No, desert soils are generally not considered fertile in their natural state. While they may contain certain nutrients like calcium and phosphate, they are typically deficient in crucial elements like nitrogen and organic matter. This low organic matter content is directly linked to the lack of water, which prevents the growth of diverse plant life necessary to build up fertile soil.
Why Desert Soils Lack Fertility
Several factors contribute to the infertility of desert soils:
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Low organic matter: The scarcity of water inhibits the growth of plants, meaning less organic material is decomposed and added to the soil to enrich it. As noted in Soils Protect the Natural Environment, "The driest soils, in deserts, have very little organic matter because there is not enough water to support a large or diverse plant community."
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Low nitrogen levels: Nitrogen is a vital nutrient for plant growth, but its availability in desert soils is severely limited. This is explicitly stated in multiple sources, including the ScienceDirect Topics overview on Desert Soil, which highlights a "low content of nitrogen and organic matter".
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High calcium carbonate and phosphate: While calcium and phosphate are essential nutrients, their excessively high levels in desert soils can create imbalances, hindering the uptake of other vital nutrients.
Exceptions and Nuances
It's important to note that the fertility of desert soils isn't uniform. Localized areas, often beneath the canopies of shrubs, exhibit higher fertility due to the accumulation of organic matter. These are sometimes referred to as "fertile islands". As stated in Desert Soils, "...two groups of very small animals, arthropods and nematodes, are abundant in desert soils, especially in the fertile islands beneath plant canopies." These "fertile islands" demonstrate that with the addition of organic material and moisture, desert soils can support plant life. However, this is an exception, not the rule for the desert landscape as a whole.
Furthermore, human intervention, such as irrigation and the addition of fertilizers, can dramatically improve the fertility of desert soils, allowing for agricultural production. This is supported by sources such as How The Desert Soil Can Become Fertile, which mentions that scientists have transformed desert sand into highly nutritious soil.
Conclusion
While desert soils can be improved with water and other inputs to become productive, in their natural state, they are generally infertile due to low organic matter, nitrogen deficiency, and nutrient imbalances.
