Question

The micro-organisms responsible for maximum nutrient cycling in the soil are

• A. Bacteria
• B. Actinomycetes
• C. Fungi
• D. Algae

Hint:

Bacteria are the most abundant in number and metabolic speed, making them the primary drivers of rapid soil chemical transformations.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Soil microbes are critical drivers of biochemical transformations, including nitrogen fixation, mineralization, nitrification, and organic matter decomposition.

Step 2: Detailed Explanation:
Let us compare the roles of the listed microorganisms:
Bacteria are the most numerous and metabolically diverse group of microorganisms in agricultural soils.
They have extremely rapid replication rates and are responsible for the vast majority of biochemical cycles (such as Nitrogen, Phosphorus, and Sulfur cycles).
Examples include Rhizobium (Nitrogen fixation), Nitrosomonas (Nitrification), and phosphorus-solubilizing bacteria (PSB).
Fungi are vital for breaking down complex organic molecules like lignin and cellulose, but their turnover is slower.
Actinomycetes are important for organic matter decomposition and soil aroma, but operate at a lower metabolic rate than bacteria.
Algae are primary producers on the soil surface but contribute minimally to subsurface nutrient cycling.
Therefore, bacteria are responsible for the maximum nutrient cycling rate in soil.

Step 3: Final Answer:
Bacteria are the microorganisms responsible for maximum nutrient cycling in the soil.