Soil Triangle and Some Problems to Solve Before Class

Attempt to do the following exercises BEFORE class.  We'll recap in class!  

Your Name ________________________

Using the Soil Texture Triangle

Follow these steps to determine the name of your soil texture:

1. Place the edge of a ruler or other straight edge at the point along the base of the triangle that represents the percent of sand in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.

2. Place the edge of a second ruler at the point along the right side of the triangle that represents the percent of silt in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.

3. Place the point of a pencil or pen at the point where the two lines meet. Place the top edge of one of the rulers on the mark, and hold the ruler parallel to the horizontal lines. The number on the left should be the percent of clay in the sample.

The descriptive name of the soil sample is written in the shaded area where the mark is located. If the mark should fall directly on a line between two descriptions, record both names.

Sand will feel "gritty", while silt will feel like powder or flour. Clay will feel "sticky" and hard to squeeze, and will probably stick to your hand. Looking at the textural triangle, try to estimate how much sand, silt, or clay is in the sample. Find the name of the texture that this soil corresponds to.

Practice Exercises

Use the following numbers to determine the soil texture name using the textural triangle. When a number is missing, fill in the blanks (the sum of % sand, silt and clay should always add up to 100%) - the last line has been left blank for you to fill in the numbers you assign to your own soil sample.

% SAND	%SILT	%CLAY	TEXTURE NAME
75	10	15	sandy loam
10	83	7
42		37
	52	21
	35	50
30	55
37		21
5	70
55		40
	45	10

The Soil Triangle and Questions (Apologies for its lateness!)

We will cover this in class.  The following is a set of practice questions you can use to determine your ability to use the Soil Triangle.  This is not an assignment you need to turn in. 

Using the Soil Texture Triangle

Follow these steps to determine the name of your soil texture:

1. Place the edge of a ruler or other straight edge at the point along the base of the triangle that represents the percent of sand in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.

2. Place the edge of a second ruler at the point along the right side of the triangle that represents the percent of silt in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.

3. Place the point of a pencil or pen at the point where the two lines meet. Place the top edge of one of the rulers on the mark, and hold the ruler parallel to the horizontal lines. The number on the left should be the percent of clay in the sample.

The descriptive name of the soil sample is written in the shaded area where the mark is located. If the mark should fall directly on a line between two descriptions, record both names.

Sand will feel "gritty", while silt will feel like powder or flour. Clay will feel "sticky" and hard to squeeze, and will probably stick to your hand. Looking at the textural triangle, try to estimate how much sand, silt, or clay is in the sample. Find the name of the texture that this soil corresponds to.

Practice Exercises

Use the following numbers to determine the soil texture name using the textural triangle. When a number is missing, fill in the blanks (the sum of % sand, silt and clay should always add up to 100%) - the last line has been left blank for you to fill in the numbers you assign to your own soil sample.

% SAND	%SILT	%CLAY	TEXTURE NAME
75	10	15	sandy loam
10	83	7
42		37
	52	21
	35	50
30	55
37		21
5	70
55		40
	45	10

A Soils Bibliography

Out of the Earth: Civilization and the Life of the Soil; ©1992 University of California Press , Hillel, Daniel. Hillel has written one of the most beautiful books on soil that has ever been published. This book introduces a little of soil science to the reader, but more than that, it fosters a love of the soil and an understanding about the magnitude and gravity of misuse and degradation; civilizations have paid little heed to the soil underfoot and it has cost them dearly. A delightful read!

Soils and Men, Yearbook of Agriculture 1938, © 1938, United States Department of Agriculture, The Committee on Soils. A government publication, no sane person will read from beginning to end! It is referenced here because it clearly shows the US government knew about the soil food web as early as 1938 and chose to ignore that information in favor of more commerce in chemical based fertilizers. We are at a point where ignoring the soil food web is too costly to continue.

Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web, Revised Edition, © 2010 Timber Press, Lowenfels, Jeff and Lewis, Wayne. This is the second edition of the book that blew my eyes open on the biology of the soil and how we cannot ignore that biology plays at least as big a part of soil fertility as chemistry. We ignore biology to our own detriment and destroy our soils.

The Rodale Book of Composting, ©1992 Rodale Press, Martin, Deborah and Gershuny, Grace Editors. This is the only book to read on composting. Everything else is compostable.

The Soul of Soil; A Guide to Ecological Soil Management, 2nd Edition, ©1986; Gaia Services, Gershuny, Grace. This fabulous and passionate book is injured by being targeted to farmers (only) and therefore all recommendations are written in “pound per acre,” when we need ounces per 100 square feet. When I used this book, I wrote up a formula in Excel to convert all these into a usable figure.

The Worst Hard Time, The Untold Story of Those Who Survived The Great American Dustbowl © 2006; Mariner Reprint Edition, Egan, Timothy. Not strictly a soils book, but a real eye opener that shows how we are repeating many of the same mistakes today as what lead to the disaster we call the Dustbowl. This book is gripping reading and is not fiction. It really happened and it happened on a scale unprecedented in modern times. We can do it again if we fail to heed these words. A VERY good read on soils and man's relationship to them.

The Soil Triangle and It's Use

Taking soil samples for any kind of garden analysis should be done in a manner that will net you the results you need to make your garden more congenial to that part of the plant that lives in the soil – the roots. Roots for most of the plants in our gardens, live about 4 to 18 inches beneath the surface of the soil. Exceptions to this include most drought resistant plants (with roots that range some distance out and down) and other notoriously strong rooted plant – mention just about any weed and it will fall into that category. You want to take your sample around nine inches down. This method of taking a soil sample is effective for the soil triangle tests and is the preferred technique for soil samples sent to labs for testing.



What to do and How to do it
Follow these steps to determine the name of your soil texture:
1.Place the edge of a ruler at the point along the base of the triangle that represents the percent of sand in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
2.Place the edge of a second ruler at the point along the right side of the triangle that represents the percent of silt in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
3.Place the point of a pencil or water soluble marker at the point where the two rulers meet. Place the top edge of one of the rulers on the mark, and hold the ruler parallel to the horizontal lines. The number on the left should be the percent of clay in the sample.

4.The descriptive name of the soil sample is written in the shaded area where the mark is located. If the mark should fall directly on a line between two descriptions, record both names.

• Remove as much surface organic matter as possible before taking your soil sample.
• Put approximately one cup of soil into a straight-sided quart jar with lid.
• Add approximately one tablespoon of alum or Calgon bath beads – this is a surfactant to help the particles separate from one another.
• Fill the jar with water almost to the top.
• Shake vigorously for several minutes to get all the soil moistened. 
• Let the jar stand undisturbed for at least one hour, separation continues for as long as 24 hours with some soils.
• The soil mix will separate into layers. The longer it sits, the more distinct the layers will appear.
  Determine soil type by comparing percentages with soil triangle. Follow arrows, for example—15% sand, 70% silt, and 15% clay—to merge at silty loam category.
  
  

  Practice Exercises:

  Use the following numbers to determine the soil texture name using the textural triangle. When a number is missing, fill in the blanks (note: the sum of %sand, silt and clay should always add up to 100%):

  
  

  % SAND	%SILT	%CLAY	TEXTURE NAME
  75	10	15	sandy loam
  10	83	7
  42		37
  	52	21
  	35	50
  30	55
  37		21
  5	70
  55		40
  	45	10

  
  

  
  
  
  
  Sand will feel "gritty", while silt will feel like powder or flour.
  Clay will feel "sticky" and hard to squeeze, and will probably stick to your hand.
  Looking at the textural triangle, try to estimate how much sand, silt, or clay is in the sample.  
  Find the name of the texture to which this soil corresponds; that will be the descriptive name of your soil.
• Understanding soil type will help you know how to properly amend, fertilize, water, and plant so that you will have healthy, disease-resistant, and pest-resistant plants.
• Figure out the percentages of sand, silt, clay, and organic matter in the water – do not measure the water itself. The sand will be the bottom layer. Silt will be the next layer, followed by clay; the combination of these three should add up to 100%. Organic matter will float on top of the water and does not figure in the total of percentages.

All of your figures, clay + sand + silt will equal 100% or you have done something wrong. Remember, this simple knowledge of your soil will enable you to predict how it will interact with your plants and will determine a great deal about how you need to interact with your soil.

