). Because of bet-
ter soil contact and reduced susceptibility to
movement from wind or water, mulches are
superior to hay and straw mats (Lyle 1987).
Shredded bark will intercept and dissipate the
energy of raindrops and prevent soil surface
crusting; they also break up overland flow of
runoff and hold more water at the soil sur-
face allowing more water to infiltrate the soil
(Adams 1966; Gorman et al. 2000). Adams
(1966) found that soils covered with mulch
averaged less than 0.9 metric t ha-1 (1 tn ac-1)
soil loss compared to 18.3 metric t ha-1 (20.2
tn ac-1) from uncovered soils during an 21.25
cm (8.5 in) storm event. Meyer et al. (1972)
found on highway construction slopes of
20% and 46 m (150 ft) long during a 6.25 cm
(2.5 in) storm event, wood mulches yielded
less than 4.5 kg ha-1 (5 tn ac-1) soil loss com-
pared to over 90 kg ha-1 (100 tn ac-1) soil loss
from other management practices.
It is important to recognize the advantage
of compost blankets over wood mulches to
prevent erosion on hill slopes because they
have a better ability to support vegetation.
Both can help reduce runoff and soil loss but
mulches can often have a detrimental effect
on plant growth because of nitrogen immo-
bilization (Meyer et al. 1972) while compost
often has a carbon to nitrogen ratio optimum
for plant uptake and can provide a slow release
of nutrients (Maynard 2000; Granberry et al.
2001) that sustains prolonged healthy plant
growth. Both have quality characteristics that
if brought together in the correct blend, will
increase their ability to reduce runoff while
insuring that vegetation is established quickly
to further protect soil from erosion.
The Georgia Department of Transportation
(G DOT) and Georgia Soil and Water
Conservation Commission only require
that straw mats provide 70 to 75% soil
cover (Georgia Soil and Water Conservation
Commission 2002), but Adams (1966) claims
90% cover, relative to bare soil, is needed
for appreciable differences in infiltration
rates. Compost blankets, when applied cor-
rectly, provide nearly 100% surface coverage
(Faucette 2004). Studies by Adams (1966)
and Meyer et al. (1972) found that signifi-
cant rilling can develop under straw mats,
where most soil loss occurs. Similarly, while
synthetic blankets and mats provide ground
cover, they do not make 100% contact with
uneven soil surfaces, as rilling is common
underneath these practices. Compost blankets
are designed and applied to fill uneven spaces
to prevent rilling. Finally, heavier mulch
materials, like compost, are less likely to blow
off slopes in windy conditions, relative to the
light weight of straw mulch, protecting the
soil from wind erosion (Meyer et al. 1972).
While specifications for compost ero-
sion control blankets (ECBs) have been
accepted and reported (table 1) by the Texas
Department of Transportation (TX DOT),
the American Association of State Highway
and Transportation Officials (AASHTO
2003), the USEPA (USEPA 2006), the
Indiana Department of Natural Resources
(IN DNR), the Coalition of Northeast
Governors/Connecticut Department of
Transportation (CONEG), and many
other public agencies, no research has been
conducted to evaluate the most critical
component of the specifications: the particle
size distribution of the compost used to make
the erosion control blanket. Of the 23 com-
post blanket treatments evaluated by Demars
and Long (1998), Glanville et al. (2001),
Kirchhoff et al. (2003) and Faucette (2004),
Faucette et al. (2005) none met any of the
minimum particle size specification require-
ments for compost ECBs; therefore, the
research literature has likely understated their
true performance in the field. Additionally, it
Table 1
Particle size specications for compost erosion control blankets.
Specifying agency Percent pass 50 mm Percent pass 25 mm Percent pass 18 mm Percent pass 6 mm
TX DOT* 95% 65% 65 (16 mm) 50% (9.5 mm)
AASHTO 100% (75 mm) 90% to 100% 65% to 100% 0 to 75%
US EPA 100% (75 mm) 90% to 100% 65% to 100% 0 to 75%
IN DNR 100% 99% 90% 0 to 90%
CONEG 100% 100% 100% 70% (13 mm), 50% (2 mm)
* 1:1 blend of compost and untreated wood chips (termed erosion control compost).
is unclear if these specifications have ever
been scientifically evaluated. Mukhtar et al.
(2004) reported that TX DOT specifications
were followed, however, particle size distri-
bution was not reported.
Larger particles are the primary material
that prevents soil loss—like organic litter and
debris on a forest floor, while the small parti-
cles (compost fines) are the primary material
that absorbs rainfall thereby preventing runoff
—like humus on a forest floor. Large particles
prevent splash erosion and soil dislodgement
by reducing the energy of raindrop impact;
additionally, they reduce sediment trans-
port in overland runoff by reducing runoff
rates due to their size and weight. Small
particles can absorb a significant volume of
rainwater thereby increasing the infiltration
capacity and allowing for more evaporation.
Additionally small particles probably provide
nutrients and enhance soil structure for plant
root growth. Good plant root establishment
will allow for healthy plant establishment
and will help maintain necessary cover
aiding erosion control/slope stabilization.
It is also likely that any benefit of increased
soil quality (in the future) will result mainly
from the small particles in the compost
erosion control blanket (and biota in the soil
and compost).
The cover management factor (C factor)
is one of six factors used in the Universal
Soil Loss Equation (USLE). The C factor
indicates how an erosion control practice,
erosion control product, or conservation
plan will affect average annual soil loss.
Although determining C factors can be
complicated, the erosion control industry has
greatly simplified the process to quickly and
inexpensively evaluate their erosion control
products so equation users (designers, engi-
neers, architects) can readily and easily insert
specific product C factors into the USLE
(Demars and Long 1998; ECTC 2004). To
do this, product manufacturers (and/or their
third party testing labs) determine the sin-
gle-event soil loss ratio of the specific erosion
control product relative to a bare soil under
406 journal of soil and water conservation
Table 2
Reported C factors for various rolled and blown-on erosion control blankets.
Product/practice (reference) C factor Inuencing factors
Hydraulic mulch + synthetic or ber netting (ECTC 2004) <0.10 5:1 slope; ECTC test method
Netless rolled erosion control blanket (bound by polymers or <0.10 4:1 slope; ECTC test method
chemical adhesion) (ECTC 2004)
Single net erosion control blanket (natural materials <0.15 3:1 slope; ECTC test method
woven/mechanically bound) (ECTC 2004)
Double net erosion control blanket (natural materials <0.20 2:1 slope; ECTC test method
woven/mechanical bound between 2 layers) (ECTC 2004)
Erosion control blanket/open weave textile (slow degrading, <0.25 1.5:1 slope; ECTC test method
continuous weave double net ECB) (ECTC 2004)
Turf reinforcement mat (permanent/nondegradable, None (usually 0.5:1 slope; ECTC test method
3-dimensional thickness, used in concentrated ows) tested for
(ECTC 2004) shear stress)
Straw blanket (Demars and Long 1998) 0.08 2:1 slope; natural rainfall (max. 1.6/24 hr);
10 ft x 35 ft test plot; on silty sand
Straw blanket w/pam (Faucette n.d.) 0.19 10:1 slope; 4 in/hr 1hr rainfall; 3 ft x 16 ft test plot;
clay subsoil; 2 in blanket
Mulch blanket (Demars & Long 1998) 0.075 2:1 slope; natural rainfall (max. 1.6/24 hr);
10 ft x 35 ft test plot; on silty sand; 3 in blanket
Mulch nes (Faucette et al. 2004) 0.16 10:1 slope; 3.2 in/hr 1 hr rainfall; 3 ft x 3 ft test plot;
clay subsoil; 1.5 in blanket
Mulch overs (Faucette et al. 2004) 0.11 10:1 slope; 3.2 in/hr 1 hr rainfall; 3 ft x 3 ft test plot;
clay subsoil; 1.5 in blanket
Wood chips @ 7 tn ac–1 (GA SWCC 2000) 0.08
Wood chips @ 12 tn ac–1 (GA SWCC 2000) 0.05
Wood chips @ 25 tn ac–1 (GA SWCC 2000) 0.02
Compost blanket (Demars 1998) 0.05 2:1 slope; natural rainfall (max. 1.6/24 hr);
10 ft x 35 ft test plot; on silty sand; 3 in blanket
Compost blanket (Demars et al. 2000) 0.02 2:1 slope; natural rainfall, 10 ft x 35 ft test plot;
on silty sand; 3 in blanket
Compost blanket (Mukhtar et al. 2004) 0.008 3:1 slope; 3.6 in/hr 30 min runoff; 3 ft by 6 ft test plot;
on clay soil; 2 in blanket
Compost blanket (Faucette et al. 2005) 0.01 10:1 slope; 3.2 in/hr 1 hr rainfall; 3 ft x 16 ft test plot;
clay subsoil; 1.5 in blanket
Forest duff layer (GA SWCC. 1993) 0.001 to 0.0001
Note: ECTC = Erosion Control Technology Council.
the same test conditions. Consequently, the
lower the soil loss from an erosion control
practice/product relative to bare soil, the
lower the soil loss ratio, and therefore the
lower the C factor. The lower the C factor
the better the erosion control practice/prod-
uct is at preventing soil loss. See table 2 for a
list of reported C factors for compost ECBs,
rolled ECBs, wood mulch, straw mulch, and
natural forest duff.
Research Objective. The primary objective
of this study was to determine how blending
wood mulch with compost may affect the
compost’s performance as an erosion control
best management practice (BMP) relative to
a straw blanket with polyacrylamide (PAM
[industry standard BMP]). Because vegeta-
tion establishment is the primary goal for
permanent slope stabilization, wood mulch
was blended with compost in varying ratios
to determine the maximum possible inclu-
sion rates without detrimental effects to
plant establishment. The secondary objective
of this study was to determine if particle size
distribution of the organic erosion control
blanket affects runoff and erosion. To deter-
mine the effectiveness of the ECBs, analysis
of storm water quantity and quality included
total runoff volume, peak runoff rate, per-
cent of runoff from rainfall, elapsed time
until runoff commencement, total sediment
load, suspended solids load, average turbidity,
nitrogen load, and phosphorus load. Results
from vegetation analysis will be reported in a
follow up study.
