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