in the Maryland Soils Database” “Updates of K factor, T factor, and Hydrologic Soil Groups in the Maryland Soils Database” Webinar Thursday Feb. 23, 2012 1:00 -2:00 PM This is basically what I want to talk about today. I tend to talk a little fast so if I’m flying by one let Amanda know and I’ll slow it down. That was the Tor that came across Southern Maryland a couple of years ago. Presented by James Brewer Resource Soil Scientist - Easton, MD

ANY QUESTIONS!! Don’t hesitate to ask!

WEBINAR OBJECTIVES NASIS – Stored vs Calculated What, Where, Why K Factors T Factor HSG’s Sidebar Discussion RUSLE2 HEL Clarification NASIS – national soils database and what interpretations to be calculated (this were previously stored and manual determined) National endeavor working towards a seamless digital soil survey across the United States. Talk about definitions, where these interpretations are used, and why we’re calculating them. Sidebar discussions throw in here and there

SOILS DATABASE Been around since early 90’s; MD late 90’s. Have had a couple of versions. Extremely powerful program.

SOIL PROPERTY DATA ELEMENTS Over 150 individual entries populated Many have Low, RV, and High Just an example.

SOIL PROPERTY DATA ELEMENTS List of some properties: Available Water Capacity Bulk Density Cation-Exchange Capacity Electrical Conductivity Flooding Frequency, Duration Rock Fragments Horizon Depth Slope Liquid Limit Organic Matter Particle Size Percent Passing Sieves Ponding Depth, Duration , Frequency Reaction, Soil (pH). Saturated Hydraulic Conductivity You might be familiar with these. All are in various tables and reports in WSS, SDV, and SDM. All of these would have low, RV, and high values.

SOIL PROPERTY DATA ELEMENTS Used to generate: “Soil Property Interpretations” Corrosion Drainage Class Engineering Classification Excavation Difficulty Classes Potential Frost Action Hydrologic Soil Groups Soil Erodibility Factors Soil Slippage Potential T Factor Wind Erodibility Group and Index I like to call them “SPI”. Underlined will be calculated. Basically using those soil properties to generate interpretations.

NASIS – Stored vs Calculated Interpretations K Factor – Soil Erodibility T Factor – Soil Loss Tolerance HSG - Hydrology Soil Groups WEG – Wind Erodiblity Group WEI – Wind Erodibiltiy Index Steel Corrosion Concrete Corrosion. Orange are what we’re going to talk about today.

NASIS Calculations – Based On? Better soil property data for most, if not all individual components. Both major and minor. (K factors, Corrosion Potentials) Change in criteria used to generate soil property interpretations (T factors, HSG, WEG, WEI) Two main reasons why these SPI are being calculated and why the results could be different then before.

WHY CALCULATE???? Need to populate commonly used values (property interpretations) Can’t measure directly but can be consistently derived from other date Over entire database

WHY CALCULATE???? Increase internal consistency in the database Within map units, components, horizons In other words: The same “stuff” will have the same “values”

SPLASH EROSION One of the pretty neat pictures related to K factor and erosivity. Another reason for cover crops. Keeping soil surface covered is important, “at all times”. RAINDROPS FALLING ON EXPOSED SOIL CAN BREAK OFF SOIL PARTICLES TO BE LOST IN RUNOFF WATER

What is K factor?? Measure of soil erodibility under standard unit plot condition 72.6 ft long, 9% steep, tilled continuous fallow, up and down hill tillage Major factors affecting it Particle sizes, organic matter, structure, permeability and yes rock fragments A key point is that soil erodibility is determined under the standard reference condition where management effects have been eliminated by maintaining the unit plots in a continuous tilled, fallow conditions for a number of years.

SOIL ERODIBILITY - K General effect of texture Fine textures: (clays) resistant to detachment because of aggregation Coarse textures: (sands) easily detached, but low runoff, large, dense particles not easily transported Medium textures: (loams) moderately detachable, moderate to high runoff Silts: easily detached, high runoff, small, easily transported sediment

Two Kinds of K Factors Kf applies only to the fine-earth (less than 2.0 mm) fraction [Kf – free of rock fragments] Kw factor applies to the whole soil, includes rock fragments within the soil layer [Kw – with rock fragments] Hence the letter f and w.

Kf - Based on Wischmeier Nomograph Pronounced wish meyer. Developed in late 1960’s. From soil properties. Show how with highlighter. Has a mathematical equation that runs the NASIS calculation.

