LFS:SoilWeb/Soil Components
| SoilWeb Learning Resource | |
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| Land and Food Systems | |
| Welcome to the wiki for SoilWeb200. The SoilWeb200 learning resource provides students with text, graphical and interactive web-based information to assist them in learning the connections among a large number of concepts and to relate them to various soil management issues as presented in the course APBI 200 - Introduction to Soil Science. | |
| Associated Pages | |
Although numerous substances can be found in soils, they can be categorized into four major components:
- mineral or inorganic,
- organic,
- water, and
- air.
The relative proportions of these four soil components vary tremendously. Mineral soil, under optimal conditions for plant growth, has proportions of the four soil components (by volume) as indicated in the figure below.
Please note that the ratio of air and water in soil often changes seasonally, weekly, and even daily, depending on water inputs through precipitation or groundwater discharge. Organic matter content varies among soil types and in some mineral soils it can be much lower than 5%, while some Organic soils (found in bogs and other wetland areas) have considerably more organic matter(greater than 50% of the solid portion by volume).