ASLA’s New Landscape Soil ASLA’s New Landscape Soil Specification SystemSpecification System

ASLA Professional Practice ASLA Professional Practice CommitteeCommittee

By By Barrett L. Kays, Ph.D., FASLABarrett L. Kays, Ph.D., FASLA

www.barrettkays.comwww.barrettkays.com

ASLA Professional Practice ASLA Professional Practice CommitteeCommittee

ASLA PPC is developing two new ASLA PPC is developing two new publications entitled: publications entitled: ““Soils Analysis and Design for Landscape Soils Analysis and Design for Landscape

Plantings”Plantings” ““Soils Design Testing and Specifications Soils Design Testing and Specifications

for Landscape Plantings”for Landscape Plantings”

Publication ChaptersPublication Chapters

““Soils Analysis and Design for Soils Analysis and Design for Landscape Plantings” Landscape Plantings” Selecting the Type of Landscape/Soil Selecting the Type of Landscape/Soil

SettingSettingSelecting the Type of Landscape PlantingsSelecting the Type of Landscape PlantingsSolving Soil Landscape Design IssuesSolving Soil Landscape Design Issues

Publication ChaptersPublication Chapters

““Soils Design Testing and Speci-Soils Design Testing and Speci-fications for Landscape Plantings”fications for Landscape Plantings”Selecting the Types of Landscape SoilSelecting the Types of Landscape SoilDetermining the Types of Design Soil Determining the Types of Design Soil

TestingTestingDetermining the Types of Construct-ion Determining the Types of Construct-ion

Soil TestingSoil TestingPreparing the Soil SpecificationsPreparing the Soil Specifications

Structural Soils at the Great Structural Soils at the Great Lawn in Central ParkLawn in Central Park

Types of Custom Soil Solutions Types of Custom Soil Solutions

Amended on-site topsoilsAmended on-site topsoils Amended on-site subsoilsAmended on-site subsoils Imported native mineral soilsImported native mineral soils Imported native organic soilsImported native organic soils Manufactured structural soilsManufactured structural soils Manufactured light weight soilsManufactured light weight soils Manufactured moisture retentive soilsManufactured moisture retentive soils Manufactured layered soilsManufactured layered soils

Landscape/Soil SettingLandscape/Soil Setting

Determining soil characteristics from your county Determining soil characteristics from your county soil surveysoil survey– Soil textureSoil texture– Soil depthSoil depth– Drainage classesDrainage classes – Soil structureSoil structure– Soil densitySoil density– PermeabilityPermeability– Hydrologic groupsHydrologic groups– Hydraulic conductivityHydraulic conductivity– Available water capacityAvailable water capacity – Depth to seasonally high water tableDepth to seasonally high water table – Shrink-swell potentialShrink-swell potential– Soil disturbanceSoil disturbance

Soil Drainage ClassesSoil Drainage Classes

Select plants by the drainage class of the soils on your Select plants by the drainage class of the soils on your sitesite– Very poorly drained – water table within 12” and dark surface soil –

obligate & facultative wet plants– Poorly drained – water table within 12” – facultative wet &

facultative plants– Somewhat poorly drained – water table 12 to 24” –facultative plants– Moderately well drained – water table 24 to 48” – facultative upland

plants– Well drained – water table 48 to 72” – upland plants– Somewhat excessively well drained – water table 72 to 96” –

drought resistant plants– Excessively well drained – water table greater than 96” – drought

resistant plants

Depth to Seasonal Water TableDepth to Seasonal Water Table

• Gray soil colors are due to high water table and leaching of iron

• Soil horizons that are dominate gray are due to water table in the horizon for extended periods of time during normal year

• Soil horizons that have gray mottles are due to seasonal water table in the horizon for at least 28 days during the wetter season – Iron oxides produces the reddish colors in soil– After the iron leaches, it leaves a gray color– The iron that leaches then moves downward in the soil and

then precipitates and forms red mottles just above the normal water table.

Munsell Soil Color for 10 Munsell Soil Color for 10 Yellowish Red HuesYellowish Red Hues

Seasonally High Water Table Using Seasonally High Water Table Using Gray Soil ColorsGray Soil Colors

Soil Water CalculatorSoil Water Calculator

Soil Water Characteristics Hydraulic Soil Water Characteristics Hydraulic Properties CalculatorProperties Calculator

http//hydrolab.arsusda.gov/soilwater/index.htmhttp//hydrolab.arsusda.gov/soilwater/index.htm

Amending Clayey Soils On-SiteAmending Clayey Soils On-Site

Installing Manufactured Structural Soil Material Installing Manufactured Structural Soil Material

Installing Manufactured Sandy Soil MaterialInstalling Manufactured Sandy Soil Material

Types of Soil TestingTypes of Soil Testing• Soil texture Analysis

– Sand, silt & clay percent– Sand graduation

• Soil physical analysis– Bulk density– Hydraulic conductivity – Infiltration rate – Moisture holding capacity

• Soil chemical analysis– Soil fertility analysis– Soil incubation fertility analysis

• Biological testing• Layered soil testing• Compost testing

Soil Core Sampling for Laboratory Soil Core Sampling for Laboratory Hydraulic Conductivity Testing Hydraulic Conductivity Testing

Incubation Soil Fertility TestingIncubation Soil Fertility Testing

• Mixing of limestone – Raises soil pH

• Mixing of sulfur – Lowers soil pH

• Mixing of gypsum – Improves soil structure in alkaline soils

• Mixing of phosphorus– Overcomes fixation in acidic soils

• Mixing of organic humus– Improves structure, moisture and nutrients

AppendicesAppendices• RFP for on-site soil survey• State and provincial soil testing laboratories in US

and Canada• Laboratory testing method references

– Physical testing– Chemical testing– Fertility testing– Fertility incubation testing– Biological soil testing– Layered soil testing– Compost testing

• Imported topsoil standards• Compost and peat-humus standards• List of commercial physical amendments• List of commercial fertilizers• List of organic fertilizers• Limestone standards

ASLA’s New Landscape Soil ASLA’s New Landscape Soil Specification SystemSpecification System

ASLA Professional Practice CommitteeASLA Professional Practice CommitteeBy By

Barrett L. Kays, Ph.D., FASLABarrett L. Kays, Ph.D., FASLAwww.barrettkays.comwww.barrettkays.com