Question

The process by which water-soluble inorganic nutrients present in the detritus go down into the soil horizon and turn into unavailable salts :

• A. Mineralisation
• B. Catabolism
• C. Leaching
• D. Humification

Answer 1

Answer:

C. Leaching

• Leaching is the specific biogeochemical process described, where water-soluble inorganic nutrients are washed away from the soil or detritus by percolating water.

• This process occurs primarily due to rainfall or irrigation, which carries dissolved substances downward through the soil profile into deeper layers or groundwater.

• Once these nutrients reach the deeper layers, they often precipitate as unavailable salts, making them inaccessible to the root systems of most plants.

• Leaching is a critical step in the decomposition process, which includes five major stages: Fragmentation, Leaching, Catabolism, Humification, and Mineralization.

• Fragmentation: The breakdown of detritus into smaller particles by detritivores like earthworms.

• Catabolism: The degradation of detritus by bacterial and fungal enzymes.

• Humification: The formation of dark, amorphous substances known as humus, which is highly resistant to microbial action and acts as a reservoir of nutrients.

• Mineralization: The final stage where microbes release inorganic nutrients (such as nitrogen, phosphorus, and potassium) back into the soil, completing the nutrient cycle.

• The rate of decomposition is significantly influenced by climatic factors (temperature and moisture) and the chemical composition of the detritus (e.g., lignin and chitin content slows down the process).