Question

Given below are five statements about soil pH:

(A) Majority of red soils are loams with pH values ranging between 5.0 to 8.0.

(B) Laterite soils, which are generally acidic, have an average pH range between 6.0 to 7.0.

(C) Red and yellow soils have a pH around neutrality or else slightly on the acidic side.

(D) Desert soils have a fairly high pH and varying amounts of calcium carbonate.

(E) Alkali soils have a high pH which may range between 7.0 and 8.0.

Choose the correct answer from the options given below:

• A. (A), (C) and (D) only.
• B. (A), (B) and (C) only.
• C. (C), (D) and (E) only.
• D. (B), (C) and (D) only.

Hint:

Recall the typical pH band associated with red, laterite, desert and alkali soils.

Answer 1

The Correct Option is A

Step 1: Recall the typical pH range of each soil type from soil science, then compare it with what each statement claims.

Step 2: Statement (A) is correct. Red soils in India are largely loamy in texture and their pH commonly falls in the range of about 5.0 to 8.0, spanning mildly acidic to mildly alkaline.

Step 3: Statement (B) is false. Laterite soils are strongly leached and are known to be quite acidic, typically with pH well below 6.0, often around 4.5 to 5.5. Calling their range 6.0 to 7.0, which is almost neutral, does not match how acidic they really are.

Step 4: Statement (C) is correct. Red and yellow soils generally sit close to neutral pH or slightly acidic, which is the standard description used for these soils.

Step 5: Statement (D) is correct. Desert soils are typically alkaline with a fairly high pH, and they often contain notable and variable amounts of calcium carbonate as nodules or coatings.

Step 6: Statement (E) is false. Alkali (sodic) soils are marked by a distinctly high pH, usually above 8.5 and sometimes reaching 10 or more, not the mild 7.0 to 8.0 range given in the statement.

Step 7: The correct statements are (A), (C) and (D), matching option 1.