Editing Soil

== Explanation ==
The soil is the topmost layer of the surface of the [[Earth]] that is filled with rocks, minerals, organic and inorganic matters, [[water]], [[air]] and other substances that make [[life]] possible. Soil comes in different textures and is used for various purposes. One of the main purposes of the soil is to provide a medium for [[plant]]s to facilitate [[water]] and [[nutrient]] supply to the [[root]]s. Soil also plays a vital role in the [[water cycle]], as it enables the rainwater to infiltrate into the ground.

== Frequently Asked Questions ==
=== How did the soil form? ===
Soil mainly form from both physical and chemical weathering of different types of rocks over a certain period. The rocks could be [[igneous rock]]s, [[metamorphic rock]]s, or [[sedimentary rock]]s. The other factors that contribute to the breakdown of rocks are the biological processes like plant growth and human activities. Based on the primary activities in different regions and weather, soil is diversely distributed around the world.

=== What are the classifications of the soil? ===
Soil is typically classified based on the size of the particles and texture as [[sand]], [[silt]], and [[clay]]. Sand particles are relatively big in size and have high [[porosity]]. Silt are quite medium in size, usually found in a water body like a [[river]] or [[lake]]. Clay is relatively small and smooth with no porosity. As any sample of soil will be diverse enough to have different textures, a texture chart is usually used to determine the type of soil.

In a more technical sense and engineering practices, we follow standardized soil classification systems adopted from the Unified Soil Classification System. For example, the Indian Standard Soil Classification System classifies the soil as follows.

{| class = wikitable
! rowspan="2" | Very coarse soil
| Boulder
| 
| greater than 300 mm
|-
| Cobblestone
| 
| 80 to 300 mm
|-
! rowspan="5" | Coarse soil
| rowspan="2" | Gravel - G
| Coarse
| 20 to 80 mm
|-
| Fine
| 4.75 to 20 mm
|-
| rowspan="3" | Sand - S
| Coarse
| 2 to 4.75 mm
|-
| Medium
| 0.425 to 2 mm
|-
| Fine
| 0.075 to 0.425 mm
|-
! rowspan="2" | Fine soil
| Silt - M
| 
| 0.002 to 0.075 mm
|-
| Clay - C
| 
| lesser than 0.002 mm
|}