Materials and Methods
Site Description. Research test plots were
constructed at Spring Valley Farm in Athens/
Clarke County, Georgia, at 33°57'N lati-
tude and 83°19'W longitude. The soil was
mapped as an eroded Pacolet Sandy Clay
Loam (USDA 1968) and has a high soil
erodibility factor (K value) of approximately
0.36 (Wischmeier and Smith 1978). The area
receives an average annual rainfall of 1,215
mm (48 in), with January through March as
the wettest period. The average annual high
temperature for the area is 22°C (72°F), the
average low is 11°C (52°F), with a mean
annual temperature of 17°C (63°F) (Weather
Channel 2005). The field experiment was
conducted in the summer of 2005.
The testing area was cleared of vegetation
and graded to a 10% slope with a grading
blade mounted skid steer, exposing a semi-
compacted (from the skid steer) subsoil (Bt
407
nov | dec 2007 volume 62, number 6
horizon) to simulate construction site con-
ditions. Test plot borders were installed to
prevent cross contamination of plots. Fifteen
cm (6 in) wide stainless steel borders were
trenched 7.5 cm (3 in) into the soil. The
plots were sized to fit the effective rainfall
distribution from the rainfall simulator, 1.0
m (3.3 ft) wide by 4.8 m (16 ft) long, for a
total plot area of 4.8 m2 (53 ft2). A remov-
able flume was installed at the base of each
plot prior to each simulated rainfall event. A
removable stainless steel border was carefully
inserted at the base of each plot, once the
flume was removed after each storm event,
to maintain the structure and integrity of the
soil in the plot. The soil was carefully com-
pacted around the removable flume and the
removable border after each one was installed
for use. Nine cumulative non-recording rain
gauges were installed in each plot to measure
rainfall quantity. Three each were spaced
evenly across the width of the plot at 1.2 m
(4 ft), 2.4 m (8 ft) and 3.6 m (12 ft) from the
top of the plot.
Treatments. Treatments included (1) 100%
chipped wood mulch blanket; (2) 100% yard
waste compost blanket; (3) 2:1 compost:wood
mulch blended blanket (2:1 blend); (4) 1:2
compost:wood mulch blended blanket (1:2
blend); (5) 1:2 compost:wood mulch blended
blanket with clover seed added; (6) straw
blanket with PAM and 10-10-10 fertilizer;
(7) 100% compost blanket with a proprietary
PAM blend (PAM1); (8) 100% compost blan-
ket with another proprietary PAM (PAM2);
(9) 100% compost blanket with a proprietary
biopolymer derived from corn starch (Bio-
Floc); and (10) a bare soil (control). Compost
and wood mulch were accepted as-is from
suppliers. Compost was blended with the
wood mulch to aid in vegetation establish-
ment—the primary goal for permanent
erosion control/slope stabilization. The straw
blanket with fertilizer and PAM represents an
industry standard BMP commonly used in
this type of application under the conditions
described in the previous section, as specified
by G DOT. The primary difference between
PAM1 and PAM2 is that PAM2 is attached
to a pigmented paper fiber carrier to allow
for easy material application. PAM and Bio-
Floc products were manually surface applied
to the compost blankets to determine if there
may be a potential water quality benefit from
reduced soil erosion by using these materials
in combination with organic blankets. All ten
treatments were randomly assigned to field
test plots. Each treatment was replicated in
triplicate.
Compost, wood mulch, and compost/
wood mulch blankets were manually applied
at a 3.75 cm (1.5 in) depth over the entire
area of the plot. Application depth of the
blankets followed AASHTO specifications
for erosion and sediment control (AASHTO
2003). Straw blankets were applied at a 3.75
cm (1.5 in) depth over the entire area of the
plot, according to G DOT specifications. A
10-10-10 commercial fertilizer was applied
according to G DOT specifications at 1,344
kg ha-1 (1,200 lbs ac-1) (G DOT 2004), the
PAM with straw blanket and PAM2 with
compost blanket was applied at 370 kg ha-1
(330 lbs ac-1), PAM1 with compost blanket
was applied at 34 kg ha-1 (30 lbs ac-1), and the
Bio-Floc was applied at 112 kg ha-1 (100 lbs
ac-1). All polymer product application rates
followed their manufacturer’s specifications.
Compost blanket application specifications
for vegetation establishment do not require
additional fertilizer (the specifications assume
there is adequate nutrients within the com-
post) therefore the straw blanket with PAM
treatment was the only treatment to receive
additional fertilizer.
Each treatment, including the control,
was seeded with hulled Common Bermuda
(Cynodon dactylon) grass seed applied at 22 kg
ha-1 (20 lb ac-1), specified by the G DOT as
an erosion and sediment control vegetative
measure for slopes 3:1 or less for the Athens,
Georgia region. A 1:2 (compost:wood
mulch) blend received a mixture of red clo-
ver (Trifolium pratense) 7 kg ha-1 (6 lb ac-1)
and common bermuda grass 16 kg ha-1 (14 lb
ac-1) in order to alleviate potential N immo-
bilization due to the high C addition created
by the wood mulch. Results from vegeta-
tion analysis will be reported in part two of
this study. The compost, mulch, and com-
post/mulch treatments were physically and
chemically characterized prior to application
in the test plots (table 3). It should be noted
that the 100% compost treatments did not
meet particle size distribution specifications
(this is how it was received from supplier),
while all other treatments using compost or
mulch met particle size specifications.
Rainfall Simulator. A Norton Rainfall
Simulator with four variable speed V-jet
oscillating nozzles originally obtained from
the USDA ARS National Soil Erosion
Research Lab was used to simulate rain
events as described and previously used for
erosion control experiments by Faucette et
al. (2005). During rain events water pressure
to the nozzles was maintained at 0.42 kg cm-2
(6 psi), according to manufacturer’s specifica-
tions, producing an intensity of 10 cm (4.0
in) hr-1 for 1 hr duration. This is equivalent
to the one-hour storm event for a 100-
year return period for the Athens, Georgia,
region, based on historical rainfall records
(US Department of Commerce 1961). It was
our intention to evaluate these treatments
under a “worst-case” scenario because most
runoff and erosion occurs during these large
rainfall events. Municipal tap water was used
in this study containing NO3-N of 0.673 mg
L-1 and PO4-P of 0.093 mg L-1.
Two simulated rainstorms were conducted:
one at the beginning of the experiment and
one three months later. These time intervals
were chosen based on the predicted estab-
lishment of the vegetation. The first runoff
event was intended to provide information
on the performance of the treatments prior to
vegetation establishment. The second runoff
event was intended to provide information
on how the performance of the treatments
changed when vegetation was newly estab-
Table 3
Chemical and physical characteristics of treatments as applied to the research site.
Particle size (percent passing)
NH4-N NO3-N OM
Treatment C N C:N (mg kg–1) (mg kg–1) (percent ash) 1.25 cm 0.625 cm 0.313 cm 0.156 cm
100% wood mulch 49.08% 0.23% 213 5.2 0.2 3.05% 64% 30% 3% 1%
1:2 blend 43.29% 0.61% 71 9.9 0 25.46% 85% 67% 41% 32%
2:1 blend 33.33% 1.14% 29 9.9 0.6 36.84% 89% 76% 52% 38%
100% compost* 20.84% 1.16% 18 12.5 1.4 50.44% 99% 95% 79% 60%
*Did not meet AASHTO specication for erosion control blanket particle size distribution (0 to 75% passing 0.625 cm).
408 journal of soil and water conservation
lished. All of the plots were subjected to
natural rainfall between the simulated rainfall
events. A total of 24 cm (9.6 in) of precipita-
tion accumulated between the two simulated
runoff events, which will be described in the
following section (Weather Channel 2005).
Compost and Mulch Sampling and
Analysis. Physical and chemical analy-
ses of the treatments were performed at
Auburn University. Total C and total N were
analyzed on a Perkin Elmer 2400 (Perkin-
Elmer 2400 series II CHNS/O analyzer;
Perkin-Elmer Corp., Norwalk, Connecticut);
organic matter was determined by weight
difference after loss on ignition at 500°C
(932°F). Nitrate-N and ammonium-N sam-
ples were first extracted using a 100 mL (3.4
fl oz) solution of 2 M KCl, placed on a shaker
for 1 hr, and then filtered with Whatman
42 filter paper before colorimetric analysis
using a microplate reader (Bio-Rad Model
450 microplate reader, Bio-Rad Laboratories,
Hercules, CA.) (Sims et al. 1995). Particle
size analysis for compost, wood mulch,
and compost/mulch treatments used 300 g
(0.67 lb) dried subsamples and followed
the Test Methods for the Examination of
Composting and Compost (USCC 1997)
for distribution of particle sizes for compost.
Size of sieves included 25.4 mm (1 in), 19.05
mm (3/4 in), 15.88 mm (5/8 in), 12.7 mm
(1/2 in), 9.52 mm (3/8 in), 6.35 mm (1/4
in), 4 mm (#5), 3.18 mm (1/8 in), 2.0 mm
(#10), 1.0 mm (#18), 500 µm (#35), 53 µm
(#270), 25 µm (#500).
Runoff Sampling and Analysis. Sampling
and analyses for storm water included rainfall
amount, time until start of runoff, time until
steady state of runoff flow rate, total runoff
volume, percent of rainfall as runoff, peak
runoff rate, total solids concentrations and
loads, suspended solids concentrations and
loads, turbidity, total nitrogen concentrations
and loads, and total phosphorus concentra-
tions and loads.
