Module 4:

Materials

4.4 How much is needed?

4.4.5 Pesticide: Weedkiller (Herbicide)

A herbicide has an application rate of 2-litres of concentrate per hectare.

If this is to be included in a 300-litre sprayer tank there would be 298 litres of water as well as the 2 litres of concentrate to be sprayed on 1 hectare (10,000m²) of turf.

If a football pitch is 7000m² in total area, how much of this mixture would be needed?

1. Do you need some initial help with the calculations?

The size of the football pitch is somewhat smaller than one hectare, so the answer has to be less than 300 litres.

What is the size of the football pitch as a percentage of a hectare?

2. Do you need some more help with the final calculation?

If the football pitch is 7,000m² and one hectare is 10,000m², then the size of the football pitch as a percentage of a hectare is 70%.

7,000 ÷ 10,000 = 0.7 x 100 = 70%

Can you now work out the total quantity that is required?

3. Do you need some other help with the final calculation?

If 300 litres is required for 1-hectare and the football pitch is just 70% (which is represented as 0.7) of this area then 300 x 0.7 = 210 litres.

There can be another way to arrive at a correct answer, but hopefully the above approach has been clear

1 Not all pitches will require the application of a herbicide, whilst others may have one or usually no more than two (only if the product allows this) applications in a year. 5-litre containers are common for these products.

2 An example of a selective herbicide (with the active ingredient being 2,4-D) for the control of weeds in managed turf is Depitox 500 (April 2025). This has an application rate of 2.8 litres (of concentrate) per hectare (diluted with 100 - 1,000 litres of water) for most common weeds, including creeping buttercup, plantains, daisy, dandelion and yarrow; clovers will receive a check in growth rather than good control. A maximum of 3 applications per year are also permitted with this chemical. For a pitch of 7,000m², this would then use 1.96 litres of concentrate per application.

Module progress: 77%

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