Question

Effective root zone depth of rice, wheat, maize and sugarcane are in the sequence of:

• A. Rice < Wheat < Maize < Sugarcane
• B. Wheat < Rice < Maize < Sugarcane
• C. Maize < Rice < Wheat < Sugarcane
• D. Sugarcane < Maize < Wheat < Rice

Hint:

Matching irrigation depth to the effective root zone depth prevents deep percolation losses and saves water, especially for shallow-rooted crops like rice.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The effective root zone depth is the soil depth from which a crop extracts the majority of its water and nutrients.
It determines the capacity of the soil moisture reservoir and is a key parameter for scheduling the depth of irrigation water to apply.

Step 2: Detailed Explanation:
Let us compare the root system profiles of the given crops:
1.Rice: Rice is cultivated under submerged, anaerobic soil conditions, which restricts deep root development.
It has a shallow fibrous root system, with an effective root zone depth of only \( 30\text{ cm} \) to \( 60\text{ cm} \).
2.Wheat: Wheat is a moderately deep-rooted cereal crop grown under upland, well-drained conditions.
Its effective root zone depth typically ranges from \( 90\text{ cm} \) to \( 120\text{ cm} \).
3.Maize: Maize has a robust, extensive fibrous root system that can penetrate deeper than wheat.
Its effective root zone depth is about \( 100\text{ cm} \) to \( 135\text{ cm} \).
4.Sugarcane: Sugarcane is a tall, heavy-stemmed perennial crop with a deep, extensive root system.
Its effective root zone depth is the deepest among the four, ranging from \( 120\text{ cm} \) to \( 180\text{ cm} \).
Arranging these in ascending order:
\[ \text{Rice } (30\text{-}60\text{ cm}) < \text{ Wheat } (90\text{-}120\text{ cm}) < \text{ Maize } (100\text{-}135\text{ cm}) < \text{ Sugarcane } (120\text{-}180\text{ cm}) \]

Step 3: Final Answer:
The effective root zone depths follow the ascending sequence of Rice < Wheat < Maize < Sugarcane.