Question

Specific draft of a tillage implement is defined as

• A. Horizontal component of the Pull
• B. Vertical component of the Pull
• C. Draft of the implement per unit cross sectional area of the furrow slice cut by the tillage tool of the implement
• D. Draft of the implement in a specific soil condition.

Hint:

Draft = Total horizontal force (N).
Specific Draft = $\frac{\text{Draft}}{\text{Width} \times \text{Depth}}$ ($\text{N/m}^2$).
Unit: $\text{N/cm}^2$ or $\text{kPa}$.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Specific draft (or unit draft) is a standardized parameter indicating the soil resistance encountered per unit furrow cross section.
Key Formula or Approach:
\[ \text{Specific Draft } (D_s) = \frac{\text{Total Draft } (D)}{\text{Width of cut } (w) \times \text{Depth of cut } (d)} \]
expressed in \(\text{N/cm}^2\), \(\text{kN/m}^2\), or \(\text{kg/cm}^2\).

Step 2: Detailed Explanation:
Draft is the horizontal component of total pull in the direction of tractor motion.
Because total draft increases with larger cutting widths and depths, implements are compared using specific draft:
\[ \text{Specific Draft} = \frac{\text{Draft}}{\text{Furrow Cross-sectional Area}} = \frac{D}{w \cdot d} \]
This allows normalized comparison across different plough sizes and tillage depths.

Step 3: Final Answer:
Thus, specific draft is the draft per unit cross-sectional area of the furrow slice, matching option (C).