Runoff sampling procedures and calcula-
tion methods followed procedures used for
the Water Erosion Prediction Project devel-
oped by the USDA National Soil Erosion
Research Lab which have been used in simi-
lar studies (Glanville et al. 2001; Faucette et al.
2004). Runoff samples were collected from a
flume placed at the base of each plot. The
first sample was taken once water began to
“trickle” from the flume aperture, the point
determined to be the start of runoff. After
the first sample was collected, samples were
taken every five minutes until the 60-minute
storm was finished. To obtain samples of run-
off quantity and total solids, we used one 500
mL (16.9 fl oz) Nalgene bottle per 5-minute
interval sample, and “seconds-to-fill” bottle
times were recorded to obtain runoff flow
rates. Laboratory analysis of the nutrients
in runoff water was conducted at Auburn
University and the University of Georgia.
Phosphorus was analyzed on all samples.
For phosphorus (P) water samples were first
filtered with a 0.45 micron filter and then
processed on a Dionex ion chromatograph
(Sunnyvale, California). Total Kjeldahl nitro-
gen (TKN) was analyzed on the first and
final samples.
A subsample from each 500 mL (16.9 fl
oz) runoff/solids sample was weighed and
oven dried at 105°C (221°F) until constant
weight was achieved to determine the total
solids content. The total solids were mea-
sured using methods 2540 B total solids
dried at 103°C to 105°C (217°F to 221°F)
(USEPA 1983). Total suspended solids were
determined following methodology outlined
by the USEPA (1999). Turbidity (NTUs)
was measured using a LaMotte model 2020
turbidity meter. The peak runoff rate (once
flow reached steady state conditions) was
determined once runoff rates were equal for
three consecutive time adjacent samples. The
runoff rate (known volume per measured
time) sampled at 5-minute intervals dur-
ing the simulation was plotted and the total
runoff volume was calculated by summing
the area under the runoff curve.
Total solids and total suspended sol-
ids loads were calculated by summing
the average concentration of two time-
adjacent concentration samples multiplied by
the average of the same two time-adjacent
samples for runoff volume. C factors were
determined for each treatment based on total
solids loads from the first storm event. C fac-
tors were not determined for the final storm
event as it was assumed results would be more
reflective of the vegetation and not the origi-
nal erosion control blanket. C factors were
determined based on the single-event soil loss
ratio of each treatment relative to the control
(Demars and Long 1998; ECTC 2004).
Statistical Analysis. SAS version 8.2 (SAS
Institute 2001) was used for statistical analy-
sis. Separation of means was determined
by PROC ANOVA using Duncan’s mul-
tiple range test to determine any significant
differences between treatments (p 0.05).
Prior to means separation using Duncan’s
multiple range test, Type 1 error was con-
trolled for at the p 0.05 level and any
resultant pr > F values > 0.05 were not
deemed to be significant.
Results and Discussion
Runoff Volume. Most ECBs are not designed
to hold a tremendous amount of rainwater.
However, an ECB with a greater water hold-
ing capacity is likely to produce less run-
off and possibly prevent runoff under low
to medium rainfall intensity and/or short
duration storms. A quantifiable reduction in
storm water runoff by an ECB can reduce
the design size of storm water management
or sediment retention ponds and therefore
offer a cost savings to developers and build-
ers; furthermore it can increase the avail-
able footprint for development, recreation
or conservation opportunities. Additionally,
an ECB that reduces sheet runoff will likely
have less soil erosion due to a reduction in
soil transport and erosivity wrought by storm
runoff.
During the first runoff event, relative to
the bare soil, the 100% compost blanket
reduced storm water runoff by 52%, the
2:1 blanket by 54%, the 1:2 blanket by 42%
(mean of treatments with and without clover
prior to germination), the 100% wood mulch
blanket by 23%, and the straw blanket with
PAM by 12% (table 4). The PAM and Bio-
Floc additions to the compost blankets had
no effect on runoff volume. The compost
blends retained between 84% and 90% of the
total rainfall applied to the area, while the
wood mulch and straw blanket treatments
only retained 74%. The 100% compost and
compost blended blankets were significantly
lower in runoff volume (and retained rain-
fall volume) relative to the 100% wood
mulch, straw blanket with PAM, and bare
soil treatments.
By the second runoff event, once veg-
etation was established, the 100% compost
blanket reduced storm water runoff by
69%, the 2:1 blanket by 81%, the 1:2 blan-
ket by 67%, the 1:2 blanket with clover by
69%, the 100% wood mulch blanket
by 45%, and the straw blanket with PAM by
45%. Additionally, the compost and compost
blended treatments retained approximately
70% of the total rainfall volume applied while
the 100% wood mulch and straw blankets
retained approximately 50%. Statistically, the
100% compost and compost blended treat-
409
nov | dec 2007 volume 62, number 6
Table 4
Runoff volume and percent runoff from rainfall for two storm events and seven treatments.
Treatment Runoff 1 (L) Runoff 2 (L) Total runoff (L) Percent runoff 1 Percent runoff 2 Average percent
Bare soil 251a 227a 478 52%a 54%a 53%
Straw w/ PAM 222ab 125abc 347 26%ab 49%bcd 38%
100% wood mulch 193abc 124abc 317 26%abc 46%bcd 36%
1:2 blend 126bcd 71bc 197 16%bcde 31%bcd 24%
1:2 blend w/ clover 164cd 75bc 239 16%de 31%bcd 24%
2:1 blend 115cd 44c 159 10%cde 28%d 19%
100% compost 120cd 70bc 190 14%de 28%cd 21%
Note: Treatments with same letter are not signicantly different at α = 0.05 using Duncan’s multiple range test.
ments were significantly lower than the bare
soil in total runoff, while the straw and 100%
wood mulch blankets were not; additionally,
the 100% compost and 2:1 compost blankets
retained significantly more rainfall than the
straw and 100% wood mulch blankets, while
all treatments retained significantly more
rainfall than the control.
Over both runoff events, the 100% com-
post blanket reduced total storm water runoff
by 60%, the 2:1 blanket by 67%, the 1:2
blanket by 54%, the 1:2 blanket with clover
by 55%, the 100% wood mulch blanket by
34%, and the straw blanket with PAM by
27%. The erosion control treatments with
a greater percentage of compost retained
an average of 80% of the cumulative total
rainfall volume, the treatments with a greater
percentage of wood mulch retained an aver-
age of 75%, and the 100% wood mulch and
straw blankets retained an average of approx-
imately 65% and 60%, respectively. These
results were likely due to the higher water
holding capacity of compost, presumably
because of its higher humus content, relative
to the other treatments.
Time until Start of Runoff and Peak Runoff
Rate. Measuring the elapsed time until run-
off commencement is a way to evaluate how
an ECB BMP may perform under specific
storm conditions. The longer an ECB can
prevent the occurrence of runoff, the longer
it is preventing sediment transport, particu-
larly under low to medium rainfall intensity
storms. During the first runoff event, relative
to the bare soil, the 100% compost blanket
increased the time to runoff commencement
six fold, the 2:1 blanket 9 fold, the 1:2 blan-
ket 5 fold, the 100% wood mulch blanket 4
fold, and the straw blanket with PAM2 fold
(table 5). Reduction in runoff time was likely
due to the higher water holding capacity of
compost, presumably because of its higher
humus content, relative to the other treat-
ments. Statistically, the 100% compost and
compost blended blankets took significantly
longer to commence runoff relative to the
straw blanket and bare soil. While the 100%
wood mulch blanket was significantly differ-
ent from the control it was statistically similar
to the straw blanket. The PAM and Bio-Floc
additions to the compost blanket had no
affect on runoff commencement.
During the second runoff event, the
compost blanket and 2:1 blend delayed the
onset of storm runoff by nearly 40% relative
to the straw blanket/PAM and 100% wood
mulch treatments. Statistically, only these
two ECBs were significantly different from
the control.
An important component of an effective
ECB is its ability to reduce surface runoff
rates. Lower runoff rates are generally less
likely to dislodge and transport soil particles,
and are therefore less erosive. In some cases
slower runoff is more likely to infiltrate.
During the first runoff event, relative to the
bare soil, the compost blanket reduced run-
off rates by 34%, the 2:1 blanket by 32%, the
1:2 blanket by 33%, the wood mulch blanket
by 20%, and the straw blanket with PAM
by 7%. The PAM and Bio-Floc additions to
the compost blanket had no affect on runoff
rates. Statistically, the compost blanket sig-
nificantly reduced runoff rates relative to the
straw blanket and control, while no other
differences were statistically significant.
By the second runoff event, the compost
blanket reduced storm water runoff rates by
51%, the 2:1 blanket by 53%, the 1:2 blan-
ket by 52%, the 1:2 blanket with clover
by 55%, the wood mulch blanket by 32%,
and the straw blanket with PAM by 33%.
Statistically, the compost and compost/wood
mulch ECBs significantly lowered runoff
rates relative to the control, while the straw
and wood mulch blankets did not.
Over both runoff events, the compost
blanket and 2:1 blanket reduced average
peak runoff rate by 43%, the 1:2 blanket by
Table 5
Elapsed time to start of runoff (min) and peak runoff rate for two storm events and seven treatments.
Start 1 Start 2 Average start Runoff rate 1 Runoff rate 2 Average rate
Treatment (minutes) (minutes) (minutes) (mL s–1) (mL s–1) (mL s–1)
Bare soil 2e 3b 3 88a 85a 87
Straw w/ PAM 4de 14ab 9 82a 56abcd 69
100% wood mulch 7dc 15ab 11 70ab 58abcd 64
1:2 blend 10c 16a 13 53abc 38bcd 46
1:2 blend w/ clover 11c 26ab 19 66bc 41cd 54
2:1 blend 17b 24ab 21 60abc 40bcd 50
100% compost 11c 22a 17 58bc 42bcd 50
Note: Treatments with same letter are not signicantly different at α = 0.05 using Duncan’s multiple range test.
