Fig. 1 shows a disc harrow used in seedbed preparation. (a) Name the parts labelled A and B on the diagram. [2] (b) Describe the function of a disc harrow w...

Labelled answer diagram:

(a) The labelled parts of the disc harrow are:

• A - Disc (blade) [1]. These are concave, circular steel cutting discs that rotate as the harrow is pulled across the field.
• B - Frame (toolbar) [1]. The rigid metal frame holds the disc gangs in position and connects the implement to the tractor's three-point linkage.

(b) The function of a disc harrow when preparing a seedbed:

1. It cuts and turns over the soil surface, incorporating crop stubble and residues [1].
2. It breaks up large soil clods into smaller pieces, creating a finer tilth suitable for seed placement and germination [1].
3. It mixes crop residues and organic matter into the soil, which improves soil structure and promotes decomposition [1].

The disc harrow is typically used as a secondary tillage implement after primary ploughing, to refine the seedbed before planting.

(c) Two safety precautions when operating a disc harrow (any two) [2]:

• Ensure all bystanders and workers are clear of the implement before starting, as the rotating discs can cause serious injury [1].
• Check that all discs are securely fastened to the frame before use, to prevent a disc detaching during operation [1].

Other valid precautions: do not stand behind the harrow when it is in motion; wear protective footwear and clothing.