Soil Texture

1. Soil Texture
Soil Physics
PhD-I
Presented By: Muhammad Usman
Course Instructor: Dr. Jalil ur Rehman

2. SOIL TEXTURE

3. • The look and the feel of a soil is referred as soil
texture which is determined by the relative proportion
of mineral particles of different sizes present in the
soil.
• Soil are composed of sand, slit and clay particles.
• Stones and gravels are excluded from the textural
classes.
Soil Texture

4. • Particle size is determined by the diameter of
individual soil fragments.
• According to the International system of soil
classification ,size of different particle are as
follows:
• Clay – less than 0.002 mm
• Slits – 0.002mm to 0.02mm
• Sand – 0.02mm to 2.0mm
Size of the Particles

5. • very fine sand – 0.02mm to 0.10mm
• Fine sand – 0.10mm to 0.25mm
• Medium sand – 0.25mm to o.50mm
• Coarse sand – 0.50mm to 1.0mm
• Very coarse sand – 1.0mm to 2.0mm
• Gravel - larger than 2.0 mm
Size of the Particles

6. Textural Classes of Soils

7. SOIL TEXTURAL PYRAMID : describing the relative
proportion of sand ,slit ,clay in various type of soils.

8. Properties
 Loamy soil are a balance between sand , slit and clay particles and
considered as the most desirable soils for agricultural.
 Sandy soil have coarse texture. They hold water and mineral poorly . Water
and air penetrate easily thats why, they warm readily in spring and cool
quickly in autumn.
 Clayey soil hold large volume of water and retain minerals . They are very
slow to warm in spring and cool more slowly in autumn.
 Slity soil are intermediate in characteristics and properties between sandy
and clayey soil.

9. • Sand and slit are generally irregular in shape, ranging from rectangular or
blocky to, spherical shapes.
• Clay particles are made up of two to three flat crystalline plates , layered or
laminated together. These particle can be hexagonal in shape with distinct
edges , or they may form irregularly shaped flakes or even rods.
• Allophane (an amorphous material ) have same tiny size as clay particle and
is prevalent in soils developed from volcanic ash.
Why different Soil Textures have the
Properties they do?

10. Role of Soil Texture
• Soil texture is a qualitative classification tool used in both the field and
laboratory to determine classes for agricultural soils based on their physical
texture.
• It directly influences soil-water relationship, aeration and root penetration
through its relationship with interpartical pore space.
• Soil texture is of ecological interest, for the dominant particle size present in
any area have an effect on the flora and fauna of an area.

11. Role of Soil Texture
• It affects the nutritional status of soil.

12. Thank You
Any Question?