410 journal of soil and water conservation
38%, the 1:2 blanket with clover by 47%, the
wood mulch blanket by 26%, and the straw
blanket with PAM by 21%. The reduction
in peak runoff rate by the ECB treatments
with a greater ratio of compost is likely due
to the heterogeneous mixture of particle
sizes which help to disrupt and slow over-
land sheet flow.
Total Solids and C Factors. After the
first runoff event, the smaller particles in
the compost blanket showed evidence of
movement downslope, creating horizontal
formations across the slope (as opposed to
rill formations vertically downslope charac-
teristic to soils), while the larger particle sizes
did not move and appeared to prevent the
further movement of the smaller particles.
This did not occur in the compost/wood
mulch blends or 100% wood mulch blan-
kets, providing evidence that the compost
blankets likely would be more effective if the
particle size distribution had a greater per-
centage of large particles, particularly when
exposed to intense storms—characteristic of
this study. It should be noted that the particle
size distribution of the 100% compost ECBs
did not meet specifications for compost
ECBs according to AASHTO (2003), as 95%
of the particles passed a 0.625 cm (1/4 in)
sieve, whereas, according to the AASHTO
specifications this should be 0 to 75%. It is
the opinion of the researchers that failure
to meet this specification likely resulted in
greater solids loss relative to compost ECBs
that meet the specification, and that a higher
percentage of larger particles would greatly
reduce the loss of solids under most storm
conditions. It should also be noted that all
other treatments utilizing compost or mulch
met particle size distribution specifications.
Table 6
Total solid loads, suspended solid loads, and turbidity for two storm events and ten treatments.
Average
TS 1 TS 2 TS total TSS 1 TSS 2 TSS total Turbidity 1 Turbidity 2 turbidity
Treatment (kg ha–1) (kg ha–1) (kg ha–1) (kg ha–1) (kg ha–1) (kg ha–1) (NTU) (NTU) (NTU)
Bare soil 5,575a 1,271a 6,846 3,215a 2,083a 5,279 12,935a 2,437a 7,686
Straw w/ PAM 1,054b 56b 1,110 613b 42b 654 1,828b 51b 940
100% wood mulch 73b 23b 96 31b 21b 52 53b 19b 36
1:2 blend 108b 21b 129 13b 48b 60 65b 54b 60
1:2 blend w/ clover 148b 19b 167 21b 21b 42 65b 27b 46
2:1 blend 185b 23b 208 29b 35b 65 127b 46b 87
100% compost 363b 46b 408 194b 90b 283 470b 105b 288
Compost w/ PAM1 ND ND ND 298b 94b 392 228b 175b 202
Compost w/ PAM2 ND ND ND 373b 77b 450 512b 104b 308
Compost w/ Bio-Floc ND ND ND 106b 108b 215 121b 157b 139
Notes: TS = total solid load. TSS = total suspended solid load.Treatments with same letter are not signicantly different at α = 0.05 using Duncan’s
multiple range test. ND = no data.
Total solids load reduction, relative to
bare soil, during the first runoff for the com-
post blanket was 93%, the 2:1 blanket was
97%, the 1:2 mix was 98%, the wood mulch
blanket was 99%, and the straw blanket with
PAM was 81% (table 6). All treatments had
96% or greater reduction of total solids dur-
ing the final runoff event. All treatments
were significantly different from the con-
trol but not from each other for both runoff
events.
Cover management factors, commonly
used by the erosion control industry to
evaluate the erosion control performance of
blanket or mat technology, were determined.
Table 7 lists C factors that were determined
for the ECBs in the study. Faucette et al.
(2005) reported a C factor for compost blan-
kets over two storm events on a 10% slope
to be 0.008, and hydroseed with a silt fence
(used for additional sediment control—not
erosion control) was 0.044. Demars and
Long (1998) reported a C factor of 0.05 for
compost blankets, 0.075 for mulch blankets,
and 0.08 for straw blankets. Based on the site
and rainfall characteristics used in this study,
compost blankets had a C factor of 0.065,
wood mulch was 0.013, blending the mate-
rials together generated a C factor between
0.023 and 0.033, and straw blankets gener-
ated a C factor of 0.189. C factors for this
study were likely higher relative to those
reported in the literature due to the high
rainfall intensity that was simulated.
Suspended Solids and Turbidity. The per-
cent reduction in loading of suspended solids
during the first runoff event for the straw
blanket with PAM was 81%, compost blanket
was 94%, compost blanket with PAM1 was
88%, compost blanket with PAM2 was 91%,
compost blanket with Bio-Floc was 97%,
and the 2:1, 1:2, and wood mulch blankets
were all 99% effective (table 6). All treatments
had 96% or greater reduction of suspended
solids during the final runoff event. All treat-
ments were significantly different from the
control but not from each other for both
runoff events.However, all treatments con-
taining wood mulch had significantly lower
suspended solids concentrations relative to
the straw/PAM blanket for the first runoff
event.
The percent reduction in turbidity during
the first runoff event for the straw blanket
with PAM was 86%, compost blanket was
96%, compost blanket with PAM1 was 96%,
compost blanket with PAM2 was 98%, and
the compost blanket with Bio-Floc, the 2:1,
1:2, and wood mulch blankets were all 99%
effective. All treatments had 98% or greater
reduction of turbidity during the final run-
off event, with the exception of the compost
blanket which had 96%. All treatments were
significantly lower in turbidity, relative to
the control, for both runoff events.
The superior performance of wood
mulch blankets to prevent erosion is prob-
Table 7
Treatment C factors.
Treatments C factors
Bare soil 1.0
Straw w/ PAM 0.189
100% wood mulch 0.013
1:2 blend 0.023
2:1 blend 0.033
100% compost 0.065
411
nov | dec 2007 volume 62, number 6
ably attributable to their ability to reduce
raindrop impact energy and soil particle dis-
lodgement, due to complete cover of the
soil surface, and to a relatively high ratio of
large particle sizes in the blanket—which
are also less likely to be lost to runoff trans-
port. The researchers feel that if the compost
ECB had met the particle size specification
requirement (needing a greater percentage
of large particles), the sediment loss results
would be similar to the wood mulch. The
greater soil loss from the straw blankets may
be attributable to a lower ability to reduce
raindrop impact energy, runoff volume, and
flow rate.
Under these rainfall, soil, and site condi-
tions, total soil loss can be four times as high,
suspended solids can be five times as high,
and turbidity can be eight times as high if
compost ECB particle size distribution does
not meet specifications relative to a compost
ECB that does meet particle size distribu-
tion specifications (table 8). Additionally,
depending on which specification is fol-
Table 8
Soil loss and particle size distribution for compost and mulch erosion control blanket treatments.
Suspended Particle size % passing
Soil loss solids Turbidity
Treatment (kg ha–1) (kg ha–1) (NTU) 25 mm 12 mm 6 mm
100% wood mulch 95.8 52.1 36 99 64 30
1:2 blend* 129.2 60.4 60 99 85 67
2:1 blend* 208.3 64.6 87 99 89 76
100% compost† 408.3 283.3 288 99 99 95
* Did not meet TX DOT specication for erosion control compost particle size distribution.
† Did not meet TX DOT, USEPA, IN DNR, or CONEG specication for erosion control blanket
particle size distribution.
lowed (TX DOT, AASHTO, USEPA, IN
DNR, CONEG), total soil loss and turbid-
ity can be twice as high from one compost
specification relative to another.
Nitrogen and Phosphorus Loss. Nutrient
loss from fertilizers used to establish vegeta-
tion for erosion control at construction sites
has not been well documented (although
it has been for agriculture). While the bare
soil contributed to TKN loading during
the first runoff event (1.71 kg ha-1 [1.53
lb ac-1]), the straw blanket with PAM con-
tributed 8,000% more TKN than the bare
soil, the compost blanket contributed
340% more, the 2:1 blanket contributed
277% more, the 1:2 blanket contributed
209% more, and the wood mulch released
18% more (table 9). Statistically, the straw/
PAM blanket was significantly greater than
all other treatments, with no statistical dif-
ference between the remaining blankets and
the control. Increased nitrogen loss from all
treatments, relative to the control, was due to
leaching and transport from intensive rainfall
and runoff conditions. Because mass loading
was evaluated, as opposed to concentrations,
values were greatly affected by runoff vol-
ume, whereas, treatments that reduce runoff
Table 9
Total Kjeldahl nitrogen loads and soluble phosphorus loads for two storm events and seven treatments.
TKN load 1 TKN load 2 TKN total P load 1 P load 2 P load total
Treatment (kg ha–1) (kg ha–1) (kg ha–1) (g ha–1) (kg ha–1) (kg ha–1)
Bare soil 1.7b 0.7a 2.4 0b 43.8d 43.8
Straw w/ PAM 136.4a 0.8a 137.2 154,616.7a 154.2d 154,770.9
100% wood mulch 2.0b 1.3a 3.3 0b 18.8d 18.8
1:2 blend 2.7b 7.4a 10.1 1,716.7b 289.6cd 2,006.3
1:2 blend w/ clover 4.5b 7.4a 11.9 3,035.4b 304.2cd 3,339.6
2:1 blend 4.7b 1.7a 6.4 4,706.3b 454.2cd 5,160.4
100% compost 5.8b 4.7a 10.5 4,058.3b 552.1cd 4,610.4
Note: Treatments with same letter are not signicantly different at α = 0.05 using Duncan’s multiple range test.
volume will likely emit lower N loads rela-
tive to those that may not reduce runoff
volume to the same extent. Additionally, N
from fertilizer (like that specified for veg-
etation establishment for straw blankets) is
generally in mineral/inorganic form and is
more likely to be transported under runoff
conditions, relative to organic N typically
supplied by compost ECBs.
By the second runoff event, TKN loss
from all ECBs was much lower relative to
the first simulated storm, suggesting that N
loss may only be a serious concern during
the first runoff event after treatment applica-
tion. Although TKN loads from the compost
blankets appeared to be greater than the
remaining treatments, TKN concentrations
of the storm runoff were less than 5 mg L-1
(5 ppm). There were no statistically signifi-
cant differences between treatments during
the second runoff event.
