SOIL TEXTURE

What is Soil Texture

• Soil texture is the _______ or ___________ of a soil. It describes the proportions of three sizes of soil.
• The three soil particles/separates classified according to size are _____, ______, or _____.
• _______ is the smallest sized particle.
• _______ is a medium sized particle.
• _______ is the largest sized particle.

Sand Texture

• Sand
• Sand
• Sand.

Silt Texture

• Silt
• Silt
• You can see silt
• When hand sampling,

Clay Texture

• Clay
• Clay
• It will stick

Soil Texture Identification Key Flow Chart

Using the identification key flow chart (same as identification keys used in science) students will identify the different soil textures by feel.

Land Judging Soil Texture Types

• For land judging, five texture categories are recognized as shown by the middle column of the Soil Texture table (refer to hard copy hand out).
• They are:____________,____________, ____________, _______________, _______________

Coarse Textured Soils

• Coarse-textured soils are loose, very friable, and the individual grains can be readily _____ or ______.
• When squeezed between ______ and _______, it feels gritty and will not ______ or stain fingers.
• Squeezed when _____, it will fall apart as pressure is released.
• When moist, a mold may be formed which is unstable and ________ as the soil is handled.

Moderately Coarse Soil

• Moderately coarse-textured soils feel ______ but contain enough _____ and ______ to make moist soil hold together.
• The individual _____ grains can readily be seen and felt.
• Squeezed when dry, it will form a mold which ________ readily upon handling.
• If squeezed when moist, a mold can be formed which can be carefully _______ without breaking. It forms no _______ or very poor ________.

Medium

• Medium-textured soils have a slightly _______ or _________ feel when moist.
• Squeezed when dry, it forms a mold that will bear careful ___________.
• The mold formed by squeezing when moist can be handled freely, without __________.
• When the moistened soil is squeezed out between the thumb and forefinger, it will form a poor ________ with a dull surface.

Moderately Fine

• Moderately fine-textured soils usually break into _______ or ______ when dry.
• When the moist soil is squeezed out between thumb and forefinger, it ______ with some effort.
• It will form a short (1 inch to 2 inch) well-formed _______ with a shiny surface which will tend to break or the ________ will bend downward.
• The ___________________texture has a slightly gritty feel when moist.

Fine

• Fine-textured soils form very ______, massive lumps or clods.
• When dry the soils are quite ______ and _________ when wet.
• When the moist soil is squeezed out between thumb and forefinger it _______ with considerable effort and will form a long (2 inch+) _______ which will support itself.
• The sandy clay texture may also have a slightly _____ feel when moist.

Soil texture assessment

• Students are to perform the ribbon test on five different soil types and submit the ribbons for evaluation.
• Students will identify the different soil textures and submit their results to the instructor.
• Students will explain their soil texture identification according to the questions asked on the data and interpretation sheet.

Soil Textural Triangle

• Soil can be classified with the use of a ______________________________.
• Soil texture is determined by the __________ of sand, silt, or clay that make up the soil.
• Soil texture can vary with depth and from one _____________ to another
• The soil textural triangle is called a ________________ in science. There purpose is to plot 3 different variables, most commonly minerals.

USDA Soil Textural Classification Triangle

USDA Soil Textural Classification Triangle

• The purpose is to show the ________ of the 3 components.
• Percentages for _______ are read from zero along the diagonal axis at the top to 100% at the lower right corner of the triangle.
• Percentages for ______ are read from zero along the bottom axis on the right to 100% at the lower left of the triangle.
• Percentages for ________ are read from zero along the diagonal axis on the left to 100% at the highest point of the triangle.

USDA Soil Textural Classification Triangle

• Using the Textural Triangle calculate what type of soil we have if: there is 40% silt, 35% sand, and 25% clay .
• If: there is 60% silt, 25% sand and 15% clay
• If: there is 80% silt, 10% and and 10% clay
• If: there is 15% silt, 47% sand and 38% clay