Question

The minimum satisfactory value of uniformity coefficient under normal condition of pressure and wind velocity in spinkler is

• A. 75% - 80%
• B. 80% - 85%
• C. 85% - 90%
• D. 90% - 95%

Hint:

Christiansen's Uniformity Coefficient is calculated as:
\( C_u = 100 \left( 1 - \frac{\sum |x - \bar{x}|}{n \cdot \bar{x}} \right) \).
An acceptable agricultural standard is \( C_u \ge 85\% \).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The uniformity coefficient (specifically Christiansen's Uniformity Coefficient, $C_u$) is a statistical index used to evaluate the uniformity of water distribution from a sprinkler system over an irrigated area.
Detailed Explanation:
- Christiansen's Uniformity Coefficient is calculated based on catch-can measurements placed in a grid pattern.
- A higher $C_u$ value indicates that all parts of the field receive nearly equal depths of water.
- Under normal operating conditions (including standard pressures and low-to-moderate wind velocities), a uniformity coefficient of ______80% to 85%______ is considered the minimum acceptable standard for a well-designed agricultural sprinkler system.
- If $C_u$ falls below 80%, some areas of the field will be significantly under-irrigated while others are over-irrigated, leading to uneven crop growth and water waste.
- For high-value or closely spaced crops, a higher uniformity (above 85%) may be required.

Step 2: Final Answer:
The minimum satisfactory value for the uniformity coefficient of a sprinkler is 80% - 85%, corresponding to option (B).