This article aims to answer any questions you may have about desert soil. We will discuss the uses of desert soil types and their physical traits, and also take a look at how deserts vary between the dry climates around the world. A lack of nutrients is common, but other aspects also determine the fertility or infertility of these desert soils.
Click here to learn about other types of soil and their chrectaristics.
Desert Soil Physical Properties
The physical properties and appearance of deserts can depend on the type, location, climate, minerals, and other environmental factors. Desert soil characteristics, which generally apply to any type of desert soil, include (but are not limited to) a mostly sandy soil composition, very little moisture, and lack of nutrients.
Some desert soils do have the necessary desert soil nutrients to provide a haven for succulents and other desert plants and animals, but most of the vast deserts in the world have zero vegetation for miles in some places. This has to do with the climate in those regions and the fact that most desert soils tend to have slightly to highly basic soil pH levels which has a negative effect on nutrients that plants need to grow.
A desert soil’s nutrients, or lack thereof, can contribute to its physical appearance and feel. For instance, a nutrient-rich, moist, desert soil will have a thick texture and almost dirt-like appearance, while dry, infertile desert soils can blow away in the wind and are practically all sand.
Desert Soil Texture
The texture of a type of soil depends on three things – sand, silt, and clay. Some types of soil have mostly clay, while others, such as desert soils, have mostly sand. Typically, a soil that can allow plants to thrive contains equal parts of at least two of those factors. Garden soils often have equal parts of silt and sand or a generous combination of all three.
When it comes to deserts, 90-95% of their composition is sand.
Deserts are unique because of how it can still maintain life in some regions, even without a load of nutrients and water on standby. The physical texture of desert sand is dry and coarse, with large particles that come from eroded rocky parent materials.
Desert Soil Composition
There are four basic components of soil – minerals, water, air, and organic material (plant and animal matter).
Various regions around the world have different types of sand, each with a unique composition. This variation is due to the differences in climate and parent materials that first begin to form the sandy soils.
Many deserts contain minerals in the sand, such as quartz, feldspar, and mica. Desert soil has very little moisture content. Water in the desert sand depends entirely on nearby desert water sources, which are often scarce.
Desert plants, like cacti, store an excess of water since the desert soil does not provide much, thus making cacti and other desert plants drought tolerant.
Deserts also have a low amount of organic material. Since water is a rare occurrence in deserts, fewer animals are living in them and thus, less decomposing organisms. Soils that are rich in organic material are more life-sustaining.
Air is abundant in desert soils. Air in-between the sand particles is what allows the desert sand to fall easily between your fingers and be picked up so easily by the wind. Thick, black soil has less air in its composition because it is compacted with a high amount of water and organic matter.
Desert Soil Colors
Some deserts have red sand, some have white, and some are golden-brown. Desert soil takes on the color of the sand it contains. The color itself comes from its mineral content. Red sand soils have high levels of iron, desert soil from white sand typically has gypsum, and yellow sand soils have quartz.
Desert Topography
Topography refers to the small elevations on the Earth’s surface. This includes hills, plateaus, mountains, valleys, and any organic structure that protrudes from (or idents into) the ground. Surveyors can determine the exact topography of an area using a topographic survey and interpret it into a topographic map.
In areas of desert soil, the most common topographic features on the land are dunes, mountains, and desert flats.
Dunes
Dunes are one of the most recognizable features in the desert. Dunes form when the wind picks up sand and carries sand across the desert until it accumulates into hills. Widespread areas or “seas” of dunes are called ergs.
Most dunes consist of loose sand, but some can contain other materials, such as organic matter. Deserts have all variations of desert soil, and some areas contain a greater portion of pure sand than others.
Mountains
Deserts commonly have inselbergs or isolated rock masses. Inselbergs resemble the mountains you can see in other regions, but they have an entirely different composure because of being made from sandstone and other desert soil rocks.
Desert Flats
Most deserts have areas of flat desert soil. These desert flats occur because of the lack of living things in the area. You may see cacti, birds, and other small desert animals, but most desert flats are virtually without living organisms.
Watercourses
Deserts can get less than 10 inches of rainfall each year. The rainwater travels fast through the desert and rarely accumulates into bodies of water.
Water drainage in the desert soil is much different than in brown gardening soils. There are very few times of the year in which rainwater builds up enough to form a stream. The rest of the year, it dries to create watercourses, which have steep sides and jagged ravines in the ground that go through rocks.
Desert Soil Formation
Soil Horizons
Soil horizons are the visible layers in soil that show when you collect a profile. Soil profiles are vertical extractions from the ground that include bits of soil from all ranges of depth. Each visible layer is one of the 6 soil horizons – O, A, E, B, C, and R.
These soil horizons give hints into the desert soil formation. The identification of the different horizons that are in a soil profile can be informative to a soil scientist (pedologist) of the origins of soil, its organic content, and its classification.
Desert Soil Layers
The horizons in a desert soil profile show the different types of sand, rock, and minerals that have formed the soil over time. The horizons in a desert soil usually start with a hard desert pavement as the top layer – most desert soils are dry, and so the surface remains compacted and brittle.