How To Take A Soil Sample and Read The Soil Triangle

Taking soil samples for any kind of garden analysis should be done in a manner that will net you the results you need to make your garden more congenial to that part of the plant that lives in the soil – the roots. Roots for most of the plants in our gardens, live about 4 to 18 inches beneath the surface of the soil. Exceptions to this include most drought resistant plants (with roots that range some distance out and down) and other notoriously strong rooted plant – mention just about any weed and it will fall into that category. You want to take your sample around nine inches down. This method of taking a soil sample is effective for the soil triangle tests and is the preferred technique for soil samples sent to labs for testing.

• Remove as much surface organic matter as possible before taking your soil sample.
• Put approximately one cup of soil into a straight-sided quart jar with lid.
• Add approximately one tablespoon of alum or Calgon bath beads – this is a surfactant to help the particles separate from one another.
• Fill the jar with water almost to the top.
• Shake vigorously for several minutes to get all the soil moistened. 
• Let the jar stand undisturbed for at least one hour, separation continues for as long as 24 hours with some soils.
• The soil mix will separate into layers. The longer it sits, the more distinct the layers will appear.
  
  
  Figure out the percentages of sand, silt, clay, and organic matter in the water – do not measure the water itself. The sand will be the bottom layer. Silt will be the next layer, followed by clay; the combination of these three should add up to 100%. Organic matter will float on top of the water and does not figure in the total of percentages..  
  Determine soil type by comparing percentages with soil triangle.
  
  Understanding soil type will help you know how to properly amend, fertilize, water, and plant so that you will have healthy, disease-resistant, and pest-resistant plants.
  
  What to do and How to do it
  
  Follow these steps to determine the name of your soil texture:
  
  1.Place the edge of a ruler at the point along the base of the triangle that represents the percent of sand in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
  
  2.Place the edge of a second ruler at the point along the right side of the triangle that represents the percent of silt in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
  
  3.Place the point of a pencil or water soluble marker at the point where the two rulers meet. Place the top edge of one of the rulers on the mark, and hold the ruler parallel to the horizontal lines. The number on the left should be the percent of clay in the sample.
  
  4.The descriptive name of the soil sample is written in the shaded area where the mark is located. If the mark should fall directly on a line between two descriptions, record both names.
  
  Feel the texture of a moist soil sample between your fingers.
  Sand will feel "gritty", while silt will feel like powder or flour.
  Clay will feel "sticky" and hard to squeeze, and will probably stick to your hand.
  Looking at the textural triangle, try to estimate how much sand, silt, or clay is in the sample.
  Find the name of the texture to which this soil corresponds; that will be the descriptive name of your soil.

david

Using The Soil Triangle

Using The Soil Triangle 

Follow these steps to determine the name of your soil texture:

1. Place the edge of a ruler at the point along the base of the triangle that represents the percent of sand in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
2. Place the edge of a second ruler at the point along the right side of the triangle that represents the percent of silt in your sample. Position the ruler on or parallel to the lines which slant toward the base of the triangle.
3. Place the point of a pencil or water soluble marker at the point where the two rulers meet. Place the top edge of one of the rulers on the mark, and hold the ruler parallel to the horizontal lines. The number on the left should be the percent of clay in the sample.
4. The descriptive name of the soil sample is written in the shaded area where the mark is located. If the mark should fall directly on a line between two descriptions, record both names.

Feel the texture of a moist soil sample. Sand will feel "gritty", while silt will feel like powder or flour. Clay will feel "sticky" and hard to squeeze, and will probably stick to your hand. Looking at the textural triangle, try to estimate how much sand, silt, or clay is in the sample. Find the name of the texture that this soil corresponds to.

Practice Exercises:

Use the following numbers to determine the soil texture name using the textural triangle. When a number is missing, fill in the blanks (note: the sum of % sand, silt and clay should always add up to 100%):

% SAND	%SILT	%CLAY	TEXTURE NAME
75	10	15	sandy loam
10	83	7
42		37
	52	21
	35	50
30	55
37		21
5	70
55		40
	45	10

From: http://www.hwr.arizona.edu/globe/globe2/soilpb42.html