NATIONAL SOIL SURVEY CENTER LINCOLN, NE USDA-NRCS THE SCIENCE OF SOIL SURVEY INTERPRETATIONS

Introductions and Objectives  Name  Location  Years of service  Previous locations  Your objectives in this course  Your impressions on the Kellogg article

Week at a Glance  Day 1 – Theory and Background  Day 2 – Develop Narrative and a “Criteria Table”  Day 3 – Continue Narrative and the “Criteria Table”  Day 4 – Present and Defend Your Decisions

NEDC Objectives  Define a soil interpretation and explain its application  Understand that soil, landscape, and site characteristics impact land use  Understand that developing interpretations requires interdisciplinary expertise  Describe the steps for developing interpretations listed in NSSH Part  Develop a criteria table for an interpretation

Class Objective:  Develop an interpretation from a request for help  Use reasonable scientific criteria  This class does not require the use of NASIS, but you will need Google Scholar, Digitop, NAL, SSSAJ, etc …  You will work in small groups to decide how soil properties might impact the land use proposed

Define Interpretation: To explain or tell the meaning of, to present in understandable terms To explain or tell the meaning of, to present in understandable terms

Why do we interpret soils?  “Few people besides soil scientists know enough about soils, and about the interactions among the many soil characteristics that define each kind of soil, to do the job by themselves.”  “Experience shows that the soil scientist must take leadership in developing the interpretations.”  “The soil scientist must have help and guidance from competent people in the related fields.”  “Finally, his/her results should be tested in practical application. In fact, the soil scientist always lives in an atmosphere of criticism.”  Charles Kellogg

Core Mission of the Soil Survey Program > make an inventory of the soil resources of the United States; > keep the soil survey relevant to ever-changing needs; > interpret the information and make it available in a useful form; and > promote the soil survey and provide technical assistance in its use for a wide range of community planning and resource development issues related to non-farm and farm uses.

Define a “soil quality”  Behavior and performance attributes of soils that are not directly measured.  They are inferred from soil properties and dynamic (temporal or changeable) conditions.  Attributes such as corrosivity, tilth, natural drainage, frost action, and wind erodibility are qualities of soil.  Seems like another flavor of interpretation.

Define a “soil property”  Attributes of soils or sites that are or can be directly measured  They may be dynamic (temporal or changeable) conditions.  Attributes such as reaction, cation exchange capacity, content of clay, shape of the landform, parent material and so on

Pedotransfer Functions  Using data you have to approximate data that you want.

Interpretations NSSH 617  (a) Purpose  Soil survey interpretations predict soil behavior for specified soil uses and under specified soil management practices. They help to implement laws, programs, and regulations at local, state, and national levels. They assist the planning of broad categories of land use, such as cropland, rangeland, pastureland, forestland, or urban development. Soil survey interpretations also help to plan specific management practices that are applied to soils, such as irrigation of cropland or equipment use.

Basis of Soil Interpretations  Site features, such as slope gradient and mean annual air temperature  Whole soil properties, such as depth to a restrictive layer or depth to seasonal high water  Individual horizon features, such as clay content, pH, or content of rock fragments

Properties ?? What properties do you extract from a pedon description?? Pedon Description Properties Interpretations Lab Data

Examples  Interpretations ??  Properties ?? Texture ? Sand, silt and clay K factor ? Silt, VF Sand, Sand > 0.1mm, OM, Structure, Ksat Septic tank Adsorption fields? Ksat S, Si, C water table rocks flooding, etc

The Most Used Soil Properties: Estimate or measure these for every component  Sand %  Silt %  Clay %  Horizon Rock Fragment %  Water Relations (ksat, awc, water table, flood, pond)  Organic Matter %  Bulk Density

Interpretation Style  Limitation – 1.0 = Limited  Suitability – 1.0 = Suited  How do you decide which?  Hint – Customer comes first

Writing Soil Interpretation Criteria (617.09)  Step 1. Define the Activity  Step 2. Separate Aspects  Step 3. Identify Site Features  Step 4. List Soil Properties  Step 5. Select the Number of Separations  Step 6. Document Assumptions  Step 7. Develop the Criteria Table  Step 8. Application, Presentation, and Testing

Step 1. Define the Activity  describe the activity or use;  identify the purpose or purposes of the activity or use;  define the desired performance of the activity or use;  specify the soil depths that are affected;  identify the type of equipment for installation;  mention resource conditions that indicate a different activity or use or the misuse of this practice;  define the needed specific geographic detail, including the length and width and the direction of application if important; and  define the needed map and interpretation reliability and uniformity.

