Friday we ended class talking about the physical properties of soil. We learned that these soil properties are very important because they help us determine what type of soil we are dealing with. Some of these physical properties of soil include soil color, soil texture, soil structure, and soil compaction.
Color is a major pyhsical property of soil. The three main colors of soil are red, black, and white. These colors varry in different geogrpahic regions. Red soils are the most local, commonly found in the Southeastern United States. These soils are mostly formed from iron that has been highly oxidized through time. Black is the next major color and it is usually associated with the amount of organic material in the the soil. The more organic material in the soil, the darker the soil. These dark soils also hold water better which allows for a healthier microbial community. Lastly there is white or off-white soil color. White soils have a high sand content and contain a high ammout of quartz.
The next physical property is the most important and that is soil texture. Soil texture is the percent of sand, silt, an clay in a certain soil. If you only knew the texture of the soil it would give you the best chance to classify it. Knowing the texture of the soil will give you important information about the soil compacity, flow potential, and fertility potential. Fine textured soils hold more water than coarse soils, but medium coarse soils are most suitable for crop growth.
Soil structure is next major physical property of soil. Soil structure is the arrangement of different particles in the soil. These particles can differ in size, shape, and orientation. Soil structure is very important and helps us determine the ammount of porous space in the soil. “There are four main types of soil structure.” The first is “platy structure which is thin, layered soils associated with ponding.” Next there is the “prismatic structure which looks like verticle columns and is related with arid soils.” After that there are “blocky structures which are cube-like and found in humid regions.” Lastly there are “spherical structures which is made up of round particles, no larger than sand, and is mostly found in highly organic soils.”
The last major physical property of soil is soil compaction. This property associated with the restricted aeration of soil. This is caused by poor drainage and effects how deep the roots of plants can pentrate into the soil. Compaction of soil can cause an increase in soil run-off, soil erosion, and anarobic conditions that greatly reduce soil fertility. To reduce the amount of soil compaction one must increase the amount of organic material or simply just stop putting increased force on that area.
These are just some of the important physical properties of soil that I found related to what we have been talking about in class.
- Soil in the Environment: Cruciable of the Terrestrial Life By: Daniel Hillel