Question

The optimum spacing (row × plant) of hybrid cotton grown in the irrigated areas

• A. 30 × 15 cm
• B. 60 × 30 cm
• C. 90 × 45 cm
• D. 120 × 60 cm

Hint:

- Cotton Hybrids (Irrigated) \(\rightarrow\) Wide spacing (120 \(\times\) 60 cm).
- Cotton Varieties (Rainfed) \(\rightarrow\) Narrow spacing (60 \(\times\) 30 cm or 90 \(\times\) 45 cm).
Wider spacing allows the vigorous hybrid branches to spread without shading each other.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Plant spacing (crop geometry) determines how efficiently a crop utilizes solar radiation, soil moisture, and nutrients.
The optimal spacing for cotton (Gossypium hirsutum) varies depending on the cultivar type (variety vs. hybrid), soil fertility, and water availability.
Detailed Explanation:
Hybrids and irrigated conditions alter cotton growth characteristics:
- Cotton hybrids exhibit a highly vigorous, branching growth habit compared to standard varieties.
- In irrigated, fertile soils, this growth is further enhanced, resulting in larger, more spread-out plants.
- To prevent overcrowding and allow adequate sunlight to reach the lower branches, hybrids require wider spacing.
- The standard recommended spacing for hybrid cotton in irrigated fields is 120 cm between rows and 60 cm between plants (120 \(\times\) 60 cm).
- This wide spacing yields an optimal plant population of approximately 13,888 plants per hectare: \[ \text{Population} = \frac{10000 \text{ m}^2}{2 \text{ m} \times 0.6 \text{ m}} \approx 13,888 \text{ plants/ha} \] - Narrower spacing (such as 60 \(\times\) 30 cm or 90 \(\times\) 45 cm) is typically used for compact, erect varieties or under rainfed, low-fertility conditions.

Step 2: Final Answer:
The optimum spacing for hybrid cotton grown in irrigated areas is 120 \(\times\) 60 cm.