5 A cotton farmer plans to apply a foliar fungicide to control leaf spot disease. The recommended application rate on the label is 2.0 kg of product per hec...

(a) The total mass of fungicide product needed:

\[ \text{Total mass} = 2.0 \;\text{kg/ha} \times 3.5 \;\text{ha} = 7.0 \;\text{kg} \] [1] for the correct multiplication, [1] for the answer 7.0 kg. [2]

(b) First convert the total mass to grams:

\[ 7.0 \;\text{kg} \times 1000 = 7000 \;\text{g} \] [1]

The label states 4 g per litre of water, so:

\[ \text{Volume of water} = \frac{7000 \;\text{g}}{4 \;\text{g/L}} = 1750 \;\text{litres} \] [1] for the correct division, [1] for the answer 1750 litres. [3]

(c) The correct mixing and loading procedure (any four steps): [4]

1. Read the product label for mixing instructions, dosage and safety information before opening the container. [1]
2. Put on protective clothing (rubber gloves, face mask or respirator, overalls, rubber boots) before handling the chemical. [1]
3. Measure the correct amount of product using a dedicated measuring container. [1]
4. Half-fill the sprayer tank with clean water, add the measured fungicide product, then top up to the required volume while agitating or stirring to ensure an even mixture. Rinse the measuring container into the tank so no product is wasted. [1]

(d) Two environmental risks of applying fungicide near a stream (any two): [2]

1. The fungicide could contaminate the stream water through spray drift or surface runoff, harming aquatic organisms such as fish, frogs and aquatic insects. [1]
2. The chemical could enter the aquatic food chain, accumulating in organisms and affecting animals further up the chain, or downstream users could drink or use the contaminated water for irrigation. [1]

(e) One way to reduce the risk (any one): Leave an unsprayed buffer zone or vegetation strip along the stream bank. [1] This physical barrier intercepts spray drift and filters chemical-laden runoff before it reaches the water. (Alternatives: spray only when wind direction is away from the stream; do not wash spraying equipment near the stream; use a hooded or shielded nozzle to reduce drift.)

(f) Calibration ensures that the sprayer delivers the correct volume of spray per hectare, matching the recommended application rate on the label. [1] If too little spray is delivered per hectare, the fungicide is under-applied and the disease is not adequately controlled, wasting the cost of the application. [1] If too much spray is delivered, chemical is wasted, costs increase, and there is a greater risk of crop damage (phytotoxicity) and environmental contamination, or the residue may exceed the maximum residue limit (MRL). [1]