Which of the following is NOT a soil order mentioned in the text?

Ultisol is indeed a recognized soil order, characterized by its weathered properties and typically found in humid temperate and tropical regions. This order is known for its clay-rich horizon that has undergone significant leaching, resulting in lower fertility compared to some other soil orders.

Spodic soils, on the other hand, are a specific soil type that can be found within the broader category of the Podzol soil order. They are known for having a subsurface horizon rich in illuvial organic matter, aluminum, and iron, often found in cooler, wet climates.

Mollisol refers to another distinct soil order, prevalent in grassland ecosystems. It is recognized for its thick, dark topsoil rich in organic matter, making it especially fertile and ideal for agriculture.

Inceptisol is yet another established soil order, signifying soils that have weakly developed horizons and are often found in diverse climates. They occupy a transitional position in terms of development, exhibiting features that are more advanced than Entisols, but less than other more mature soil orders.

The answer, therefore, highlights the recognition of Ultisol as an established soil order, while the question seeks to identify something that is not recognized as such.