ASLA’s New Landscape Soil Specification System ASLA Professional Practice Committee By Barrett L. Kays, Ph.D., FASLA www.barrettkays.com

ASLA Professional Practice Committee ASLA PPC is developing two new publications entitled: “Soils Analysis and Design for Landscape Plantings” “Soils Design Testing and Specifications for Landscape Plantings”

Publication Chapters “Soils Analysis and Design for Landscape Plantings” Selecting the Type of Landscape/Soil Setting Selecting the Type of Landscape Plantings Solving Soil Landscape Design Issues

Publication Chapters “Soils Design Testing and Speci-fications for Landscape Plantings” Selecting the Types of Landscape Soil Determining the Types of Design Soil Testing Determining the Types of Construct-ion Soil Testing Preparing the Soil Specifications

Structural Soils at the Great Lawn in Central Park

Types of Custom Soil Solutions Amended on-site topsoils Amended on-site subsoils Imported native mineral soils Imported native organic soils Manufactured structural soils Manufactured light weight soils Manufactured moisture retentive soils Manufactured layered soils

Landscape/Soil Setting Determining soil characteristics from your county soil survey Soil texture Soil depth Drainage classes Soil structure Soil density Permeability Hydrologic groups Hydraulic conductivity Available water capacity Depth to seasonally high water table Shrink-swell potential Soil disturbance

Soil Drainage Classes Select plants by the drainage class of the soils on your site 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 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 Yellowish Red Hues

Seasonally High Water Table Using Gray Soil Colors

Soil Water Characteristics Hydraulic Properties Calculator Soil Water Calculator Soil Water Characteristics Hydraulic Properties Calculator http//hydrolab.arsusda.gov/soilwater/index.htm

Amending Clayey Soils On-Site

Installing Manufactured Structural Soil Material

Installing Manufactured Sandy Soil Material

Types of Soil Testing Soil texture Analysis Soil physical 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 Hydraulic Conductivity Testing

Incubation 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

Appendices 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 Specification System ASLA Professional Practice Committee By Barrett L. Kays, Ph.D., FASLA www.barrettkays.com