Below the thin first layer of humus, the layers of the desert soil usually include thick, dry accumulations of clay, calcium carbonate, and soluble salts, along with a rocky parent material. There is an exception for arctic desert soils that have a layer of permafrost deep in the soil.
Types of Desert Soil and Their Uses
Different soil types have different properties and therefore each soil type is good for different uses. Deserts have aridisols and entisols.
Aridisols are dry, desertlike soils with low organic content. They are categorized by minimal vegetation and drought-tolerant plants. Most soils in deserts of the world are aridisols.
Entisols are much like aridisols since they are present in extreme temperatures. The only difference between the two is that entisols form with an absence of soil horizons. While other soils have multiple layers, entisols have the majority of horizon A under the surface. Entisols also occupy 11% of the nonpolar continental land surface of the Earth.
There is more than one type of desert soil. Desert soil types include subtropical desert, semiarid, coastal, and polar.
Subtropical and Tropical Desert Soil
Subtropical deserts are hot and dry. There are low humidity levels and severe swings in temperature. The gap between the low and high points of the day can be as extreme as 80o F. And, because of the extreme fluctuations in weather, water evaporates from the desert soil extremely quickly.
Sandy soils found in subtropical deserts are similar to the ones in tropical deserts.
The tropical sandy soils in tropical deserts have less than 18% clay, and at least 68% sand and are hardsetting soils, which means that it becomes hard and structureless when dry and thus is nearly impossible to cultivate. Desert sandy soils are already difficult to cultivate, no matter what type, but hardsetting desert soils are even more problematic.
Although tropical soils are lacking in most nutrients, the application of nitrogen can make it possible to produce rice crops. Subtropical and tropical desert soils are often similar to rainforest soil.
Semiarid Deserts
Semiarid deserts, also called Cold Winter deserts, are dry and have moderately low temperatures compared to other types of deserts. Semiarid desert temperatures usually do not rise above 100o F.
Cacti grow well in semiarid desert regions. Other desert plants such as creosote bush, bur sage, whitethorn, catclaw, mesquite, and brittle bushes, all provide shade for the small animals that live in semiarid deserts.
Coastal Deserts
Coastal deserts have low to moderate temperatures, cool winters, and warm summers. Organisms thrive better in coastal deserts than most other types of desert soil.
The rainfall in this type of desert is the same as most other deserts staying at an average of 8 to 13 cm of rain per year. However, the soil is higher in nutrients and contains excess salt, allowing plants such as saltbush, buckwheat bush, black bush, rice grass, black sage, and Chrysothamnus (rabbitbrush) to grow. These plants have many uses for medicine and landscaping restoration.
Polar Deserts
Arctic soils in polar deserts are unique. The soil receives 15 to 26 cm of rain each year, and plants thrive in some places (when the temperature allows). Polar desert soil has no soil horizons and no surface humus. You will also find that most polar soils are actually frozen.
Polar desert soils are found around the Earth’s North and South Pole. The frozen soil there can preserve anything that gets caught inside before freezing. This type of soil does not unfreeze as it is permafrost.
Organisms in the Desert
Many desert organisms make their home in the hot sands of deserts. You may have heard about snakes, camels, and cactus plants, but have you heard about these other organisms in the desert?
Desert Plants
- Barrel Cactus
- Brittlebush
- Desert ironwood
- Creosote bush
Desert Reptiles
- Horned lizard
- Chuckwalla
- Gila monster
- Tortoise
Desert Birds
- Cactus wren
- Gambel’s Quail
- Phainopepla
- Verdin
Desert Mammals
- Kangaroo Rat
- Coyote
- Hare
- Bighorn Sheep
Deserts Around the World
Deserts in the USA are not the only deserts in the world. In fact, there are many deserts in other countries that are far larger. For example, the Sahara Desert, which takes up 3.552 million square miles, is located in Northern Africa. The Sahara Desert has some grassland, but the majority of its soil is aridisols, which are dry and hot.
Here are some other deserts, in and out of the USA.
Death Valley, California
Typic Torrifluvent (hot and dry soil / subtropical)
Monument Valley, Arizona
Red Soil
Erg Chebbi (Merzouga Desert) in Morocco
Entisols Soils
Frequently Ask Questions – Desert Soil
Where is desert soil found?
Desert soil occurs in areas of the world that have very little rainfall or an abundance of sand. Desert soils can be found in subtropical states of the USA, such as Florida, in drier areas of the middle eastern countries, or any major desert of the world.
How many deserts are in the world?
There are at least 27 deserts in the world. However, as years pass, this number can change because of fluctuations in the environment and the effects of climate change. Click here to view a list of deserts in the world.
What makes desert soil infertile?
Desert soil has at least 90% of sand as its composition. Other types of soil have more clay and silt, which are better for allowing plants to thrive. Desert soil is also usually located in dry climates, and so, organic materials are not present to fertilize the soil in the first place.
Why are desert soils low in organic matter?
Desert soil does not provide adequate nutrients and sustainability for plants and animals, which means they are most likely to decompose over another type of soil, and the desert soil misses out on the creation of organic matter.
Read Next: