Subtopic: Type, selection, maintenance and repair of tractors and power tillers
Question Statement:
Which of the following operational distinctions describe forward-rotation (down-cut) versus reverse-rotation (up-cut) rotary tillers used with tractors and power tillers?
Options:
(A) Forward-rotation rotavating creates a forward pushing thrust on the tractor, helping reduce drawbar wheel slip in soft ground
(B) Reverse-rotation rotavating pulls soil upwards and cuts against firm soil, providing deeper penetration and finer seedbed tilth
(C) Reverse-rotation tilling requires a significantly higher holding tractive draft from the tractor to prevent the tiller from running away
(D) Reverse-rotation rotavating consumes less PTO power than forward rotation for the same depth of cut
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
- **A is correct:** Down-cut blades push the chassis forward, reducing wheel slip.
- **B is correct:** Up-cut blades cut from the bottom up against unworked ground, avoiding soil compression.
- **C is correct:** The rotor exerts a heavy backward drag force, requiring high tractor wheel traction to prevent forward stalling.
- **D is incorrect:** Up-cut rotavating consumes roughly $10\text{--}20\%$ MORE PTO power due to deeper bite and greater soil throwing against the rear shield.