«David Hammonds, Environmental Manager Florida Department of Health Division of Disease Control and Health Protection Bureau of Environmental Health ...»
AND SOIL TEXTURES
ACT PRESENTATION 1 SEPTEMBER 2013
David Hammonds, Environmental Manager
Florida Department of Health
Division of Disease Control and Health Protection
Bureau of Environmental Health
Onsite Sewage Programs
• Materials for the soils training section were
provided by the FDOH, USDA Natural
Resources Conservation Service, Wade Hurt, Dr. Willie Harris, Dr. Mary Collins, Dr. Rex Ellis, the Florida Association of Environmental Soil Scientists, Dr. Michael Vepraskas, the University of Minnesota and the US EPA Design Manual.
• Properly identifying soil morphology (soil characteristics observable in the field, including horizonation) is the most important step leading to a properly permitted, functional onsite sewage treatment and disposal system. If you make mistakes at this step, the worst‐case scenario is that the system will not meet required health standards and put the public at risk of waterborne disease.
Properties used in describing soil layers Color: A key property in soil interpretation
• Most evident
• Influenced by Organic Matter (OM) and redox‐ sensitive metals such as Iron (Fe) and Manganese (Mn)
• REDOX=Oxidation/Reduction reaction‐ a process in which one or more substances are changed into others
• Wetness affects OM and redox‐sensitive metals
• Soil Color ‐ the dominant morphological feature used to predict the SHWT
• Matrix – dominant (background) color(s) of soil horizon (can be ≥1 color)
• Mottle – splotch of color, opposite of matrix
• Redoximorphic (Redox) Features – specific features formed from oxidation‐reduction reactions used to predict seasonal high water tables, includes certain types and amounts of mottles. They are caused by the presence of water and minerals in the soil.
Proper Coloring Methodology
• USDA NRCS notation, methodology, and terminology is referenced by DOH regulations and therefore MUST be used for ALL OSTDS purposes when describing soils (i.e. soil textures and colors)
• No other methodology is acceptable.
The Munsell Soil Color Charts
• Newest book came out in February 2013.
• Can use older books if consistent with current information (more later).
• 10YR AND 7.5YR replacement sheets currently available.
Munsell Color Notation
• Used to describe soil color for maximum accuracy and communication.
• Three descriptive elements are used and are always written in the following specific order.
HUE VALUE/CHROMAExample: 10R 5/8 HUE
• Identifies the basis spectral color or wavelength (Red, Yellow, Blue, or in‐ between, such as Yellow‐Red etc.)
• Normally one HUE on each page in the Munsell Soil Color Charts book ( are exceptions such as Gley colors‐more later)
• Most commonly used Hue in Florida is 10YR (but don’t just look on that page) HUE Symbols (letter abbreviations)
• R = Red; YR = Yellow‐Red; Y = Yellow
• The letter is preceded by numbers 0 to 10
• Within each letter range the Hue becomes more yellow and less red as the numbers
increase. For example:
– 2.5YR is more red than 5YR – 7.5YR is less yellow than 10YR
• Gley Charts include Neutral, Yellow, Green, Blue, Purple, and combinations.
• The middle of the letter range is at 5 and the 0 point is the same as the 10 point of the next redder Hue.
• Therefore, 5YR is in the middle of the yellow‐ red Hue, which extends from 10R (0YR) to 10YR (0Y).
• Pages in Munsell Book are prearranged from most red through most yellow.
Hue ‐ basis spectral color; wavelength RED SAME Moving from left to right becomes more HUES yellow, even within groups 0R 2.5R 5R 7.5R 10R YELLOW-RED SAME HUES 0YR 2.5YR 5YR 7.5YR 10YR YELLOW Hues in blue are the common soil hues. 0Y 2.5 Y 5Y 7.5Y 10Y Note increments of 2.5 between each consecutive hue (this is one unit of hue) VALUE
• Indicates the degree of lightness or darkness, or reflectance of an object viewed in daylight
• Scale is from 0 for the ideal black to 10 for the ideal white, in steps (units) that are visually equal.
• Lightness increases from black at the bottom of page, through the grays, to nearly white at the top of the page.
PURE WHITE 10/0
ValueThe Degree ofLightness or GRAY 5/0Darkness ofthe SpectralColor
PURE BLACK 0/0 CHROMA
• The color intensity, saturation or relative strength of color. Indicates the degree of departure from a gray of the same Value.
• The scale is from 0 ‐ 8 on the Munsell Color Chart. 0 indicates no strength (no color; gray) and 8 greatest strength (most color). Numbers are units of Chroma.
• Read from left (lowest) to right (highest).
CHROMA – strength of color
1 2 3 4 6 8
• Increasing strength of color (at same Value) Increasing grayness Chromameasurement Value of coloring measurement agents like of soil organic iron or matter (OM).
Is the lightness Strength of or darkness of color. Range a color. Range is from 0 (no is from 0 (pure color) to 8 black) to 10 (most color).
Low Chroma Colors
• Throughout this course you will hear the term “low chroma colors”‐ What does it mean?
Low Chroma means:
CHROMA 2 OR LESS
• All hues have chroma 2 or less on the pages, therefore all hues have low chroma colors.
• All Gley chart colors are comprised completely of low chroma colors.
• Specific low chroma colors have meaning regarding the SHWT determination (more on this later).
Colors BETWEEN Chroma Chips
• Colors exist between Chroma chips
• They are noted differently than others
• If the chroma is between two chips, note the lower one and add a “+” as a notation.
