Question

Mohit performed an analysis of two different soil samples from two areas A and B. He recorded these results:
Soil Sample A: Lignin 40%, Sugar 0%, Chitin 45%, Nitrogen 5%
Soil Sample B: Lignin 5%, Sugar 35%, Chitin 15%, Nitrogen 45%
Which of these is true about their rate of decomposition in both the soil?

• A. Soil A has a slower rate of decomposition than Soil B.
• B. Soil A has a faster rate of decomposition than Soil B.
• C. Both have the same rate of decomposition.
• D. No decomposition occurs in A and B.

Hint:

In soil decomposition, high sugar and nitrogen content accelerate microbial activity, while high lignin content slows down the process.

Answer 1

The Correct Option is A

Step 1: Organic matter composition dictates decomposition rates. Sugars decompose most rapidly, followed by chitin, with lignin decomposing slowest. Elevated nitrogen content also boosts microbial activity, accelerating decomposition.
Step 2: Soil A contains 40% lignin (slow decomposition), 0% sugar (rapid decomposition), 45% chitin, and 5% nitrogen. The high lignin percentage and low nitrogen content suggest a slower decomposition rate.
Step 3: Soil B comprises 5% lignin, 35% sugar (rapid decomposition), 15% chitin, and 45% nitrogen. The substantial sugar and nitrogen levels indicate a faster decomposition rate.
Step 4: In comparison, Soil A, possessing higher lignin and lower sugar/nitrogen levels, will exhibit a slower decomposition rate than Soil B, which benefits from increased sugar and nitrogen to support enhanced microbial activity.
Consequently, Soil A demonstrates a slower decomposition rate than Soil B.