Defining the Activity  The more specifically defined the activity, the more it is interpretable  For example: “make an interpretation for wine grapes” versus “make an interpretation for Cabernet Sauvignon”  Sometimes the user may not know what they want and you need to work with them

Define the Activity Example  A person wants to buy some ground to grow wine grapes –What variety of grape? – Cabernet –Desired performance -- Is world class wines –Soil Depths --These vines require a deep soil, as old vines want to “root in Hell” –Type of equipment --The planting and pruning will be done by hand, but mowing and harvesting will require some tractors –Resource Conditions – Erosion concerns

Step 2. Separate Aspects  Separate different aspects of the activity for separate interpretations. Aspects of interpretations are planning elements that require different criteria, such as installation, performance, maintenance, and effect. Proceed through the steps to develop criteria for each aspect. Each aspect is a unique interpretation that has separate criteria and users. Mention other aspects that may need interpretation but are not addressed.

Separate Aspects  We do not normally explicitly separate the aspects, but we could  Usually, the soil/site property and aspect combination that is most limiting is reported

Separating the Aspects Example Aspect:  Planting (30 year life cycle)  Maintenance, for example mowing and pruning  Irrigation (as and if needed)  Harvest Criteria:  Some small equipment needed  See irrigation interpretation  Some equipment needed

Step 3. Identify Site Features  Identify significant site features for the interpretation and any assumptions about them. Site features are not soil properties, but are features such as climate factors, landscape stability hazard, vegetation, and surface characteristics. Identify and record the implied affect of site features on each aspect of the interpretation. Although site features are not soil properties, they are commonly recorded in soil databases and are valuable for developing interpretations because they are geographically specific to soils.

Examples of Site Features  Mean annual air temperature  Frost free days  Mean annual precipitation  Growing Degree Days  Surface stones  Land surface shape  Hillslope position  Parent material  Slope  Ponding  Flooding

Site Features, Cabernet Example Feature:  Slope gradient  Frost Free Days  Growing Degree Days  Slope Position  Slope Aspect Impacts:  Erosion, safety  Time required for maturation  Heat required for maturation  Air drainage, frost avoidance  Warming and growing season

Step 4. List Soil Properties  Identify and list the specific soil properties that are significant to the interpretation. Use only basic properties, qualities, or observed properties and do not make interpretations from previous interpretations or models.

Soil Features, Cabernet Example Feature:  pH  AWC  Restriction depth  Depth to water table  EC  Content of rock fragments Impacts:  Micronutrients, aluminum toxicity  Water required for plant growth  Rooting volume  Fungus growth, plant health  Water relations, micronutrients  Difficult planting, thermal mulch

Step 5. Select the Number of Separations  Select the number of interpretative separations (groups), and define the intent of the separation or classification. Each separation should have a purpose, which normally represents a significant management grouping and a need for separate treatment. Commonly used terms in separations are slight, moderate, and severe or good, fair, and poor. User needs dictate the number of separations. The levels of user needs may vary. Some users do not use groupings.

Separations Example

Step 6. Document Assumptions  Document assumptions about the significance of the property and established values for separating criteria. (a) A record of the significance of the property (b) Indicate why the feature is important and why the specific break was chosen (c) Establish values that are significant to the interpretation of the soil and not to the mapping of the soil

Literature List (Partial)  Wolf, T. K and Boyer, J. D Vineyard site selection. Publication  Gillerman, V. S., Wilkins, D., Shellie, K., Bitner, R Geology and wine 11. Terroir of the Western Snake River plain, Idaho, USA. Geoscience Canada 33:  Lasko, A. N., Kwasnowski, K., Krause, N., Ashmall, B. Vineyard Site Suitability Analysis. Cornell University.  Rutgers, The State University of New Jersey NJ Wine Grape Quick Facts.  Ohio State University. Midwest Grape Production Guide. Bulletin  Santos, J. A., Halheiro, J. C., Pinto, J. G., Jones, G Macroclimat and viticultural zoning in Europe: observed trends and atmospheric forcing. Climate Research 51:  …

