A livestock farmer plans to divide a large grazing area into four paddocks for rotational grazing. Fig. 3 shows the planned layout with gates at positions m...

Labelled answer diagram:

(a) Two types of fence post [2]

Any two from:

• Corner post / strainer post [1] - the heavy, deeply set post placed at each corner or end of the fence line.
• Intermediate post / line post [1] - the lighter posts placed at regular intervals along the fence line between strainers.
• Dropper / stay [1] - a short, light post or wire stay placed between intermediate posts to keep wires spaced evenly.
• Gate post [1] - a reinforced post on either side of a gate opening.

(b) Why corner posts need deeper setting and bracing [2]

Corner posts bear the pulling force (tension) of the wire from two directions where the fence changes angle [1]. Without deep setting and bracing, this tension would pull the post inward or cause it to lean over time, loosening the entire fence line and making it ineffective [1].

(c) Steps for constructing a post-and-wire fence [5]

The construction follows a logical sequence:

1. Mark the fence line and measure the spacing for posts along the planned boundary [1].
2. Dig holes to the correct depth and set the corner posts and strainer posts first, packing the soil firmly around them or using concrete to hold them rigid [1].
3. Set intermediate posts at regular intervals along the line, typically 3 to 4 metres apart [1].
4. Attach the wire to the first strainer post and run it along the fence line, threading it through or stapling it to each intermediate post [1].
5. Use a wire strainer (tensioning tool) to pull the wire to the correct tightness so it does not sag between posts [1].

Droppers may be installed between intermediate posts for additional wire support.

(d) Two advantages of dividing grazing into paddocks [4]

Any two, each explained:

1. Rotational grazing: Dividing the area into paddocks allows the farmer to move livestock between them so that pasture in resting paddocks can recover and regrow [1]. This maintains long-term pasture productivity and prevents degradation [1].
2. Stocking rate control: Paddocks prevent overgrazing by limiting the number of animals per unit area at any one time [1]. This ensures each paddock is grazed evenly rather than some areas being overgrazed while others are underused [1].
3. Livestock management: Separate paddocks make it easier to group livestock - for example, keeping breeding stock apart from young animals [1], or isolating sick animals for treatment [1].
4. Parasite management: Moving animals away from contaminated pasture breaks parasite lifecycles [1], reducing the worm burden on the herd and improving animal health [1].

(e) Why gates are needed at positions marked G [2]

Gates at each marked position allow the farmer to move livestock between the four paddocks for rotational grazing without having to dismantle any section of fence [1]. They also allow vehicle or machinery access into each paddock for pasture maintenance, supplementary feeding, or veterinary treatment [1].