In addition to nitrogen, phosphorus load-
ing and its potential eutrophication effects
to receiving waters has become an increas-
ing concern. Soluble phosphorus (P) is of
greatest concern as it is often immediately
available to aquatic plants once it enters sur-
face water, leading to algal blooms. While
the bare soil and the wood mulch blanket
treatments did not contribute any soluble P
from runoff, relative to the compost ECB,
the soluble P load from the straw blanket
with PAM was 3,800% greater, the 2:1 blan-
ket was 16% greater, and the 1:2 blanket
was 41% less. The reduction in P load from
the 1:2 blanket is likely because of the high
ratio of wood mulch relative to compost, as
the wood mulch releases very little soluble
P. Statistically, the straw/PAM blanket was
significantly greater than all other treatments,
with no statistical difference between the
remaining blankets and the control.
By the second runoff event, soluble P
loads for all treatments were greatly reduced
412 journal of soil and water conservation
relative to the first simulated storm. Most
soluble P probably migrated off-site from the
initial runoff event, while some may have
been adsorbed to soil colloids or taken up
by the vegetation. There were no statistically
significant differences between treatments
during the second runoff event.
The results of the experiment indicate
nutrient loading to receiving waters from
conventional seeding (and fertilizer) appli-
cations for conventional ECBs may be a
significant issue. Wood mulch ECBs offer
an alternative that may significantly reduce
nutrient loading. However, due to its inabil-
ity to support vegetation wood mulch ECBs
can only be viewed as a temporary erosion
control/slope stabilization practice. Adding
compost to wood mulch, or using only
compost ECBs, is a viable alternative due
to its ability to supply organic nutrients to
plants. The lower amount of N and P load-
ing is likely because compost significantly
reduces runoff volume, which reduces total
nutrient loading, and because nutrients are
typically in organic form which makes them
less mobile than soluble inorganic nutrients
(characteristic of fertilizers) under storm run-
off conditions.
Summary and Conclusions
During the first simulated storm event the
compost blanket reduced storm water run-
off by 52%, the 2:1 blanket by 54%, the 1:2
blanket by 42%, the wood mulch blanket by
23%, and the straw blanket with PAM by
12%. The compost blends retained between
84% and 90% of the total rainfall applied to
the area, while the wood mulch and straw
blanket treatments retained 74% of the total
rainfall volume applied. Over both runoff
events, the compost blanket reduced cumu-
lative storm water runoff by 60%, the 2:1
blanket by 67%, the 1:2 blanket by 54%, the
1:2 blanket with clover by 55%, the wood
mulch blanket by 34%, and the straw blanket
with PAM by 27%. In addition, the erosion
control treatments with a greater percent-
age of compost retained an average of 80%
of total rainfall, while the treatments with a
greater percentage of wood mulch retained
an average of 75%, and the wood mulch and
straw blankets retained an average of approx-
imately 65 and 60%, respectively.
During the first runoff event the compost
blanket increased the time to runoff com-
mencement sixfold, the 2:1 blanket ninefold,
the 1:2 blanket fivefold, the wood mulch
blanket fourfold, and the straw blanket with
PAM twofold. After vegetation was estab-
lished, ECBs that were all or mostly compost
delayed the onset of storm runoff by nearly
40% relative to the straw blanket/PAM and
wood mulch treatments.
During the first runoff event, the compost
blanket reduced peak runoff rates by 34%,
the 2:1 blanket by 32%, the 1:2 blanket by
33%, the wood mulch blanket by 20%, and
the straw blanket with PAM by only 7%.
Averaged over both runoff events, the com-
post blanket and 2:1 blanket reduced average
peak runoff rate by 43%, the 1:2 blanket by
38%, the 1:2 blanket with clover by 47%, the
wood mulch blanket by 26%, and the straw
blanket with PAM by 21%.
Total soil loss reduced (relative to bare
soil) during the first runoff for the straw
blanket with PAM was 81%, the compost
blanket was 93%, the 2:1 blanket was 97%,
the 1:2 blanket was 98%, and the wood
mulch blanket was 99%. All treatments had
96% or greater reduction of total solids dur-
ing the final storm event. The C factor for
the straw blanket with PAM was 0.189, the
compost blanket was 0.065, the 2:1 blanket
was 0.033, the 1:2 blanket was 0.023, and
the 100% pine mulch blanket was 0.013.
The percent reduction in suspended sol-
ids loading during the first runoff event for
the straw blanket with PAM was 81%, the
compost blanket was 94%, compost blanket
with PAM1 was 88%, compost blanket with
PAM2 was 91%, compost blanket with Bio-
Floc was 97%, and the 2:1, 1:2, and wood
mulch blankets were all 99% effective. All
treatments had 96% or greater reduction of
suspended solids during the final runoff event.
The percent reduction in turbidity during
the first runoff event for the straw blanket
with PAM was 86%, compost blanket was
96%, compost blanket with PAM1 was 96%,
compost blanket with PAM2 was 98%, and
the compost blanket with Bio-Floc, the 2:1,
1:2, and wood mulch blankets were all 99%
effective. All treatments had 98% or greater
reduction of turbidity during the final run-
off event, with the exception of the compost
blanket which was 96% effective.
During the first runoff event, the straw
blanket with PAM contributed 8,000%
more TKN than the bare soil, the compost
blanket contributed 340% more, the 2:1 blan-
ket contributed 277% more, the 1:2 blanket
contributed 209% more, and the wood
mulch blanket released 18% more. While the
bare soil and the wood mulch blanket treat-
ments did not contribute any soluble P from
runoff, relative to the compost blanket, the
soluble P load from the straw blanket with
PAM was 3,800% greater, the 2:1 blanket
was 16% greater, and the 1:2 blanket was
41% less. Nitrogen and phosphorus load-
ing from mineral fertilizer used to establish
vegetation in conventional straw ECBs can
be a serious threat to receiving surface water
and should be addressed by the regulatory
community.
Under these site and environmental con-
ditions, any combination of compost and
mulch reduced runoff volume, peak runoff
rate, and soil loss relative to a straw blanket
with PAM. The greater the percent of com-
post used in an ECB, the lower the total
runoff, the greater the percent of rainfall
absorption, and the slower the runoff rate.
Conversely, the greater the percent of wood
mulch used in the erosion control blanket,
the lower the sediment and suspended sedi-
ment load. These results indicate that particle
size distribution, not necessarily wood mulch
or compost specifically, is probably the main
characteristic of an organic ECB that will
influence runoff and/or sediment loss. The
greater the percent of small particles, the
greater the ability to reduce runoff, but the
greater the percent of large particles, the
slower the runoff rate and the lower the sedi-
ment loss. This indicates that current particle
size distribution specifications for compost
ECBs probably have too great a percentage
of small particles and should be revised to
decrease soil loss.
Due to the extraordinary ability of compost
blankets to absorb rainfall and reduce storm
runoff, in the future they should be evaluated
as storm water reduction tools for construc-
tion and post construction soil applications.
Assigning appropriate runoff curve numbers
to compost blankets may assist hydrologic
engineers in reducing design footprints for
sediment retention, storm water manage-
ment, and bioretention ponds.
Acknowledgements
The authors would like to thank John Dow for his assistance
collecting water samples at the field site. They also thank
Lena Polyakova for her total suspended solids (TSS) analy-
sis at the Auburn University School of Forestry and Wildlife
Sciences Biogeochemical Laboratory.
413
nov | dec 2007 volume 62, number 6
References
Adams, J.E. 1966. Influence of mulches on runoff, erosion,
and soil moisture depletion. Soil Science Society of
America Proceedings 30:110-114.
AASHTO (American Association of State Highway and
Transportation Officials). 2003. Standard Specification
for Transportation Materials and Methods of Sampling
and Testing, Designation M10-03, Compost for Erosion/
Sediment Control. Washington, DC: AASHTO.
Brady, N.C., and R.R. Weil. 1996. The Nature and Properties
of Soils, 11th edition. Upper Saddle River, NJ: Prentice
Hall.
CONEG (Coalition of Northeast Governors). 1998. Standard
specification for compost use in erosion control. In Field
Evaluation of Source Separated Compost and Coneg
Model Procurement Specifications for Connecticut
DOT projects, ed. K.R. Demars, and R.P. Long, JHR
98-264. University of Connecticut and Connecticut
Department of Transportation.
Demars, K., R. Long, and J. Ives. 2000. Use of Wood
Waste Materials for Erosion Control. New England
Transportation Consor tium technical report NETCR
20. Project 97-3. Storrs, CT: University of Connecticut.
Demars, K.R., and R.P. Long. 1998. Field Evaluation of
Source Separated Compost and CONEG Model
Procurement Specifications for Connecticut DOT
Projects. JHR 98-264. University of Connecticut and
Connecticut Department of Transportation.
ECTC (Erosion Control Technology Council). 2004.
Standard Specification for Rolled Erosion Control
Products, revision 4904.
Epstein, E., W.F. Grant, and R.A. Struchtemeyer. 1966. Effects
of stones on runoff, erosion and soil moisture. Soil
Science Society of America Proceedings 30:638-640.
Federal Highway Administration. 1997. Erosion and sedi-
ment control, dirty work everyone should do. Greener
Roadsides 4(2):1.
Faucette, L.B. 2004. Environmental Benefits and Impacts of
Compost Systems and Industry Standard BMPs used
for Erosion Control in Construction Activities. 2004.
PhD Dissertation, Institute of Ecology, University of
Georgia.
Faucette, L.B., C.F. Jordan, L.M. Risse, M. Cabrera, D.C.
Coleman, and L.T. West. 2005. Evaluation of storm
water from compost and conventional erosion control
practices in construction activities. Journal of Soil and
Water Conser vation 60(6):288-297.