Step 7. Develop the Criteria Table  Assign feature and impact terms, and develop the criteria table. The following categories of column headings are recommended for use in the criteria table: –Factor (this is the soil or site property); –Degree of Limitation (such as Slight, Moderate, Severe – Very Limited, Moderately Limited, Not Limited, etc.); –Feature (the term to be displayed for soil property); and –Impact (the dominant impact that the soil property has on the practice being rated).

Step 7. Develop the Criteria Table  Develop an Interpretive Statement: “A soil is limited for use as a medium for effluent renovation if it is too shallow, too steep, or too wet” “It is absolutely true that a soil is too wet for a septic system if the seasonal high water table is above 50cm”

Narrative for Criteria Table  Refer to Part 620 for a template  Define and describe the activity as narrowly as needed  Tell what the practice or activity is expected to accomplish  List and explain assumptions  List and explain site and soil property criteria  Provide a list of references and relevant literature

Example:  Terraces and diversions are embankments or a combination of an embankment and a channel constructed across a slope. They control erosion by diverting or storing surface runoff instead of permitting it to flow uninterrupted down the slope.  The soil properties and qualities that are used in rating soils for terraces and diversions are listed in Table  The soil properties and qualities that influence construction are slope, large stones, depth to bedrock or to a cemented pan, and wetness. Other properties and qualities that may cause problems after construction are restricted rooting depth, a high susceptibility to wind or water erosion, and restricted permeability to water and air. A high content of gypsum may cause piping or pitting.

A Criteria Table Septic Tank Absorption Fields Septic Tank Absorption Fields __LIMITS __LIMITS RESTRICTIVE PROPERTY SLIGHT MODERATE SEVERE FEATURE RESTRICTIVE PROPERTY SLIGHT MODERATE SEVERE FEATURE 1.USDA TEXTURE ICE PERMAFROST 2.FLOODINGNONERARE FREQ FLOODING OCCAS 3.DEPTH TO> <40 DEPTH TO ROCK BEDROCK (IN) 4.DEPTH TO HIGH> <4 WETNESS WATER TABLE (FT) 5.DEPTH TO > <40 CEMENTED PAN CEMENTED PAN (IN) (IN)

Cabernet-Sauvignon Criteria PropertySlight Limitation Somewhat Limited Severely Limited Restrictive Feature

Step 8. Application, Presentation, and Testing  (a) Database needs  (b) Temporal considerations for application  (c) Reliability  (d) Testing  (e) Date the interpretation and criteria

In-class Interpretation Projects  Land Smoothing, Code 466  Tree/Shrub Site Preparation, Code 490  Thermal conductivity of soils  Soil/site suitability for white oak  Submissions from the group

Sideboards  No NASIS is needed, but knowledge of the data in the database would be good  Google, Wiki, National Ag Library, DigiTop  Do not limit yourselves in terms of kinds of soil properties  If an attribute is currently lacking, perhaps it can be approximated using a pedotransfer function

Sideboards  Think about “capacity” factors versus “intensity” factors, what is really driving the system, for example, pH and CaCO3 content  Think about the relationships between soil properties, covariance and dependence, for example CEC and LEP

Sideboards  Consider using continuous variables as much as possible, for example, “content of clay” rather than “texture class”  Scope should be National  Report 6 or so properties  Avoid basing interpretations on other interpretations as much as is practical, for example, use “soil moisture” data rather than “drainage class”

Sideboards  Contradictory information from geographically different areas suggests an interaction between the soil/site properties and their impact on land use

Mechanics of Communicator  Meeting with remote people or people that are remote  Can be written or spoken

For the Rest of Today and Tomorrow:  Step 1. Define the Activity  Step 2. Separate Aspects  Step 3. Identify Site Features  Step 4. List Soil Properties  Step 5. Select the Number of Separations  Step 6. Document Assumptions  Step 7. Develop the Criteria Table

A Simple Criteria Table