Nutrient Cycling

To solve the question, let's analyze each statement in relation to decomposition:

(A) Decomposition is an anaerobic process.
This statement is incorrect. Decomposition generally involves both aerobic and anaerobic processes. Aerobic decomposition is more common, occurring in the presence of oxygen.

(B) Decomposition rate of detritus depends upon the chemical nature of it.
This statement is correct. The rate at which decomposition occurs is influenced by the chemical composition of the detritus, such as the carbon to nitrogen ratio and the presence of complex substances like lignin.

(C) Water-soluble organic nutrients go into the soil and get precipitated in the process of leaching.
This statement is incorrect. During leaching, water-soluble nutrients are usually washed away, not precipitated.

(D) Humification follows mineralisation.
This statement is correct. Humification is the process of formation of humus, and it occurs after mineralization, where organic matter is broken down into simpler inorganic substances.

Based on the analysis, the correct statements are (B) and (D). Therefore, the correct answer is: (B) and (D) only

Mineralization is a key process in the nutrient cycle wherein microorganisms break down organic matter, specifically detritus. Detritus includes plant and animal remains or other non-living organic materials. During mineralization, microorganisms decompose this material, converting it into simpler inorganic substances. These inorganic nutrients are then released into the soil, which can be readily absorbed by plants.

In addition to mineralization, humification also occurs, where some of the decomposed organic matter is transformed into humus, a stable form of organic matter beneficial to soil structure and fertility.

Given the options, we focus on mineralization results:

• "Inorganic nutrients from detritus and formation of humus" correctly describes the process by which inorganic nutrients are released during microbial decomposition, contributing to the nutrient pool and the formation of humus.
• The other options either incorrectly emphasize the types of nutrients released or omit the formation of humus.

Therefore, the correct answer is: Inorganic nutrients from detritus and formation of humus.