Question

Which one of the following is the active formers in soil development

• A. Parent Material
• B. Topography
• C. Organisms
• D. Time or Age of the soil

Hint:

Active Factors = Climate + Organisms (Think of them as the "Engine" of soil formation).
Passive Factors = Parent Material + Topography + Time (Think of them as the "Raw Materials" or "Setting").

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question requires categorizing the five soil-forming factors into "Active" and "Passive" factors and identifying the active one from the list.
Detailed Explanation:

• Active Factors of Soil Formation:
Active factors are those that supply energy and matter that act upon the mass of soil for its transformation.
The two active factors are Climate and Organisms (Biosphere).
Climate (precipitation and temperature) provides the moisture and heat necessary for chemical and physical reactions.
Organisms (plants, animals, microbes) add organic matter and physically mix the soil, driving biological weathering.

• Passive Factors of Soil Formation:
Passive factors are the conditions or materials that are acted upon by the active factors.
These include Parent Material (the starting rock), Topography (the shape of the land), and Time (the duration of the process).

• Why are they "Active"?
Organisms are active because they represent a continuous input of energy (through photosynthesis and decomposition). They change the soil's chemistry (acids) and physical structure (burrowing/roots).

• Analysis of Options:
Parent material, Topography, and Time are all "Passive." Only "Organisms" falls into the active category as defined in classical pedology (Jenny's model).

Step 2: Final Answer:
Organisms (along with Climate) are the active factors in soil development.