Question

Choose the correct sequence of soil moisture constants for a soil after a heavy rain if no further water is added.

• A. Field capacity, Available water, Permanent wilting point, Ultimate wilting point, Saturation capacity
• B. Available water, Saturation capacity, Permanent wilting point, Field capacity, Ultimate wilting point
• C. Saturation capacity, Field capacity, Permanent wilting point, Ultimate wilting point, Available water
• D. Saturation capacity, Field capacity, Available water, Permanent wilting point, Ultimate wilting point

Hint:

Moisture condition after rainfall decreases in the following order: \[ \boxed{ \text{Saturation} > \text{Field Capacity} > \text{Available Water} > \text{Permanent Wilting Point} > \text{Ultimate Wilting Point} } \]

Answer 1

The Correct Option is D

Concept: After a heavy rainfall, soil moisture gradually decreases with time because of:
• Gravitational drainage
• Evaporation
• Plant uptake Different soil moisture conditions occur sequentially as water content reduces. The important soil moisture constants are:
• Saturation capacity
• Field capacity
• Available water
• Permanent wilting point
• Ultimate wilting point These occur in a descending order of moisture content.

Step 1: Understanding Saturation Capacity. Immediately after heavy rainfall:
• All soil pores become filled with water
• Both macro-pores and micro-pores contain water This condition is known as: \[ \boxed{ \text{Saturation Capacity} } \] This is the maximum moisture condition of soil.

Step 2: Understanding Field Capacity. After some time:
• Excess gravitational water drains away
• Soil retains only useful moisture This stage is called: \[ \boxed{ \text{Field Capacity} } \] Field capacity represents optimum moisture for plant growth.

Step 3: Understanding Available Water. Plants then begin extracting moisture from the soil. The water available between: \[ \text{Field Capacity and Permanent Wilting Point} \] is known as: \[ \boxed{ \text{Available Water} } \] This moisture can be utilized by plants.

Step 4: Understanding Permanent Wilting Point. As soil dries further:
• Plants cannot recover from wilting
• Water becomes unavailable to roots This condition is called: \[ \boxed{ \text{Permanent Wilting Point} } \]

Step 5: Understanding Ultimate Wilting Point. With additional drying:
• Soil becomes extremely dry
• Practically no usable water remains This final stage is: \[ \boxed{ \text{Ultimate Wilting Point} } \]

Step 6: Writing the correct sequence. Thus the correct sequence after heavy rain is: \[ \boxed{ \text{Saturation Capacity} \rightarrow \text{Field Capacity} \rightarrow \text{Available Water} \rightarrow \text{Permanent Wilting Point} \rightarrow \text{Ultimate Wilting Point} } \]

Step 7: Comparing with options carefully. Option (A): Incorrect arrangement because saturation capacity should come first. \[ \boxed{ \text{Option (A) is incorrect} } \] Option (B): Incorrect sequence. \[ \boxed{ \text{Option (B) is incorrect} } \] Option (C): Available water should come before permanent wilting point. \[ \boxed{ \text{Option (C) is incorrect} } \] Option (D): Correct sequence. \[ \boxed{ \text{Option (D) is correct} } \] Final Conclusion: The correct order of soil moisture constants after heavy rainfall is: \[ \boxed{ \text{Saturation Capacity} \rightarrow \text{Field Capacity} \rightarrow \text{Available Water} \rightarrow \text{Permanent Wilting Point} \rightarrow \text{Ultimate Wilting Point} } \] Hence the correct answer is: \[ \boxed{ (D) } \]