Chemical and Physical Soil Conditions to Consider During

Tree Planting Operations

Fred C. Schoenagel III

Resource Soil Scientist

USDA-NRCS

Limitations of Soils

Web Soil Survey – Forestry Reports

Web Soil Survey – Forestry Reports

Soil and site features that may create limitations for use

Types of Water Tables

Chippewa Series Alden Series

(regional water table) (perched water table)

The “Chemistry” of Iron Transformation in Soils

Because iron is such a prevalent coloring agent in soils, it is a reliable indicator of the presence of anaerobic conditions due to saturation by water, based on the actual colors found within the soil profile

FeOOH + e- + 3H+ = Fe2+ + 2H2O

oxidized <<<<====>>>> reduced

(red or yellow soil colors) (gray or gley soil colors)

Water table as a limitation

Fragipans

restrict plant root penetration and downward water movement

Wurtsboro Series

Fragipans

• commonly have prismatic structure with visible prisms

• may also have platy structure or no structure at all (“massive”)

Idealized prisms

Perched Water Table

Fragipan as a limitation

Bedrock and Rock outcrops

Bedrock exposed at the ground surface is called “Rock outcrop”, and is mapped as a component of a map unit if it comprises a significant percentage of an area

Arnot Series

bedrock

rock outcrops

Bedrock/Rock outcrops as limitations

High Rock Fragment Content

Manlius Series Paulins Kill Series

High rock fragment content as a limitation

Surface stoniness as a limitation

Slope Aspect: The compass bearing (in degrees, corrected for declination) that a slope faces, viewed downslope; e.g., 287°. Can also be expressed as a compass direction; e.g., NE or southwest, etc. Slope Gradient: The angle of the ground surface (in percent) through the site and in the direction that overland water would flow (commonly referred to as slope); e.g., 18%. It is a measure of the change in elevation of the ground surface over distance.

Slope

Taken from: Schoeneberger, P.J., D.A. Wysocki, E.C. Benham, and Soil Survey Staff. 2012. Field book for describing and sampling soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

Slope Complexity:

Slope Shape:

Taken from: Schoeneberger, P.J., D.A. Wysocki, E.C. Benham, and Soil Survey Staff. 2012. Field book for describing and sampling soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.

Slope as a limitation

Chemical Properties

• reaction (pH)

• nutrient levels/availability

Soil properties that may create limitations for use

Sand: <2.0 – 0.05 mm Silt: 0.05 – 0.002 mm Clay: <0.002 mm

Reference: From the Surface Down, USDA-SCS, 1991

• basically “inert”; contributes to pore space

• can make soils droughty and infertile

• makes a soil feel gritty or rough

• basically “inert”; contributes to pore space

• can make soils easy to erode

• makes a soil feel soft or smooth

• the “active” part of soils; contributes to CEC

• can help soils hold on to nutrients and water

• makes a soil feel sticky when moist or wet and hard when dry

Soil texture (sand) as a limitation

Soil texture (silt) as a limitation

Soil texture (clay) as a limitation

The aggregation of soil particles into structural units called “aggregates” or “peds” Soil particles can be aggregated together by: • clay minerals • calcium ions • iron oxides • organic matter • organic compounds exuded by microorganisms

Soil Structure

Reference: Soils: An Introduction. Macmillan Publishing Co., 1987.

Soil Structure - Shapes

granular

prismatic

subangular (left) and angular blocky platy

Reference: Field Book for Describing and Sampling Soils, Version 3.0. Soil Survey Staff, 2012.

Granular soil structure contributes to significant pore space in the surface horizon of this soil.

Pore Space

Reference: Soils: An Introduction. Macmillan Publishing Co., 1987.

Reference: From the Surface Down, USDA-SCS, 1991

Live demo at: http://www.youtube.com/watch?v=vmo0FRAVgkM

Soil Reaction (pH)

Ultra Acid <3.5 Extremely Acid 3.5 to 4.4 Very Strongly Acid 4.5 to 5.0 Strongly Acid 5.1 to 5.5 Moderately Acid 5.6 to 6.0 Slightly Acid 6.1 to 6.5 Neutral 6.6 to 7.3 Slightly Alkaline 7.4 to 7.8 Moderately Alkaline 7.9 to 8.4 Strongly Alkaline 8.5 to 9.0 Very Strongly Alkaline >9.0

Nutrient Levels/Availability

Dependent upon/influenced by:

• soil series • past land use/management

Can be determined by:

• soil lab tests • in-field tests

Reference: Soil Interpretations for Intensive Forest Biomass Harvesting, Bliss, C.M., USDA-FS

Soil reaction (low pH) as a limitation

Delaware Series Washington Series