Foster, G.R., R.A. Young, M.J.M. Romkens, and C.A.
Onstad. 1985. Processes of soil erosion by water. In Soil
erosion and crop productivity, ed. R.F. Follett and B.A.
Stewart, 137-162. Madison, WI: Agronomy Society of
America, Crop Science Society of Amer ica, and Soil
Science of America.
GDOT (Georg ia Department of Transportation). 2004.
Georgia Department of Transportation Construction
Manual, Erosion Control. Section 700.3.05-D
—Grassing. http://tomcat2.dot.state.ga.us/thesource/
construction/index.html.
Georgia Soil and Water Conservation Commission. 1993.
Manual for Erosion and Sediment Control in Georgia.
6:19-191.
Georgia Soil and Water Conservation Commission. 2002.
Erosion and Sediment Control. Course Manual.
Glanville, T.D., R.A. Persyn, and T.L. Richard. 2001. Impacts
of compost application on highway construction
sites in Iowa. Presented at 2001 American Society of
Agricultural Engineers Annual International Meeting.
Sacramento, CA. Paper No. 01-012076.
Gorman, J.M., J.C. Sencindiver, D.J. Horvath, R.N. Singh,
and R.F. Keefer. 2000. Erodibility of fly ash used as a
topsoil substitute in mineland reclamation. Journal of
Environmental Quality 29:805-811.
Granberry, D., W. Kelly, D. Langston, K. Rucker, and
J. Diaz-Perez. 2001. Testing compost value on pepper
plants. BioCycle: Journal of Composting & Organics
Recycling 42:10.
Indiana Department of Natural Resources. Indiana
Handbook for Erosion Control Revisions. Section
702.08 Compost Mulching.
Kirchhoff, C.J., J. Malina, and M. Barrett. 2003. Character istics
of Composts: Moisture Holding and Water Quality
Improvement. Federal Highway Administration/TX
DOT-04/0-4403-2.
Laflen, J.M., J.L. Baker, R.O. Hartwig, W.A. Buchele, and H.P.
Johnson. 1978. Soil and water loss from conservation
tillage systems. Transactions of ASAE 21:881-885.
Lyle, E.S. 1987. Surface mine reclamation manual. New York,
NY: Elsevier.
Maynard, A. 2000. Applying leaf compost to reduce fertil-
izer use in tomato production. Compost Science and
Utilization 3:203-209.
Meyer, L.D., C.B. Johnson, and G.R. Foster. 1972. Stone
and woodchip mulches for erosion control on con-
struction sites. Journal of Soil and Water Conservation
27:264-269.
Meyer, L.D. 1985. Interrill erosion rates and sediment char-
acteristics. Transactions of ASAE 29:948-955.
Mukhtar, S., M. McFarland, C. Gerngross, and F. Mazac. 2004.
Efficacy of Using Dairy Manure Compost as Erosion
Control and Revegetation Material. 2004 American
Society of Agricultural Engineers/Canadian Society of
Agricultural Engineers Annual International Meeting,
Ontario, CA. Paper No. 44079.
Risse, M., and B. Faucette. 2001. Compost Utilization for
Erosion Control. University of Georgia Cooperative
Extension Service Bulletin 1200. Athens, GA:
Cooperative Extension Service, University of Georgia.
SAS, 2001. SAS System 8.2 for Microsoft Windows. Cary,
NC: SAS Institute.
Sims, G.K., T.R. Ellsworth, and R.L. Mulvaney. 1995.
Microscale determination of inorganicnitrogen in water
and soil extract. Communications in Soil Science and
Plant Analysis 26:303-316.
Texas Department of Transportation. Item 161.2 Materials
and Physical Requirements for Erosion Control
Compost.
US Composting Council. 1997. Test Methods for the
Examination of Composting and Compost. Amherst,
OH: United States Composting Council.
USEPA (US Environmental Protection Agency). 1983.
Methods for chemical analysis of water and wastes,
EPA-600/4 4-79-020. Cincinnati, OH: United States
Environmental Protection Agency.
USEPA. 1997. Innovative Uses of Compost: Erosion Control,
Turf Remediation and Landscaping. EPA 530-F-97-043.
Washington, DC: USEPA.
USEPA. 1999. Standard operating procedure for the analy-
sis of residue, non-filterable (suspended solids) water.
Method 160.2NS. Chicago, IL: Region 5 Central
Regional Laboratory, USEPA.
USEPA. 2000. Bosque watershed doesn’t waste manure.
Nonpoint Source News Notes 63:21-22.
USEPA. 2006. Compost Blanket: Construction Site
Storm Water Runoff Control. National Menu of Best
Management Practices for Construction Sites, National
Pollution Discharge Elimination System Phase II.
Washington, DC: USEPA.
USDA Soil Conservation Service (USDA SCS). 1968.
Soil Survey Clarke and Oconee Counties, Georgia.
Washington, DC: USDA SCS.
US Department of Commerce, National Weather Service.
1961. Technical paper No. 40 of the National Weather
Service. http://www.erh.noaa.gov/er/hq/Tp40s.htm.
Vleeschauwer, D.D., and M.D. Boodt. 1978. The com-
parative effects of surface applications of organic mulch
versus chemical soil conditioners on physical and chem-
ical properties of the soil and on plant growth. Catena
5:337-349.
Weather Channel. 2005. Local Weather for
Athens, GA (30602): Averages and Records
for Athens, GA (30602). http://www.weather.
com/weather/climatology/monthly/30602.
Wischmeier, W.J., and D.D. Smith. 1978. Predicting
Rainfall Erosion Loss—A Guide to Conservation
Planning, Agricultural Handbook No. 537, Washington
DC: USDA.
... Mulching practices for agricultural lands have been widely conducted around the world due to the achievement of significant reductions of runoff generation and sediment yield (Blanco-Canqui et al. Cook et al., 2006;Faucette et al., 2007;Jordán et al., 2010;Mostaghimi et al., 1988;Poesen and Lavee, 1991). García-Orenes et al. (2009) reported that application of straw mulch not only significantly improved soil properties during a 16-month period, but also effectively prevented soil and water losses from undergoing the 5-year return period rainfall simulation events. ...
... However, immediate or short-term application of stalk mulch rarely altered the physicochemical properties of soils (Prosdocimi et al., 2016). Hence, the variations of runoff and sediment yield in the plots with and without cornstalk mulch were directly linked to different hydrological responses (Cook et al., 2006;Faucette et al., 2007). The stalk mulch causes reductions of runoff generation and sediment yield as the delayed runoff initiation, increase in hydraulic roughness, interception and infiltration and decline of raindrop impact on the surface soil within various coverage rates (García-Moreno et al., 2013;Wang et al., 2014). ...
Article
Dissolved carbon plays a pivotal role in carbon cycles and potentially affects ecological processes of water body. While stalk mulch can regulate soil and water losses, its effects on the export of dissolved carbon from soils are poorly understood. The main objective of this study was to determine the effects of rainfall intensity and downslope cornstalk mulch (the lengths of cornstalks along the slope, DCM) on runoff, sediment yield and dissolved carbon losses, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and dissolved total carbon (DTC). A series of field rainfall simulations were conducted on the steep fallow land (20 °) locating in a representative hillslope of southwestern China that experiences severe soil erosion, and data for runoff, sediment and dissolved carbon loss rates were obtained from triplet parallel plots (1.5 m long and 1 m wide for each one) using 60 min rainfall simulations at 30 and 90 mm h −1 intensities on bare soils and 90 mm h −1 intensity on soils with DCM (air-dried whole plants, 60% coverage and weight 1.65 kg), respectively. Rainfall intensity showed positive effects on runoff generation, sediment yield and loss rates of DIC, DOC and DTC. The plots with immediate DCM had no difference in runoff generation, but were 71.1% lower in sediment yield and 53.9% higher in DOC loss rate relative to the bare plots. The contribution of DIC to DTC increased from 35.9% to 59.6% with the increasing rainfall intensity. Cornstalk mulching appeared efficient in reducing sediment yield, but its adoption is likely to dramatically enhance DOC exports from soils with concerns for the quality of inland waters. Further research studies are required to discriminate between soil and cornstalk mulch contribution to DOC exports by overland flow.
... In the case of helimulching, if the straw is not sufficiently broken up and evenly distributed during application, it can also form clumps, promoting erosion in between them and also limiting the development of vegetation (deWolfe et al., 2008). On the other hand, wood-residue mulches are more resistant to the aforementioned factors and the heterogeneity in size provides diverse protection mechanisms, as the materials absorb rainfall impact and also trap and reduce the movement of sediments (Faucette et al., 2007). Hydromulches are also a good option for treating short steep and exposed slopes because they bind with the soil, being more resistant to wind and water, but are known to decompose quickly, usually within the first post-fire year thus reducing their effectiveness, and their application is rather expensive (Hubbert et al., 2012;Prats et al., 2016b;Robichaud et al., 2013b). ...
