There’s a few different ways to classify soils:
- By soil order
- By texture/traits/characteristics/particle size
- By color
- By region or zone
- By biome
- Miscellaneous soils
In this guide, we outline how each soil can be classified in these different ways, and give a description of each soil type as well.
The Different Types Of Soils – Summary
The reality is that there are thousands of different types of soils that can be broken down into the main groups, sub groups, great groups, families, series’ and so on.
They all vary in color, texture, structure, and chemical, physical, and biological composition.
That can all get really confusing and in depth, so instead, below are the main ways that the main soil types might be classified or identified in a more simple way to everyone – experts, farmers and the average person.
There are 12 different soil orders. They are:
- Alfisols – moderately weathered. 10% of global ice free land
- Andisols – volcanic ash. 1% of global ice free land
- Aridisols – very dry. 13% of global ice free land
- Entisols – newly formed. 16% of global ice free land, and the largest soil type of all
- Gelisols – frozen. 9% of global ice free land
- Histosols – organic, wet. 1% of global ice free land
- Inceptisols – slightly developed (young). 10% of global ice free land
- Mollisols – deep, fertile. 7% of global ice free land
- Oxisols – very weathered. 7.5% of global ice free land
- Spodosols – sandy, acidic. 2.5% of global ice free land
- Ultisols – weathered. 8.5% of global ice free land
- Vertisols – shrink and swell. 2.5% of global ice free land
There is a world map of the different soil orders and where they can be found at https://www.soils4teachers.org/around-the-world
Read in more depth about the different soil orders at:
The above soil orders also have suborders, each of which are listed at https://globalrangelands.org/topics/rangeland-ecology/twelve-soil-orders
Soil Textures/Traits/Characteristics/Particle Size
Soil texture, traits and characteristics includes particle size and other features. Examples include:
- Sandy Soil – a light soil with large particle size. Because it has poor water retention and low nutrients, it’s not seen as a soil that is naturally good for plant life. Read more about sandy soils in this guide
- Clayey Soil – a heavy soil that is very good at water retention/holding water. Although can be a soil that’s rich in organic matter, it’s not good for growing lot of plants. Read more about clayey soils in this guide
- Silty Soil – has medium particle size. Is a light soil that holds water well. It’s fairly fertile, although some say it doesn’t hold nutrients as well as some other soils, and benefits from the addition of organic matter. Read more about silty soils in this guide
- Peat Soil – usually dark brown or black in color, high in organic matter (and low in nutrients), and holds water well – all qualities that make it good for a range of plants. Is usually an acidic soil or a soil that contains acidic water. Peat soil is commonly imported into gardens to provide a planting base. Read more about peat soil in this guide.
- Chalky Soil – can be a light or heavy soil, but is an alkaline soil because of the lime or calcium carbonate found in it. Doesn’t suit the growth of plants that need acidic or regular conditions to grow. Mineral can leach out of chalky soil quickly. Read more about chalky soil in this guide.
- Loam Soil – one of the best and most fertile soils for cultivation of plants and crops of many kinds – referred to as the ideal soil type. Contains consists of sand, clay, and silt – so it combines the best qualities of each. Has good aeration, but holds water well and also drains it well. Can benefit from topping up with organic matter. Read more about loam soils in this guide
Some say the best soil is a loam type soil that is 40 percent sand, 40 percent silt, and 20 percent clay as it’s fertile, but also has good water drainage, good moisture retention and allows good infiltration of air and water (dummies.com).
Read more on soil types by texture, traits and characteristics at:
- https://www.dummies.com/home-garden/gardening/urban-farming-how-to-determine-your-soil-type/ (Mention how soils can have different balances of different particles like sand, clay etc.)
You can also classify soil by pH:
Soils can be categorised by their color in many countries across the world. One such example is in India:
- Red Soil, & Yellow Soil – found in India. Red soil gets its colour from the iron found in its composition in a crystallized form. The soil takes on a yellow colour when it is hydrated. These soils are generally found in the Western Ghats, Odisha and Chattisgarh.
- Black Soil – These soil are rich in lime, iron and magnesia. They are mainly found in the Deccan Plateau in Maharashtra, Madhya Pradesh, Gujarat etc.
Read more about them at:
Note that there are many other examples of soils being calssified by color in countries other than India.
Soil Regions Or Zones
Sometimes soils are categorised according to the zone or region they are found in. This could be a type of landscape within a country, or a state or region within a state.
- Soils Of The Alpine & Perhumid Zones
- Soils Of The Humid Zones
- Soils Of The Seasonably Humid Zones
- Soils Of The Semi Arid Zones
- Soils Of The Arid Zones
Read more about them at: http://www.abs.gov.au/ausstats/[email protected]/Previousproducts/1301.0Feature%20Article801966
- Mountain Soil
- Arid Soil
Read more about them at:
The US has a representative soil for each of the 50 states.
You can read more about them at:
It’s not really a way to classify soils specifically, but it’s a way to classify where soils might be found according to biome.
Biome examples include deserts, shrubland, temperate forests, tundra and so on.
You can look at a world map of the different biomes at https://www.soils4teachers.org/around-the-world
Miscellaneous Soils, Or Other Soils
Soils can be classified specifically, or in a certain way, if people want to describe a soil that has a specific feature. Examples might include saline or alkaline soils.
7. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=stelprdb1236841 (state soils in the US)
15. – https://www.bettermeetsreality.com/the-different-soils-worldwide-in-different-countries-different-climates/
18. http://www.abs.gov.au/ausstats/[email protected]/Previousproducts/1301.0Feature%20Article801966