Question

Which does NOT belong to the soil order in Soil Taxonomy?

• A. Oxisols
• B. Andisols
• C. Podsols
• D. Gelisols

Hint:

Mnemonic for the 12 Soil Orders: A-A-A-E-G-H-I-M-O-S-U-V
(Alfi, Andi, Aridi, Enti, Geli, Histo, Incepti, Molli, Oxi, Spodo, Ulti, Verti).
Notice that Podzol/Podsol starts with 'P', and there is no order starting with 'P' in this list.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify which term is not a recognized "Soil Order" in the official USDA Soil Taxonomy system.
Detailed Explanation:

• USDA Soil Taxonomy Orders:
The modern US system (used globally) recognizes 12 soil orders, each ending with the suffix "-sol."
These are: Alfisols, Andisols, Aridisols, Entisols, Gelisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, and Vertisols.

• Verifying the Options:
Oxisols (A): Highly weathered tropical soils rich in Fe and Al oxides.
Andisols (B): Soils formed from volcanic ash.
Gelisols (D): Soils that have permafrost within 2 meters of the surface.

• Analysis of "Podsols" (C):
"Podzol" (or Podsol) is a traditional term from the Russian soil classification system meaning "under-ash."
In the USDA Soil Taxonomy, these acidic, leached forest soils are officially classified under the order Spodosols.
While "Podzol" is still used in international systems like the WRB (World Reference Base), it is not a "Soil Order" name within the specific framework of USDA Soil Taxonomy.

• Naming Logic:
Order names are often derived from Latin or Greek roots (e.g., Oxi- from oxide, Geli- from frost) and must strictly end in "-sols" to be considered a taxonomical order.

Step 2: Final Answer:
"Podsols" is a term for a soil type, but it is not one of the 12 Soil Orders of USDA Soil Taxonomy. The equivalent order is Spodosols.