Evaluation of Native Grass Sod for
Stabilization of Steep Slopes
Presented by:
Kenley Stone
M.S. Thesis Defense
Overview
Factors and concerns of erosion
 Common methods used to control erosion
 Literature Review
 Native Sod
 Hypotheses & Objectives
 Methods
 Data Collection
 Data Analysis
 Results

Factors that Accelerate
Erosion in Landscapes
Removal of
vegetation
 Disturbed riparian
ecosystems
 Steep slopes
 Arid conditions
 Phyto-toxic soil

Problems Associated with Erosion



Landslides/Mudslides
Sedimentation of
rivers and streams
Degraded water
quality
Common Methods Used to Control
Erosion on Steep Slopes
 Broadcast
seeding
 Drill seeding
 Hydroseeding/Hydromulch
 Straw-coconut fiber blanket
 Rip-rap
Broadcast Seeding and Drill-Seeding
Hydroseeding & Rip-Rap
Rip-rap
Straw-Coconut Fiber Blanket
Literature Review
Sodding is one of the most effective means of
controlling erosion and preventing sedimentation
damage (NCDWQ 1997).
It has been shown that sod can remove up to 99%
of the total suspended solids in runoff (USEPA
2002).
Using simulated rainfall, sod reduced runoff rates
54-59% more compared to the other treatments
that included wood excelsior, jute fabric, coconut
fiber blanket, coconut strand mat, and straw
(Krenitsky et. al. 1998).
In Montana, Jensen and Sindelar (1979) concluded
that if a large scale sodding machine could be
developed, dryland sodding will become a highly
desirable soil stabilization treatment.
Native Sod




Western wheatgrass
(Agropyron smithii)
Idaho fescue
(Festuca idahoensis)
Thickspike wheatgrass
(Agropyron dasystachym)
Canada bluegrass
(Poa compressa)
Potential Merits of Native Sod




Immediately enhances
aesthetic values of an
area
Provides immediate
stabilization of steep
slopes
Can reduce runoff and
sediment loss
Can reduce noxious
weed invasion
Hypothesis & Objectives
H1: Native sod will produce
significantly greater production and
cover compared to other treatments.
Objective1: Measure plant growth
characteristics on slopes treated with
native sod compared to other plant
establishment methods.
Hypotheses and Objectives-Cont’d
H2: Native sod will be more effective
at controlling erosion than the other
treatments
Objective2: Determine runoff,
sediment yield, and infiltration of
slopes treated with native sod
compared to other plant
establishment methods
Hypotheses and Objectives-Cont’d
H3: RUSLE2 will predict sediment loss
to be less on slopes treated with
native sod compared to the other
treatments
Objective3: Model sediment yield on
slopes treated with native sod
compared to other plant
establishment methods using RUSLE
version 2.0.
Hypotheses and Objectives-Cont’d
H4: Costs of native sod will initially
exceed those of the other
treatments, but will not need
maintenance in the future
Objective4: Evaluate the cost of using
native sod for steep slope
reclamation compared to other plant
establishment methods
Methods
Study Sites
Highway Fill
Mine Waste
Ski Slope
Highway Fill Site Description
Located 20 km west
of Bozeman
 South facing road fill
 40% slope, loam
 Plant establishment
and erosion control
on similar sites has
been difficult

Treatments on the Highway Fill
Broadcast
Seed/Hydromulch
Native Sod
3 replications
Plot dimensions: 3.2 x 9.1 meters
Broadcast Seed/
Straw Blanket
Native Sod Mix
(All three sites)
 Western
wheatgrass (Agropyron
smithii)
 Idaho fescue (Festuca idahoensis)
 Thickspike wheatgrass (Agropyron
dasystachyum)
 Canada bluegrass (Poa compressa)
Broadcast Seed Mix
(Highway Fill & Mine Waste)
Variety & Species









Slender-Pryor (Agropyron tracycaulum)
Thickspike-Critana (Agropyron dasystachyum)
Western-C) Rosana (Agropyron smithii)
Bluebunch-C) Secar (Agropyron spicatum)
Green Needlegrass-Lodorm (Stipa viridula)
Bluegrass, Big-C) Sherman (Poa ampla)
Fescue, Sheep-Covar (Festuca Ovina)
Coneflower, Yellow Prairie-V.N.S. (Rudbeckia fulgida)
Bee Plant, Rocky Mountain-V.N.S (Cleome serrulata)
Highway Fill
2003
2004
Ski Slope Site Description
Located at the
Yellowstone Club, Big
Sky, MT
 A north facing skislope with a 35%
gradient
 Clay loam
 Previous attempts at
grass establishment
and erosion control
failed

