Which climatic factors have the most significant impact on decomposition?

Temperature and soil moisture

The correct answer is a) Temperature and soil moisture.

Temperature and soil moisture are the climatic factors that have the most significant impact on decomposition. These factors directly influence the activity and effectiveness of soil microorganisms responsible for decomposition processes.

1. Temperature: Decomposition rates are strongly influenced by temperature. Warmer temperatures generally promote faster decomposition, while lower temperatures slow down the process. This is because higher temperatures increase the metabolic activity of soil microorganisms, allowing them to break down organic matter more efficiently. In contrast, colder temperatures limit microbial activity and reduce decomposition rates.
2. Soil Moisture: Adequate soil moisture is essential for decomposition to occur. Moisture provides the necessary environment for microbial activity and enzymatic reactions involved in decomposition. It facilitates the transport of dissolved substances and the diffusion of enzymes, allowing microorganisms to access and break down organic matter effectively. However, excessive moisture can lead to anaerobic conditions, limiting oxygen availability and slowing down decomposition.

While oxygen levels (option b), sunlight exposure (option b), wind speed (option c), rainfall (option c), humidity (option d), and atmospheric pressure (option d) can indirectly affect decomposition by influencing soil moisture and temperature, temperature and soil moisture are the primary factors that directly impact decomposition rates.