This document discusses soil texture classification using a ternary diagram. It begins by defining soil and describing its components of solids, liquids, and gases. Soil texture is determined by measuring the percentage of sand, silt, and clay particles. A ternary diagram is introduced as a triangular chart used to plot levels of the three components to determine the soil type. Sample soils are given with percentages of sand, silt, and clay, which could be plotted on the ternary diagram to classify the soil type based on its textural components. The document serves to explain soil texture analysis using a ternary diagram approach.

1. Determination of Soil Type by
Ternary Diagram textural plotting
Mithun Ray
Department of Geography
Malda College (University of Gour Banga)
E-mail: mithunmc@maldacollege.ac.in

2. What is Soil?
The unconsolidated mineral or organic
material on the immediate surface of the
Earth that serves as a natural medium for
the growth of land plants.
Soil is a natural body comprised of solids (minerals and organic matter), liquid,
and gases that occurs on the land surface, occupies space, and is characterized
by one or both of the following: horizons, or layers, that are distinguishable from
the initial material as a result of additions, losses, transfers, and transformations of
energy and matter or the ability to support rooted plants in a natural environment.

3. Texture is the disposition or
manner of union of the particles
of a body or substance, a visual
or tactile surface characteristic
resulting in a certain
appearance.
What is Texture

4. Grain Size
Classification
Chester K. Wentworth in a 1922 article in The Journal of Geology:
"A Scale of Grade and Class Terms for Clastic Sediments".

5. Soil Texture
Soil texture is determined by the
relative amounts of three groups
of soil particles or soil separates.
The three soil
separates are sand, silt, and clay.
Texture provides a means to
physically describe soil by feel or
by measuring the proportion
(percentage) of the three soil
particle size ranges.

6. SOIL CHARACTERISTICS RELATED TO TEXTURE
The texture of a soil is important because it determines soil characteristics that
affect plant growth.
Three of these characteristics are water-holding capacity, permeability, and soil
workability.
Water-holding capacity is the ability of a soil to retain water. Most plants require a
steady supply of water, and it is obtained from the soil. While plants need water,
they also need air in the root zone.
Permeability is the ease with which air and water may pass through the soil.

7. Soil workability is the ease with which soil may be tilled and the timing of the
work.
Soils with large percentages of sand are easier to work than soils with large
percentages of clay. Clay soils tend to be tighter, making them more difficult to
break up or cultivate, whereas sandy soils are looser. A clay soil also takes
longer than a sandy soil to dry after a rain. Because of the better drainage, a
sandy soil can be worked sooner. With a wet clay soil, the producer or gardener
must wait longer for the soil to dry sufficiently.
Soil texture may limit which crops can be grown. For example, root crops, such
as carrots and onions, perform best in a sandy soil because it is loose and allows
the plants to expand. On the other hand, some crops may experience stunted
growth in a sandy soil because the soil lacks water- and nutrient-holding ability.

9. Classification of particles
according to size
United States Department of
Agriculture (USDA)

16. Ternary Diagram
A ternary diagram is a triangular coordinate system; the edges of the triangle are
the axes. Ternary diagrams are used to plot three dependent variables that
always add up to a fixed value, for example, to visualize the compositional
variations of rocks or minerals.

17. Determination of Soil Type by
Ternary Diagram textural plotting

19. 100 90 80 70 60 50 40 30 20 10 0
Percent Sand

22. Sample Sand (%) Silt (%) Clay(%)
A 20 30 50
B 50 35 15
C 45 20 35
D 30 40 30

23. This Power Point Presentation (PPT) has been
prepared only to deliver the lecture. The
materials (Maps, Diagrams and Images) used in
this presentation have been collected and
compiled by the presenter from various
academic blogs, research papers, books etc.

24. THANK YOU