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: Decomposition rates depend on the composition of organic matter in the soil. Sugar decomposes the fastest, followed by chitin, and lignin decomposes the slowest. Nitrogen content also enhances microbial activity, speeding up decomposition.
Step 2: Soil A has 40% lignin (slow to decompose), 0% sugar (fast to decompose), 45% chitin, and 5% nitrogen. The high lignin and low nitrogen suggest a slower decomposition rate.
Step 3: Soil B has 5% lignin, 35% sugar (fast to decompose), 15% chitin, and 45% nitrogen. The high sugar and nitrogen content indicate a faster decomposition rate.
Step 4: Comparing the two, Soil A, with more lignin and less sugar/nitrogen, will decompose more slowly than Soil B, which has more sugar and nitrogen to support faster microbial activity.
Thus, Soil A has a slower rate of decomposition than Soil B.