Kf and Kw Factor Classes Tons per acre per U.S. erosivity unit 0.02 0.05 0.10 0.15 0.17 0.20 0.24 0.28 0.32 0.37 0.43 0.49 0.55 0.64 Standard classes used. To be calculated for each component horizon or layer, major and minor. Lower number less erosive. Higher number more erosive.

Kf and Kw Factor Classes Generalizations Fine textures: (clays) 0.05-0.15 Coarse textures: (sands) 0.05-0.20 Medium textures: (loams) 0.25-0.45 Silts: 0.45-0.65 Values shown are typical K factors for those texture groups.

Kf value classes of less than 2 mm soil fraction Convert Kf to Kw Fragment vol. % Mulch factor 1/ Kf value classes of less than 2 mm soil fraction .10 .15 .20 .24 .28 .32 .37 .43 .49 .55 .64 5 .90 .09 .14 .18 .22 .25 .29 .33 .39 .44 .50 .58 10 .77 .08 .12 .38 .42 15 .68 .07 .16 .19 20 .61 .06 .17 .23 .26 .30 25 .54 .05 .11 .13 .35 30 .48 .21 .31 35 .04 18 40 45 .34 .03 50 55 60 .02 65 70 75 .01 80 85 90 95 100 Table for conversion RF and Mulch. Kw always lower then Kf.

Where is K factor used? Maryland’s COMAR - Highly Erodible Soils (HES) NRCS RUSLE2 NRCS – Highly Erodible Land (HEL) MDA – Phosphorus Site Index

COMAR Highly Erodible Soils Found in: FOREST CONSERVATION - 08.19.03.00. AGRICULTURAL LAND PRESERVATION - 15.15.07.00. Stormwater Management Plans - 26.17.02.00. NONTIDAL WETLANDS -26.23.01.00. CRITICAL AREA - 27.01.01.00. 2011 MD Stand. And Specs. Soil Erosion and Sediment Control– Design and Construction Manual Regulations

COMAR HES Soils with a slope >15 % or Soils with a K value >0.35 and with slopes >5 % Kf or Kw, not sure?? Some Forest regs use just slopes, some use >25% slopes Critical Area stated USLE Stand and Spec for Soil Ero and Sed Control stated use Kw This is why f and w should always be used with K.

PICTURES SPEAK LOUDER THAN WORDS Throw in a couple of pictures. Water and wind LOUDER THAN WORDS

NRCS RUSLE2 RUSLE2 uses the Kf (fine-earth, rock free) factor Surface layer Kf from NASIS database via Soil Data Mart via Purdue Univ. Just a brief review of RUSLE2 as related to K factor.

NRCS RUSLE2 Select County and Map Unit Component Kf loaded into equation in “background” Can’t be changed? MD RUSLE2 Guide book states it can be changed. If you don’t have a soil with K, which 99% of ours do.

From MD RUSLE2 User's Guide 06/2008 The soil object includes information on soil erodibility, soil texture, hydrologic soil group, and rock cover. Also, this object includes the soil erodibility to compute a value for the soil erodibility factor if one is not available. Maybe??

Adjusting Rock Cover in RUSLE2 Why RUSLE2 uses Kf.

Guidelines for Rock Cover in RUSLE2 Rock cover on the soil surface affect the Cover & Management factor in RUSLE2 Rock cover (fragments) does not affect the Soil Erodibility factor used in RUSLE2 RUSLE2 uses the Kf (rock free) soil erodibility factor.

Guidelines for Rock Cover in RUSLE2 Using Kw would would “double account” of the effect of cropping & management Don’t use rock cover or rock content values from soil survey data Measure in field like you do plant litter If present and not entered in RUSLE2, erosion is over predicted NASIS database has a element entry for surface rock fragments but hasn’t been populated in all components. Plus data not available outside NASIS. OM similar to rock cover. Inherit OM is in Kf nomograph. OM on surface is a cover & management factor.

Guidelines for Rock Cover in RUSLE2 Or use table from MD RUSLE2 User's Guide 06/2008 Surface texture modifier found in component name. RUSLE2 Rock Fragments Defined as > 3/8 in size

Where to find Kf? Web Soil Survey, Soil Data Viewer, Soil Data Mart, or eFOTG

General trends for results of K Calculations in Maryland Lower Eastern Shore Soils K for ~35% components will increase by 1 or more classes   K for ~25% components will decrease by 1 or more classes This may not have a lot of impact, as there is not much farm land with >5% slope This data based on Major components only. Doing draft calculations:

General trends for results of K Calculations in Maryland Western Coastal Plain and Upper Eastern Shore Soils   K for ~ 20% components will increase by 1 or more classes ~ 39% are C and D slope map units K for ~ 48% components will decrease by 1 or classes ~ 37% are C and D slope map units This data based on Major components only.

