Question

Arrange the given important steps of decomposition in their correct order of occurrence in the breakdown of complex organic matter and explain the fourth step in the process.
\( \fbox{Catabolism}\) \(\fbox{Leaching} \fbox{Fragmentation} \fbox{Mineralisation} \fbox{Humification}\)

Hint:

Include a relevant concept, shortcut, or useful trick related to solving this type of problem. Give useful quick tips for the question. Also properly format the text in quick tip as per latex. \textbf{Quick Tip (a):} Co-evolution often involves intricate adaptations between two species where each influences the other's evolutionary trajectory. The \textit{Ophrys}-bee interaction is a prime example of mimicry driving this process. \textbf{Quick Tip (b):} Remember the sequence of decomposition by associating each step with the agents or processes involved: detritivores for fragmentation, water for leaching, microbes and enzymes for catabolism, a slow transformation into humus, and further microbial action for releasing minerals.

Answer 1

The correct order of occurrence of the important steps of decomposition of complex organic matter is: Fragmentation: Detritivores (e.g., earthworms) break down detritus into smaller particles. Leaching: Water-soluble inorganic nutrients seep down into the soil horizon and get precipitated as unavailable salts. Catabolism: Microbial enzymes degrade the simpler soluble compounds into even simpler inorganic substances. Humification: This is the process of formation of humus. Humus is a dark-colored amorphous substance that is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. It is colloidal in nature and serves as a reservoir of nutrients. Mineralisation: The further degradation of humus by some microbes releases inorganic nutrients (minerals) back into the soil. The fourth step in the process is Humification. During humification, the partially decomposed organic matter is transformed into a stable, dark-colored amorphous substance called humus. Humus is rich in lignin and cellulose derivatives and is highly resistant to microbial action, decomposing very slowly. It is colloidal in nature, meaning it has a large surface area for nutrient retention, and it plays a crucial role in soil fertility by acting as a reservoir of essential nutrients like nitrogen, phosphorus, and potassium. Humus also improves soil structure, aeration, and water-holding capacity. Correct Answer : The correct order is Fragmentation, Leaching, Catabolism, Humification, Mineralisation. The fourth step, Humification, is the formation of humus, a dark, stable, nutrient-rich substance resistant to rapid decomposition, contributing significantly to soil fertility.