Irrigation method Water applied per hectare (litres) Labour needed Initial cost Flood (basin) 12 000 Low Low Furrow 9 000 Medium Low Sprinkler 6 500 Low Hig...

(a) Flood (basin) irrigation requires the most water per hectare at 12,000 litres [1]. This is because the entire field surface is covered with water, leading to high losses through evaporation and deep percolation.

(b) Two advantages of drip irrigation compared to flood irrigation:

1. Drip irrigation uses significantly less water (4,000 vs 12,000 litres per hectare), making it far more water-efficient [1].
2. Water is delivered directly to the root zone of each plant, so less water is lost through evaporation from the soil surface [1].

Other acceptable advantages: less risk of waterlogging, reduced weed growth between crop rows (since only the area near each plant is wetted).

(c) A farmer with a large wheat field might choose sprinkler irrigation rather than drip irrigation because sprinkler systems have a lower initial cost than drip systems [1]. Drip irrigation requires a lateral line and individual emitter for each plant, which becomes extremely expensive over a large field; sprinklers can cover the same area with fewer, less costly components [1].

(d) How furrow irrigation works:

1. Channels (furrows) are dug between the rows of crops across the field [1].
2. Water is released into the furrows from a supply channel, pipe, or siphon at the head of the field [1].
3. Water flows along the furrows by gravity and soaks laterally into the soil from the sides of each furrow, reaching the crop roots in the raised beds between furrows [1].

(e) For a farmer with a small plot of tomatoes and a limited water supply, drip irrigation would be best [1]. It uses the least amount of water per hectare (4,000 litres) and delivers water directly to each plant, minimising waste through evaporation or runoff [1]. Although the initial cost is high, on a small plot the total investment is manageable, and the water savings are critical when supply is limited.