Question

The passive factors of soil formations are _________ and _________

• A. Time and Relief
• B. Climate and Organisms
• C. Time and Organisms
• D. Parent materials and Organisms

Hint:

To remember this division, think of active factors as the 'energizers' (Climate and Organisms), while passive factors represent the 'structural canvas' (Parent Material, Relief, and Time) on which they work.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
According to Jenny's fundamental equation of soil formation, soil is a function of five key soil-forming factors:
\[ S = f(Cl, O, R, P, T) \]
where $Cl$ is climate, $O$ is organisms (biosphere), $R$ is relief (topography), $P$ is parent material, and $T$ is time.
These factors are divided into active factors and passive factors.

Step 2: Detailed Explanation:
Let us classify these soil-forming factors:
1. Active Factors: These are the factors that directly provide energy and mass for soil development.
- Climate (temperature and precipitation) drives weathering and chemical reactions.
- Organisms (vegetation, soil microbes, fauna, and human activities) supply organic matter and cycle nutrients.
2. Passive Factors: These are the factors that are acted upon by the active factors. They provide the physical template, chemical composition, and duration for soil development.
- Parent Material determines the initial mineral composition and texture of the soil.
- Relief (Topography) affects water runoff, erosion rates, and temperature profiles based on slope and aspect.
- Time determines how long the active factors have been weathering the parent material.
Therefore, among the options provided, "Time and Relief" are passive soil-forming factors.

Step 3: Final Answer:
The passive factors of soil formation are Time and Relief, corresponding to option (A).