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Soil Orders

Updated: Aug 8, 2019

Depending on where you live, the particle size, and how old your soil is, depends on the type of soil that you have. In fact, worldwide there are 12 different orders of soils.

How are soils formed? A quick lesson on geology: the earth through her natural processes formed different types of rocks. As those rocks broke down over time due to wind or water erosion, rocks became the tiiiiiny particles within our soil. But when you scoop up dirt in your hand, you must know it doesn’t come from a single rock source. Soil is a mixture from varying rocks and other decomposing organic sources, which have come together. Soil truly is a changing living thing.

In fact the age of the soil makes a huge difference in how healthy it is. New soils also called “Entisols” typically are formed at the tops of mountains and haven’t had a lot of time to weather or become nutritional. Entisols tend be mixed with lots of rocks that are still breaking down and would not be recommended for good gardening soil. On the other hand older soils like “Ultisols” have had a lot of their nutrition pulled out or leached out. So—a good soil would be somewhere between these two extremes.

The best kinds of soils include “Mollisols” which have a rich and deep organic top layer. These soils are typically found in the Midwest of the United States. Although this is the most nutritional and easiest soil to work with, this doesn’t mean one should not use caution. Soils are sensitive and typically need diversity in their diets. If they get too much of one thing (whether that is years of having the same crop grow in it, or dumped with inorganic fertilizers over and over and over again), soils can start to get weary. This is yet another reason why microbes in your soil can help keep nutrients diverse.

What other kinds of soil types are there? Gellisols are frozen soils, often found in the Tundras of Alaska. Histosols are similar to Mollisols in the sense that they are organic but unlike Mollisols which have pronounced dry seasons, Histosols tend to be wet. Andisols are volcanic ash soils (very fertile), while Aridisols tend to be very dry. Vertisols shrink and swell because they have high clay content. These soils when dry may have large cracks that may be as deep as 3 feet down and a few inches across! Vertisols soils are typically found in Southern Texas.

If you live in the United States the highest percentage of soils is Mollisols, and then healthy Alfisols which together make up 34% of the US soils. We are blessed to live in a country with so much healthy soil. What kind of soil do you have? Do a search on the web and let us know!


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