Article
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Wildfires are known to be one of the main causes of soil erosion and land degradation, and their impacts on ecosystems and society are expected to increase in the future due to changes in climate and land use. It is therefore vital to mitigate the increased hydrological and erosive response after wildfires to maintain the sustainability of ecosystems and protect the values at risk downstream from the fire-affected areas. Soil erosion mitigation treatments have been widely applied after wildfires but assessment of their effectiveness has been limited to local and regional-scale studies, whose conclusions may depend heavily on site-specific conditions. To overcome this limitation, a meta-analysis approach was applied to investigations of post-wildfire soil erosion mitigation treatments published in peer-reviewed journals. A meta-analysis database was compiled that consisted of 53 and 222 pairs of treated/untreated observations on post-fire runoff and erosion, respectively, extracted from 34 publications indexed in Scopus. The overall effectiveness of mitigation treatments, expressed as the quantitative metric ‘effect size’, was determined for both the runoff and erosion observations, and further analyzed for four different types of treatments (cover-based, barriers, seeding, and chemical treatments). The erosion observations involving cover-based treatments were analyzed for differences in effectiveness between 3 different types of mulch materials (straw, wood-based, and hydromulch) as well as between different application rates of straw and wood materials. Finally, the erosion observations were also analyzed for the overall effectiveness of post-fire year, burn severity, rainfall amount and erosivity, and ground cover. The meta-analysis results show that all four types of treatments significantly reduced post-fire soil erosion, but that only the cover and barrier treatments significantly reduced post-fire runoff. From the three different cover treatments, straw and wood mulches were significantly more effective in mitigating erosion than hydromulch. In addition, the effectiveness of both straw and wood mulches depended on their application rates. Straw mulching was less effective at rates below than above 200 g m⁻², while mulching with wood materials at high rates (1300 to 1750 g m⁻²) produced more variable outcomes than lower rates. Results also suggest that the overall effectiveness of the treatments was greatest shortly after fire, in severely burned sites, providing or promoting the development of ground cover over 70%, and that it increased with increasing rainfall erosivity. It can be concluded that, in overall terms, the application of the studied post-fire erosion mitigation treatments represented a better choice than doing nothing, especially in sites where erosion is high. However, the meta-analysis highlights under-representation of studies on this topic outside of the USA, Spain and Portugal. It was also observed that most of the studies were conducted at hillslope scale and tested mulching (namely straw, wood and hydromulch) and/or barriers, while larger scales and other treatments were scarcely addressed. Further efforts need to be made in testing, from field and modeling studies, combinations of existing and/or emerging erosion mitigation treatments to ensure that the most adequate measures are applied after fires.
... 67 Traditionally, topsoil is used as the erosion control layer material in landfill covers. 68 However, compost can be an alternative erosion control product in these systems, mostly due to 69 its internal skeletal structure, water retention capability, and nutrient content which allows for 70 superior vegetative facilitation (Kirchhoff et al. 2003;Faucette et al. 2007Faucette et al. , 2009. In a rainfall 71 event, raindrop impact is a significant contributor of soil erosion. ...
Technical Report
Landfill covers are required by federal regulations to cap the municipal solid waste and to prevent leachate formation. The use of compost as part of a vegetative layer in landfill final covers is one way to improve the sustainability of landfills. In order to successfully use compost in landfill cover applications, hydraulic compatibility of the compost and underlying geotextile filters must be adequate. The hydraulic compatibility of various composts and geotextiles have been explored through laboratory long-term filtration (LTF) tests. Upon completion of the LTF tests, particle size analyses, permittivity tests, piping measurements, and image analyses were conducted to evaluate clogging and retention performances. When the clogging ratios and piping measurements were considered, all compost-geotextile combinations yielded acceptable clogging and retention performance. A parametric study was conducted to determine if different characteristic pore sizes and grain sizes influenced the laboratory clogging ratios, and showed no apparent relationship. Existing filter selection criteria successfully predicted the observed retention behavior but failed to predict the clogging behavior. Based on limited LTF data, compost is not likely to promote clogging in geotextiles; however, additional soil-geotextile filtration tests are necessary to propose a new filter criterion for clogging.
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This manuscript describes the natural soil amendments used in agriculture, which are divided into three groups: organic, organic-mineral, and mineral amendments. It also describes less popular agents, such as clay minerals, sewage sludge, and amendments based on slaughterhouse wastes. A specific group of organic amendments are algae-base amendments which are becoming more and more popular. The soils most improved with natural amendments include sandy loam and clay soils. Natural organic amendments are best used on light soils that are poor in organic matter and nutrients (NPK). Whereas mineral amendments can be used as fertilizers (provide mainly Si, Ca and Al) or to restore degraded soils. Based on the analyzed literature, natural soil amendments may well be considered as an alternative to synthetic agricultural agents.
Thesis
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A variety of environmental problems like soil erosion, landslides depletion in the water bodies, diversity of flora and fauna, etc., have been inducted into the eco-system. Especially, the nutrient rich soil top is taken away by the erosion which results in crucial environmental degradation, particularly, in sloppy terrain regions. The process of soil erosion greatly influences Eutrophication in water bodies like, rivers, ponds, lakes and etc., which leads to un-integrated water resource management. The accumulation of sediments, which is the consequence of soil erosion, has been considerably promoting the declination and deterioration of the storage capacity of as many as forms of water bodies. The predominant accelerating factor due for soil erosion known is the slope topography and the amount, intensity & frequency of rainfall and wind velocity, temperature and etc, are the further factors of influence. The primary objective of the current research is to study and discover the appropriate soil stabilization strategies for Thekkumalai Hill Base, Kanyakumari District, TamilNadu, India, which is anticipated to be soil erosion prone zone. Hence, the secondary objective of the present study is to give a light for the integrated water resource management with the discovered mechanism in the chosen area which is primarily an agri-fed zone in the district. The physical characteristics of soil, such as particle size, gradation, specific gravity, maximum dry unit weight, Atterberg limits and shear strength were examined with the samples collected from 13 different locations where deeper and wider gullies were found, in order to, identify the rate of soil erodibility in the study area. It was found that samples from all 13 study locations were of Sandy Clay Loam (SCL) type soil as the samples had more than 60% of grains were greater than 75µ and the remaining were less than that amount. Ranks and weights were assigned to different erosion influencing factors with the above findings from the study area using Analytical Hierarchy Process (AHP). The relative significance of an influencing factor of erosion is assumed to be weight, whereas the ranks were assigned to each factor. Thus, the vulnerability of soil erosion in the chosen study area has been assessed and the necessary thematic maps were prepared by integrating Weight and Rank method and using GIS. Consequently, the chemical properties such as Soil pH, Electric Conductivity (EC) and the total concentration of Nitrogen (N), Phosphorous (P) and Potash (K) were examined, in order to determine, the nutrient index of samples. As a result of this, it was found that more than half of the samples were moderately alkaline and the rest were slightly or moderately acidic, while all the samples were low in Calcium Carbonate (CaCO3). The Electric Conductivity in the entire study area was found to be in good status and a higher loss of nutrients and depletion of soil fertility was indicated by the nutrient index of the samples. An innovative erosion control mechanism using the combination of Rice Husk Ash (RHA), Lime and Red Mud as the stabilizing agents has been proposed as the necessary percentages of samples were found to be with clay content. It is proposed to use the above agents actually to utilize the advantage of adhesive tendency of the clay content to be adhered. The experimental results of the proposed mechanisms illustrated a significant improvement in Unconfined Compressive Strength Value and California Bearing Ratio value of the stabilized samples in comparison to those of the original samples. It is also proposed that the erosion can be controlled by augmenting the protective cover of the regional terrain as the chosen study area is a hilly base with a slope more than 2.5 degree. Five different experimental protective covers were tested to create a barrier to the erosion with agents namely: Sweet gum ball, Rip rap, Bermuda grass with Polyacrylamide (PAM), Coconut shell with mulch which are widely and cheaply available in the study area. Five different rills were created with the above agents and the periodical visual observations were made in comparison with untreated rills (Control). The degree of erosion control by different agents were compared and documented which authentically proved to slow down the runoff rate. The present study statistically and evidently prove that the proposed stabilization mechanisms brought a tremendous improvement in the strength of SCL type soil in the study area which shall spontaneously result in soil stabilization and the integrated water resource management.
Article
Erosion management is a major environmental challenge facing highway construction. A research study was undertaken to analyze possible sustainable improvements to current standard procedures for final grade turfgrass establishment on disturbed lands at both field and greenhouse scale. Pure compost, biosolids and greenwaste, and two topsoil/compost blends were compared with a topsoil standard (with additional straw and fertilizer application) in their ability to reduce sediment and nutrient runoff and improve green vegetation (GV) establishment. Differences in field GV rates were only observed during initial establishment (biosolids and topsoil had 11%–35% greater GV). This period coincided with an initial flush of nutrients and sediment that was 3- to 17-fold greater than later phase runoff. After this initial runoff phase, tested materials exported largely comparable nutrient and sediment runoff. In the controlled greenhouse studies, only the biosolids treatment reduced runoff volume, by 40%–98%, compared to the standard practice. Evidence of soil sealing from rainfall impact was seen for topsoil/compost mixtures, resulting in 20- to 28-fold greater total runoff volume and 28- to 224-fold greater sediment export than topsoil. Compost addition increased nutrient export 1.5- to 51-fold and 2.2- to 3.3-fold for phosphorus and nitrogen, respectively, due to increased runoff concentrations (pure compost) or volume (topsoil/compost mixtures). It was hypothesized that the additional straw mulch layer for the standard topsoil offered increased surface resistance and physical protection from rainfall impact and surface flow compared to the nonmulched compost treatments. Inclusion of a straw mulch layer with compost may provide similar, or better, slope stability performance.
Article
The amount of municipal solid waste (MSW) generated in the US increases every year, and about 30% of the MSW generated is either recyclable or compostable. Utilization of compost-amended topsoils as a vegetative layer on highway slopes contributes to large-volume beneficial reuse of these materials. This study examines the shear and hydraulic properties of two types of composts, biosolids and leaf compost, and their blends with a topsoil for their potential use on highway slopes. Direct shear and consolidated-undrained triaxial shear tests were performed to obtain the shear strength parameters. Flexible-wall hydraulic conductivity tests and unsaturated hydraulic tests were performed to evaluate the saturated and unsaturated hydraulic behavior of the materials, respectively. Compost addition resulted in an increase in effective friction angle, whereas modest changes were observed in effective cohesion, total cohesion, and total friction angle of the topsoil. Two shape parameters determined via digital image analysis, angularity and relative form of 2-dimensional images, correlated well with the measured effective friction angles of the materials tested. Compost treatment resulted in an increase in saturated hydraulic conductivity and the plant-available water content. Unsaturated hydraulic conductivities of all materials were comparable at the matric potential of field capacity (10 kPa), and the compost-amended topsoils experienced 1–3 orders of decrease in their unsaturated hydraulic conductivities during the drying process.