General trends for results of K Calculations in Maryland Piedmont Soils K for ~ 35% components will increase by 1 or more classes ~ 46% are in C and D slope map units   K for ~ 22% components will decrease by 1 or more classes ~ 37% are in C and D slope map units This data based on Major components only. B slopes could be important also since they range up to 8%.

General trends for results of K Calculations in Maryland Mountain Soils K for ~ 28% components will increase by 1 or more classes ~ 46% are in C and D slope map units   K for ~ 45% components will decrease by 1 or more classes ~ 25% are in C and D slope map units This data based on Major components only. B slopes could be important also since they range up to 8%. Looks like pretty much across the state will be evenly affected by the calculation of K. Both increase and decrease of the K classes.

Half Way Through Questions so far?

Factors of Soil Formation: s = f' ( cl, o, r, p, t ) One of the most important things to understand about soils.

Three Areas of Importance HEL DETERMINATIONS Three Areas of Importance When to use Frozen 1990 HEL Map unit list Field visit for PHEL areas or where SS updated since 1990 CRP – Different HEL Determinations This can be confusing. I had to read it several times in NFSAM Sec. 511. We don’t do it very often anymore, I think.

HEL Frozen Map Unit List - 1990 Used for HEL or NHEL PHEL - onsite required for determination to verify HEL or NHEL Most of these determinations should have been completed in the past.

Field Visit Includes PHEL Map Units Verify HEL or NHEL to finialize. (maybe due to field boundary changes) New determination can be issued for specific crop field. (using Jan. 1990 K and T factor data) May not have been done in past.

Soil Survey Updated Since Jan. 1990 Any new HEL map units can be appended to the Frozen List Crop fields with previous HELC determinations will not be changed by any additions of new map units to the list No map unit on Frozen List will have its HEL determination changed.

CRP – HEL Determinations (Automated System) Doesn’t use Frozen Map Unit List -1990 Doesn’t use specific soils mapping of original HEL Uses current soils data in Toolkit (SDM) Uses average of 3 major soils in acreage Procedure has changed several times since 1990. Uses average of 3 major soils in acreage, being offered into CRP. Cannot be compared to HELC/WC (AD 1026) compliance determination. Two different technologies and procedures.

Maryland COMAR HES Highly Erodible Soils NRCS/FSA HEL DETERMINATIONS Highly Erodible Land HEL Frozen Map Unit List - 1990 Maryland COMAR HES Highly Erodible Soils Soils with a slope >15 % or Soils with a K value >0.35 and with slopes >5 % Just to review of the two. Different! Highly Erodible Land vs Highly Erodible Soils.

NOT TIME TO RELAX YET! Questions?

What is T Factor?? Soil Loss Tolerance Definition - maximum amount of erosion at which the quality of a soil as a medium for plant growth can be maintained Classes - 1, 2, 3, 4, and 5 T factors - represent the goal for maximum annual soil loss Tons per acre. Measured by USLE and RUSLE2. Obviously class 5 (tons allowable loss) is better than 1 (ton allowable loss) To be calculated for each map unit component, major and minor.

T Factor - Soil Loss Tolerance Calculated from the soil properties and qualities. Criteria from: 1. The severity of physical or chemical properties of subsurface layers; and 2. The economic feasibility of utilizing management practices to overcome limiting layers or conditions. Based on soil not frozen. Based on soil surface bare. Slope is not considered.

T Factor - Soil Loss Tolerance 19 Soil Characteristic in Criteria: Organic Bedrock Fragmental Rock fragments Fragipan Sandy substratum High aluminum Important ones in MD and DE.

Maryland Soil Property Changes T Factor Calculations Maryland Soil Property Changes Piedmont/Mountain Soils Bedrock Fragipan Rock fragments Coastal Plain Soils Sandy substratum High aluminum (may over ride) Remember I said there was a change in criteria of the soil properties used to generate the T factor interpretations. Bedrock & Fragipan: revised to include more taxonomic classification criteria Rock fragments: removed size criteria Sandy substratum: removed regional geo-political guides (MLRA’s) in criteria; added more specific Ksat data Al saturation: brand new soil property criteria considered Other reasons: some errors in database; some “null values” in database where data is required;

Where is T factor used? NRCS RUSLE2 NRCS – Highly Erodible Land (HEL) NRCS – Many Conservation Programs State Land Planning Programs Commonly serves as goals for conservation planning on farms. Assist in the identification of cropping sequences and BMP’s that maximize production and sustain it.

