Question

The comprehensive system of soil classification is based on

• A. Soil colour and vegetation
• B. Soil environmental factors
• C. Measurable soil properties
• D. Intrinsic properties of soil

Hint:

Modern Soil Taxonomy uses precise "diagnostic horizons" (like mollic, argillic, or spodic) defined by quantitative limits of organic carbon, clay content, and base saturation.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Modern soil taxonomy (such as the USDA Comprehensive System of Soil Classification) is designed to be an objective, scientific framework. It categorizes soils based on observable and quantitative criteria rather than inferred origins.

Step 2: Detailed Explanation:
- Older classification systems were often genetic, meaning they grouped soils based on assumed environmental factors, climate, or parent material.
- The modern comprehensive system (USDA Soil Taxonomy) is based on measurable soil properties (including diagnostic surface and subsurface horizons, soil moisture, and temperature regimes).
- This quantitative approach allows different soil scientists to independently class the same soil using measurable field and laboratory data.

Step 3: Final Answer:
The comprehensive system of soil classification is based on measurable soil properties.