Question

While sowing mustard seeds (bulk density = 800 kg.m\(^{-3}\)), a four-row fluted roller type seed drill with 25 cm row spacing operates at a speed of 2.5 km.h\(^{-1}\). For a desired seed rate of 5.0 kg.ha\(^{-1}\), the flowrate of seeds from the machine in m\(^3\).h\(^{-1}\) is:

• A. \( 0.391 \times 10^{-3} \)
• B. \( 1.172 \times 10^{-3} \)
• C. \( 1.563 \times 10^{-3} \)
• D. \( 1.953 \times 10^{-3} \)

Hint:

To calculate the flowrate of seeds, remember to convert speed to the appropriate units and use the bulk density to relate mass and volume.

Answer 1

The Correct Option is C

To calculate the flowrate of seeds, we use the formula:

Flowrate (m³·h⁻¹) = (Seed rate (kg·ha⁻¹) / Bulk density (kg·m⁻³)) × Area per hour (ha·h⁻¹)

Step 1: Calculate the area sown per hour
Area per hour = Speed × Row spacing × Number of rows

Convert speed from km/h to m/h:
2.5 km/h = 2500 m/h

Thus, the area per hour is:
2500 m/h × 0.25 m × 4 = 2500 m²/h = 0.25 ha·h⁻¹

Step 2: Calculate the flowrate
Flowrate = (5.0 kg·ha⁻¹ / 800 kg·m⁻³) × 0.25 ha·h⁻¹
= 1.563 × 10⁻³ m³·h⁻¹

Thus, the flowrate of seeds from the machine is 1.563 × 10⁻³ m³·h⁻¹.