• Example: The soil has more color than 10YR 6/1 and not enough to be 10YR 6/2.
• The proper notation would be 10YR 6/1+ Colors BETWEEN Chroma Chips
• DO NOT ROUND UP TO THE NEXT HIGHERCHROMA.
• THIS IS ESSENTIAL WHEN DECIDING IF
SPECIFIC COLORS CAN BE USED AS AN
INDICATOR OF SEASONAL HIGH WATERTABLE (more later).
PROPER TECHNIQUE WHEN
DETERMINING SOILCOLORS Correct Coloring Method
• Hold soil behind the hue card with the color chips (the right side of the Munsell Book).
• Find the closest match from all choices in the book, read Hue Value/Chroma notation.
• Look to left side of Munsell book for soil color name and match Hue Value/Chroma from right side.
• See next slide for examples.
COLOR NAME DIAGRAM MUNSELL NOTATIONSWhen using the Munsell book Use the book properly – Pages must be usable!!!
• Do not take too long to read the color • Use the chip masks if necessary • Use the mask closest in value to the soil sample being • observed. Use black mask for black/very dark samples, white mask for light colored soil samples, gray for everything else.
• The use of a chip mask will facilitate color matching when there is difficulty in choosing a color. The mask allows only 4 chips to be seen at one time. Located inside the back cover of the Munsell Book.
CHIP MASKSReading soil colors
• Optimum conditions – Natural light – Clear, sunny day – Midday – Light at right angles – Soil is moist (not wet or dry) Moist Soil
• A moist sample will not get any darker when water is added to the sample, and it will not glisten. A sample that is too wet will glisten in the sunlight, or the water puddles on the sample.
• When texturing, the soil should be easily manipulated by your thumb and forefinger.
• In non‐sandy soils, this could be compared to moist putty.
Correct Moisture Content
Sample NOT THE RIGHT WAY!!!
Different types of Colors:
The GLEY charts These are read differently than the other charts
• Two supplemental charts containing grayish, bluish and greenish colors often found in very wet mineral soils are contained on these charts. The charts also contain a Neutral Hue (no chroma). Soils with specific colors on these charts are very wet and will be discussed in a separate presentation.
The Gley Charts Hues are found in EACH INDIVIDUAL COLUMN at the bottom of the page.
Values are on left, like other charts.
Values on left side Different Hues on bottom What about the CHROMA for the Gley Charts?
• Read chroma from the English name (left side) of the charts. Chroma designation will be to the right of the forward slash. See next slide.
Read Chroma from right of forward slash NO CHROMA Note that all hues on the Gley Charts are chroma 1, except for
• N (Neutral) having 0 (no) chroma (this is due to lack of iron giving any color), and • 5G _/2.
Examples of Munsell Books Which Munsell books/Hue cards you should and should not use (how to know when to get a new Hue card or new book) Some of the problems
• Values or chromas have changed within the same hue between editions
• Addition of new hues
• Missing chips
• Dirty chips (no longer are correct color)
• Cracked/faded/discolored chips
• Chips taped to page
• The pages have been laminated.
• The book has been left in the rain and has mildewed, obscuring the colors.
Two 10R pages from different years. Note new chips.
New columns of color This column This is really deleted a new row Taped chips, missing chips, cracked chips, discolored (dirty/faded) chips. Older page on left, new on right.
Comparison of 2 cards (New behind old, look at differences in colors) Use of the older cards would result in misidentification of soil colors, including the SHWT identification features, which will result in improper determination of the SHWT.
Soil Color Contrast Determining Differences between soil colors Hue Difference
• First must determine the difference in the HUES of each color
• Should use color wheel (later slide)
• Quick method for most colors is to count pages in accordance with following diagram. (Note: Δ signifies “change in” and “h” signifies Hue; therefore Δh means change in Hue) ∆h≠1 per page. Count # of 2.5-unit intervals.
∆h=1 per page, count # of pages Use of the Munsell Hue Circle USDA NRCS Technical Note 2 The hues shown in RED are the approved soil hues.
• To determine the "difference in hue" between colors, COUNT THE NUMBER OF 2.5‐UNIT INTERVALS.
• For example, hues of 2.5YR and 7.5YR differ by two 2.5‐unit intervals (7.5‐2.5=5, which is two 2.5 unit intervals), and so their difference in hue is counted as "2.“
• Hues of 5Y and 5GY differ by four 2.5‐unit intervals, and so their difference in hue is counted as "4.“
• Could also just use the wheel.
Hue change from Neutral
• The Hue change from
NEUTRAL to ANY OTHER HUEis a change of ONE UNIT OF HUE.
Units of Value Change
• Units of value range from 0 to 10. Normally, there is a one unit change between each color, but there may be less.
• For example:
The difference in Value between a 10YR 5/1 and a 10YR 7/1 is 2 UNITS.
(The difference between 5 and 7 is 2.)
• Here, the values can change as little as 0.5 units within the same chroma.
• The difference between a value of 2.5 and a value of 3 (both at chroma 1) is 0.5 units (1 unit of value change). If you were to count chips, the answer would be different, where the wrong answer would be a difference of 1 chip.
• TO DETERMINE VALUE CHANGE,
BETWEEN THE UNITS(Value of 2.5, 3, 4, etc.) –
DO NOT COUNT CHIPS !!
Units of Chroma Change
• Units for Chroma range from 0 to 8. There is a one or two unit change between each color.
1 UNIT CHANGE/CHIP 2 UNIT CHANGE/CHIP VERY IMPORTANT!!!