General trends for results of T Calculations in Maryland Lower Eastern Shore Soils T for ~4% map unit acreage will increase by 1 or more classes   T for ~20% map unit acreage will decrease by 1or more classes Based on Major components

General trends for results of T Calculations in Maryland Western Coastal Plain and Upper Eastern Shore Soils T for ~17% map unit acreage will increase by 1 or more classes   T for ~35% map unit acreage will decrease by 1or more classes Based on Major components

General trends for results of T Calculations in Maryland Piedmont Soils T for ~8% map unit acreage will increase by 1 or more classes   T for ~10% map unit acreage will decrease by 1or more classes Based on Major components s

General trends for results of T Calculations in Maryland Mountain Soils T for ~5% map unit acreage will increase by 1 or more classes   T for ~12% map unit acreage will decrease by 1or more classes Based on Major components So T calculations will affect the Coastal Plain Soils of Maryland the most.

I’m spreading it pretty thick now. Questions?

What are Hydrology Soil Groups?? Definition - group of soils having similar runoff potential under similar storm and cover conditions Official - National Engineering Handbook, Chapter 7 Classes - A, B, C, and D, and three dual classes, A/D, B/D, and C/D Just like a soils drainage classes, Class D may be better then Class A or vise verse depending upon the intended use. To be calculated for each map unit component, major and minor.

Hydrology Soil Groups Criteria - uses soil properties that influence runoff potential Soil Properties: Depth to a seasonal high water table Saturated hydraulic conductivity (Ksat) after prolonged wetting Depth to a layer with a very slow water transmission rate. Changes in soil properties caused by land management or climate changes also cause the hydrologic soil group to change. Like T factors, there was a change in criteria of the soil properties used to generate the HSG interpretations.

General HSG Descriptions Based on all when thoroughly wet Group A Soils - low runoff potential Group B Soils - moderately low runoff potential Group C – Soils moderately high runoff potential Group D – Soils high runoff potential or high water table

General HSG Descriptions Based on all when thoroughly wet Duel Groups – used when D group soils can be adequately drained Assigned to dual hydrologic soil groups (A/D, B/D, and C/D) based on their saturated hydraulic conductivity and the water table depth when drained. The first letter applies to the drained condition and the second to the undrained condition. Example: Poorly drained Elkton c/d Poorly drained Hatboro b/d

Maryland Soil Property Changes HSG’s Calculations Maryland Soil Property Changes Pre Calculations: Assignment to group by general criteria guidelines Example A group: high infiltration rate; deep; well drained to excessively drained sands or gravels Example C group: slow infiltration rate; moderately fine to fine texture

HSG’s Calculations Maryland Soil Property Changes Present Calculations: Assignment to group by detailed calculation of very specific criteria Example A group: Very specific depths and Ksat (permeability) rates.

HSG’s Calculations Maryland Soil Property Changes Present Calculations: Example A group: Every group has three assignment criteria depending upon depth of impermeable layer and or depth to WT.

HSG’s Calculations Maryland Soil Property Changes Present Calculations for Duel Classes: Example A/D group: WT break is on 24” Our Drainage class breaks at 20” Now SWPD have duel classes Plus our map units with poorly and very poorly drained soils have two major components with drained and undrained phases and they both get assigned duel classes, should be D for undrained and other for drained. Along with permanently high water table soil.

Hydrology Soil Groups Where used? HSG’s used in equations that estimate runoff from rainfall. Solving hydrologic problems in planning watershed protection Flood prevention projects Planning & designing structures for the use, control, and disposal of water.

Hydrology Soil Groups Where used? Many Federal, State, and Local Engineering Land Use Management programs and practices and BMP’s RUSLE2 for use in Subsurface Drainage Systems NRCS Waste Management Soil Interpretations MDE - SWM and SEC Practices

General trends for results of HSG Calculations in Maryland Coastal Plain Soils B to other class – 38% of components Piedmont and Mountain Soils D to Duel – 11% of components C to D – 10% of components C to B – 9% of components B to A - 8% of components Big thing on Coastal Plain, the B’s went to A’s.

Questions? james.brewer@md.usda.gov 410 822 1577 x 121