Specifying Soils for Complex Landscapes presentation outline

1
Specifying Soils for Complex Landscapespresentati
on outline
Soil Design Strategies Natural vs Blended
Simple vs Complex Specifying Blended Soils
components mix ratios vs use
specification controls Teardrop Park
horticultural strategy specifications
PineSwallow ENVIRONMENTAL
Robert Pine, PE, MLA, ASLA
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Soil Design Strategies Natural vs Blended
Blended Soils
Natural
Loam Dealer
Limited Resource
Controlled performance, Sustainable
Mix of whatever came in that day
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Specifying Soils for Complex Landscapes
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Soil Design Strategies Natural vs Blended

• Simple vs Complex Landscapes

Tanglewood
Teardrop Park
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Components
Base Loam

• Sand

Compost
Blended Soil
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Components
Natural Topsoil
Provides silt and clay particles
stable organics cation exchange capacity
natural soil biology
As percentage in a blend increases nutrient
and water holding capacities ? infiltration
rate and aeration ? resistance to compaction
? Note Good quality topsoil is required for
appropriate gradation, organics and soil
biology.
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Components
Uniform Coarse Sand
Provides structure macropore space
As percentage in a blend increases aeration
? infiltration rate ? resistance to
compaction ? water holding capacity ?
nutrient holding capacity ? Note Well graded
sand reduces aeration, infiltration and
resistance to compaction!
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Components
Mature Compost
Provides organic content micro-organisms
As percentage in a blend increases water
holding capacity ? soil biology ?
resistance to compaction ? resistance to
anaerobic conditions ? Note Immature compost
creates bad soil biology and increased
vulnerability to anaerobic conditions.
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Specification Controls
Primary Mix Design Specifications
Purpose define the soil blend control
soil properties
Estimated Mix Ratio for each soil Grain Size
Distribution Coefficient of Uniformity
Organic Content Horticultural Requirements
(CEC, pH, nutrients, etc.) Compaction Range
Saturated Hydraulic Conductivity at maximum
compaction
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Specifying Soils for Complex Landscapes
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Specifying Blended Soils Specification Controls
Primary Process Specifications
Purpose
Testing and confirmation of base
materials sand, loam, compost Testing to
confirm mix ratios Batch production and
testing prior to delivery for quality control
Handling and Placement procedures Control of
wet soils

• Ensure quality control
• Protect soil quality

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Specifying Soils for Complex Landscapes
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Teardrop Park Horticultural Strategy
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
High Use Turf
Soil Requirements Withstand heavy use
High infiltration rate
Specifications Mix Ratio 3S 1.5L 1C
passing 270 sieve 11 -14 Uniformity ratio
D70/D20 lt 4.5 Organic content 4 -
5 Compaction 86 - 88 Hydraulic
conductivity gt 4 inches/hr S Sand L
Base Loam C Compost
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Passive Use Lawn (not used at Teardrop Park)
Specifications Mix Ratio 2S 1.5L 1C
passing 270 sieve 15 - 18 Uniformity ratio
D70/D20 lt 5.0 Organic content 4 -
6 Compaction 84 - 86 Hydraulic
conductivity gt 3 inches/hr S Sand L
Base Loam C Compost
Soil Requirements Withstand moderate use
Moderate infiltration rate Reduced water
requirements
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Horticultural Subsoil
Soil Requirements rooting zone for trees /
shrubs free draining not vulnerable to
anaerobics
Specifications Mix Ratio 2S 1L passing
270 sieve 14 - 18 Uniformity ratio D70/D20 lt
6.0 Organic content 2 - 3 Compaction 82 -
85 Hydraulic conductivity gt 2 inches/hr S
Sand L Base Loam C Compost
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Trees with understory no ground cover
Specifications Mix Ratio 2S 1L 3C
passing 270 sieve 11 - 16 Uniformity ratio
D70/D20 lt 6.0 Organic content 9 -
11 Compaction 84 - 86 Hydraulic
conductivity gt 3 inches/hr S Sand L
Base Loam C Compost
Soil Requirements recreate natural forest
soil profile encouraging shallow feeder
roots deep rooting in horticultural subsoil
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Trees with understory with ground cover
Soil Requirements recreate natural forest
soil profile suitable for ground cover plants
Specifications Mix Ratio 2S 1L 2C
passing 270 sieve 11 - 16 Uniformity ratio
D70/D20 lt 6.0 Organic content 6 -
9 Compaction 86 - 88 Hydraulic
conductivity gt 3 inches/hr S Sand L
Base Loam C Compost
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Marsh Planting Soil
Specifications Mix Ratio 1S 2C passing
270 sieve 8 - 12 Uniformity ratio D70/D20 lt
4.5 Organic content 10 - 12 Compaction 82 -
85 Hydraulic conductivity gt 4 inches/hr Note
Medium Sand not Coarse S Sand L Base
Loam C Compost
Soil Requirements saturated conditions
support wetland plantings high water holding
capacity
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Boulder Base Mix
Soil Requirements structural support for
heavy boulders horticultural support for
plantings
Specifications Mix Ratio 1 part 1.5 to 2 inch
crushed stone 1 part tree soil mix Placed
beneath heavy boulders and compacted
thoroughly
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Steep slopes
Soil Requirements provide long term
stability protection from erosion tree
horticultural support
Specifications Mix Ratio 2 to 4 oz fibers per
cubic foot thoroughly mixed with planting
soil Placed and compacted to normal compaction
range for specified planting medium
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Specifying Soils for Complex Landscapes
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Teardrop Park Specifications
Trees in paved areas
Soil Requirements provide tree rooting
volume provide support for pavement
prevent settlements
Specifications Mix Ratio 4S 1L 1C
passing 270 sieve 7 - 9 Uniformity ratio
D70/D20 lt 3 Organic content 2 -
3 Compaction 92 - 94 Hydraulic
conductivity gt 6 inches/hr S Sand L
Base Loam C Compost
PineSwallow
Specifying Soils for Complex Landscapes
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Specifying Soils for Complex Landscapesrecap
Soil Design Strategies Natural vs Blended
Simple vs Complex Specifying Blended Soils
components mix ratios vs use
specification controls Teardrop Park
horticultural strategy specifications
PineSwallow ENVIRONMENTAL
Robert Pine, PE, ASLA