Article
Soil coverage with straw and plastic mulch is a valuable and useful strategy for enhancing crop production in arid regions. However, a better understanding of the mechanism by which this innovative practice drives spatial and temporal variation in soil temperature and water content and improves crop production could guide cropping system optimization. A three-year field experiment was performed with four wheat-maize strip-intercropping treatments: 1) no-tillage with 25−30 cm tall wheat straw standing in wheat strips and residual plastic mulching in maize strips (NTS), 2) no-tillage with 25−30 cm tall wheat straw mulching in wheat strips and residual plastic mulching in maize strips (NTM), 3) conventional tillage with 25−30 cm tall wheat straw incorporation in wheat strips and annual new plastic mulching in maize strips (CTS), and 4) conventional tillage without wheat straw retention in wheat strips and annual new plastic mulching in maize strips (CT). The temporal and spatial variation in soil temperature and soil water content was assessed. NTM had the greatest soil water retention, and increased soil water content in the 0−120 cm soil depth by 6.4, 5.2, and 5.4 % at the wheat independent growing period, intercrops co-growing period, and maize independent growing period, respectively, compared with CT. In the 0−15 cm soil depth, compared with CT, NTS decreased soil temperature by 0.73, 1.18, and 0.85 °C, NTM decreased it by 1.35, 1.95, and 1.38 °C, during the three aforementioned crop growing periods. With the intercropping treatment, soil temperature in the 0−15 cm soil depth of maize strips was higher than that of wheat strips with NTS by 1.13, 3.67, and 1.44 °C, and with NTM higher by 1.32, 2.97, and 1.75 °C, especially higher as 1.38, 4.00,and 1.68 °C with CT, during the three aforementioned crop growing periods. According to the value of difference between air and soil temperatures, NTM maintained soil heat in the low temperature season and reduced soil temperature in the high temperature season. These allowed the intercrops to grow in a collaborative state with the NTM treatment during their growing period, it is an important regulation mechanism for growth and development of intercropped wheat and maize. NTM improved total grain yield of wheat plus maize by 14.9 % in comparison to CT. The optimized soil temperature and increased soil moisture for the intercrops’ strips with NTM indicates that the integrated set of practices in this treatment can be used as a superior technique to overcome simultaneous water shortage and heat stress in arid irrigated areas of northwestern China.
Book
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Thoroughly updated and now in full color, the 15th edition of this market leading text brings the exciting field of soils to life. Explore this new edition to find: A comprehensive approach to soils with a focus on six major ecological roles of soil including growth of plants, climate change, recycling function, biodiversity, water, and soil properties and behavior. New full-color illustrations and the use of color throughout the text highlights the new and refined figures and illustrations to help make the study of soils more efficient, engaging, and relevant. Updated with the latest advances, concepts, and applications including hundreds of key references. New coverage of cutting edge soil science. Examples include coverage of the pedosphere concept, new insights into humus and soil carbon accumulation, subaqueous soils, soil effects on human health, principles and practice of organic farming, urban and human engineered soils, new understandings of the nitrogen cycle, water-saving irrigation techniques, hydraulic redistribution, soil food-web ecology, disease suppressive soils, soil microbial genomics, soil interactions with global climate change, digital soil maps, and many others Applications boxes and case study vignettes bring important soils topics to life. Examples include “Subaqueous Soils—Underwater Pedogenesis,” “Practical Applications of Unsaturated Water Flow in Contrasting Layers,” “Soil Microbiology in the Molecular Age,” and "Where have All the Humics Gone?” Calculations and practical numerical problems boxes help students explore and understand detailed calculations and practical numerical problems. Examples include “Calculating Lime Needs Based on pH Buffering,” “Leaching Requirement for Saline Soils,” "Toward a Global Soil Information System,” “Calculation of Nitrogen Mineralization,” and “Calculation of Percent Pore Space in Soils.”
Article
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Soil erosion is considered the biggest contributor to nonpoint source pollution in the United States according to the U.S. Environmental Protection Agency and the federally mandated National Pollution Discharge Elimination System. Soil loss rates from construction sites can be 10 to 20 times that of agricultural lands. The use of surface applied organic amendments has been shown to reduce runoff and erosion, however, with the exception of animal manure, little research has focused on nutrient loss from these amendments. 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. A rainfall simulator applied rainfall at an average rate equivalent to a 50 yr hr1 storm event (7.75 cm hr1). Three simulated rain events were conducted: immediately after treatment application, at three months when vegetation was established, and at one year when the vegetation was mature. After three months, the compost generated five times less runoff than hydroseed with silt fence, and after one year, generated 24 percent less runoff. All treatments proved better than the control at reducing solids loss. Total solid loads were as much as 3.5 times greater from hydroseed and silt fence compared to the composts during the first storm, and as much as 16 times greater during the second storm. Materials high in inorganic nitrogen (N) released greater amounts of nitrogen in storm runoff; however, these materials showed reduced N loss over time. Hydroseeding generated significantly higher total phosphorus (P) and dissolved reactive P loads compared to compost in storm runoff during the first storm event.
Conference Paper
Full-text available
Runoff, interrill erosion, and growth of erosion control vegetation and weeds were measured on conventionally treated portions (control) of newly constructed roadway embankments, and on areas pretreated with topsoil or one of three different types of composted organics. Runoff rates and interrill erosion rates from the control and topsoil-treated plots were highest. Runoff rates from the three compost media (biosolids, yard waste, bio-industrial waste) used were statistically lower than the control. Runoff from plots treated with yard waste and bio-industrial waste composts were statistically lower from plots treated with topsoil. Interrill erosion rates from topsoil-treated plots were significantly higher than from compost-treated or control plots. The amounts of planted cover crop grown on all treatments were statistically indistinguishable. Mean values for weed growth on the control and topsoil plots are statistically indistinguishable, and all compost treatments except biosolids-10 cm and yard waste-5 cm produced significantly lower weed growth than either the topsoil or control plots.
Article
Rill and interill (sheet) erosion are widespread but not as easy to recognise as gullies. Rill erosion can be evaluated visually when it is especially serious, but interill erosion is usually so inconspicuous that it must be evaluated experimentally. -K.Clayton
Conference Paper
In a simulated rainfall study, first flush (one liter) and the remaining runoff samples were collected from 12 non-vegetated and isolated field plots established on a 3:1 embankment constructed as a road right-ofway. These plots were assigned to four treatments namely compost manufactured topsoil (CMT); 2.5 cm of dairy manure compost (DMC) incorporated into 8-cm of topsoil, erosion control blanket (ECC); a 5-cm layer of DMC and woodchips blended (2.5 cm each mixed by volume) and applied on top of the undisturbed soil, agronomic rate compost (ARC); DMC broadcast at 39.5 t/ha, and commercial fertilizer (CF); broadcast at the rate of 112kg N /ha, 49 kg P /ha, and 83 kg K /ha, respectively. The ECC plots had smaller total runoff mass than all other treatments and significantly lower TS and TSS in the runoff as compared to those in the runoff from CF plots. Overall, plots amended with DMC or DMC/woodchips blend, though much higher in N, P and K, produced less runoff and sediment and nutrients in the runoff as compared to the mineral fertilizer plots without any organic amendment. It was concluded that ECC and CMT treatments established to control erosion and revegetate, respectively, a newly constructed road-right-of-way and shortly there after, subjected to rain (a worst case scenario) will be effective in erosion control. Even though compared to the CF treatment, generally smaller quantities of N, P and K were measured in the runoff from ECC and CMT treatment plots, N and P concentrations in the runoff were high from the standpoint of water quality.
Article
A rainfall simulator was used to evaluate the effects of six different tillage practices on soil and water losses from continuous corn for three soils in Iowa. Soil loss decreased as tillage decreased. Percent of soil covered by corn residue explained between 78 and 89 percent of the variance in erosion among tillage systems. The effect of non-uniformly distributed corn residue on controlling erosion was greater than expected based on a published mulch factor.
Article
For two consecutive years, one-inch (50 T/A) of leaf compost was applied to plots on a sandy terrace soil (Windsor, Connecticut) and a loamy upland soil (Mt. Carmel, Connecticut). These compost-amended plots were fertilized with 10-10-10 (N-P2O5-K2O) at three rates: 0, 650 (half), 1300 (full) lb/A and cottonseed meal at a rate of 2166 lb/A. Tomato (Lycopersicon esculentum Miller) yield from compost-amended plots were compared to yield from unamended control plots fertilized with 1300 lb 10-10-10/A. In both years, at both sites, plots only amended with compost had yields equivalent to the fertilized control plots. In both years, the greatest yields at Mt. Carmel were from plots amended with compost and the full rate of inorganic fertilizer. In the second year, yields from compost-amended plots fertilized at half the rate were equivalent to compost-amended plots fertilized at full rate. The yields from the organic plots were similar to the control plots the first year and to plots amended with compost and half the rate of fertilizer the second year. At Windsor, the greatest yields for both years were from plots amended with compost and the full rate of fertilizer. The compost-amended plots fertilized with cottonseed meal produced the lowest yields, both years. Cumulative effects of compost on soils were measured by increases in pH and organic matter percentage at both sites. Tomato fruit in plots amended with compost and no fertilizer developed less blossom-end rot than fruit in all other treatments.
Article
Scientific planning for soil and water conservation requires knowledge of the relations between those factors that cause loss of soil and water and those that help to reduce such losses. The soil loss prediction procedure presented in this handbook provides specific guidelines which are needed for selecting the control practices best suited to the particular needs of each site. The procedure is founded on an empirical soil loss equation that is believed to be applicable wherever numerical values of it factors are available. KEYWORDS: TROPAG textbar Miscellaneous subjects textbar Climatology textbar Land Conservation and Management textbar USA (Mainland).