Question

Which stage of rice plant consumes more water?

• A. Initial
• B. Crop development
• C. Mid season
• D. Late season

Hint:

For almost all grain crops (including rice, wheat, and maize), the mid-season stage (which includes flowering and heading) is both the period of peak water consumption and the most critical stage for water stress.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The water requirement of a crop varies significantly across its growth stages.
This requirement is governed by the crop coefficient (\( K_c \)) and the rate of evapotranspiration (\( ET_c \)).
Critical growth stages are periods when water stress can cause maximum reduction in crop yield.

Step 2: Detailed Explanation:
The life cycle of the rice plant can be divided into four general growth stages:
1. Initial Stage (Transplanting to early tillering): The plant is small, and leaf area is minimal, resulting in low water consumption.
2. Crop Development Stage (Active tillering to panicle initiation): The crop canopy grows rapidly, and water use increases progressively.
3. Mid-Season Stage (Panicle initiation, heading, flowering, and grain filling): This stage corresponds to the peak physiological activity of the rice plant.
- The crop canopy is fully developed, and transpiration rates reach their maximum.
- The crop coefficient (\( K_c \)) for rice reaches its highest value (typically \( 1.15 \text{ to } 1.20 \)) during this period.
- Water consumption is at its peak, and this is the most critical stage where water stress can lead to spikelet sterility and major yield losses.
4. Late Season Stage (Maturity and ripening): Evapotranspiration rates decline as the crop matures and the leaves begin to yellow.
Therefore, the mid-season stage is the period of highest water consumption for rice.

Step 3: Final Answer:
The mid-season stage of the rice plant consumes the most water.