Treatments on the Ski Slope
 Native
Sod
 Broadcast Seed with straw-coconut
fiber blanket
 Broadcast Seed
Three replications
Plot dimensions: 3.2 x 9.1 meters
Broadcast Seed Mix
(Ski Slope)
 Pryor-Slender
wheatgrass
(Agropyron trachycaulum)
 Mountain brome (Bromus carinatus)
 White yarrow (Achillea millefolium)
 Orchard grass (Dactylis glomerata)
 Hard fescue (Festuca trachyphylla)
 Canada bluegrass (Poa compressa)
Ski Slope
2003
2004
Mine Waste Site Description
Located
approximately 30 km
west of Helena
 Abandoned mine spoil
on a 70% slope
 pH 3.4, sandy loam
 Prior attempts at
grass establishment
and erosion control
failed miserably

Treatments on Mine Waste Site
 Broadcast seed with straw-coconut fiber
blanket implemented by the USFS 3
years ago
 Broadcast seed with straw-coconut fiber
blanket installed in 2003
 Native sod
 Redtop sod (Agrostis stolonifera)
Three replications
Plot dimensions: 3.2 x 10 meters
Mine Waste Site
2003
2004
Data Collection
Plant Growth
Characteristics
 Rainfall
Simulation/Sediment
and Runoff
Measurements
 Model Sediment Loss
Using RUSLE
 Cost Analysis

Plant Growth Characteristics
Above Ground
Biomass Production
 Percent Basal Cover
 Percent Canopy Cover
 Percent Ground Cover

Runoff & Sediment Yield at the
Highway Fill Site
A Meeuwig rainfall
simulator was used
to create a peak 10
year, 24 hour
storm event on
each plot
 Runoff and
sediment were
channeled to a
collection trough
and measured

Key Inputs of RUSLE
Rainfall/Runoff
 Erosivity Index
 Soil Erodibility
 Slope Length and
Gradient
 Cover Management

Eroded Hillslope
Data Analysis
 Two
way Analysis of Variance using
Sigma Stat
– Determined whether there is a significant
difference between means of treatments
and replications at a p-value of 0.05
– Student-Newman-Keuls Method
Parameters:
Basal, Canopy & Ground Cover, Production,
Sediment Yield, Runoff, Infiltration
Highway Fill Results 2004
(Perennial Grass)
Treatment
Native Sod
Broadcast Seed/
Straw Blanket
Broadcast Seed/
Hydromulch
Mean Production
(kg/ha)
748 a
286 b
102 b
Mean Canopy
Cover (%)
31.4 a
5.8 b
2.5 b
Ski Slope Results 2004
(Perennial Grass)
Treatments
Native
Sod
Broadcast Seed/
Straw Blanket
Broadcast
Seed
Mean Production
(kg/ha)
1488 a
509 a
662 a
Mean Canopy
Cover (%)
68.2 a
21.8 b
19.8 b
Mine Waste Results 2004
(Perennial Grass)
Treatments
Native
Sod
Redtop
Sod
Straw Blanket
Installed
2003
2001
Mean Production
(kg/ha)
631 a
417 ab
0b
138 ab
Mean Canopy
Cover (%)
28.8 a
18.8 a
0b
2.4 b
Sediment & Runoff
Results on the Highway Fill
b
400
300
Sedim ent Loss
200
(kg/ha)
a
100
a
0
Native Sod
Broadcast
Seed/Straw Blanket
Broadcast
Seed/Hydromulch
b
16
14
% Runoff
(runoff/precipitation
applied) * 100
12
10
8
6
a
4
a
2
0
Native Sod
Broadcast Seed/Straw
Blanket
Broadcast
Seed/Hydromulch
RUSLE2 Results
Native Sod
RUSLE2 Results-Cont’d
Broadcast Seed/Straw Blanket
RUSLE2 Results-Cont’d
Broadcast Seed/Hydromulch
Cost Analysis Results
Treatment
Native
Sod
Total Costs $34,216
Broadcast
Seed/Straw
Blanket
Broadcast
Seed/
Hydromulch
$17,178
$4,051
*Estimated over a 1 hectare sloped area with a 100 km mobilization distance
Potential Applications
of Native Sod

Sensitive Areas
– Steep slopes
– Riparian areas
– Channels and
drainage ditches
– Ski slopes
– Highway cuts
Acknowledgements
I thank Bitterroot Turf Farms,
Corvallis, MT. for funding a notable
portion of this research, propagating
the native grass, and providing
installation support during test plot
development. Special thanks is due
to the Montana Department of
Transportation, Helena, MT. , most
notably Mr. Phil Johnson, for providing
funds for this research and technical
support during test plot implementation
and report preparation. I thank the U. S. Forest Service, Helena,
MT. , specifically Duane Harp and Lois Olsen, for providing
support during test plot development. I also thank Mr. Bill
Hartsog who facilitated access to the Yellowstone Club, Big Sky,
MT. and provided support during test plot implementation. I
gratefully acknowledge the efforts of Melissa Mitchem, MSU
graduate student, for the support provided during field data
collection.