Crop competition

Optimise crop growth

We don’t want to give the weeds a free kick by growing un-competitive crops. Crop competition with weeds is a double-edged sword. There is the effect of the weeds on the crop, and the effect of the crop on the weeds. A competitive crop will suffer less yield loss at the hands of the weeds, and will also reduce seed set of the weeds compared to an un-competitive crop. In other words more crop, fewer weeds.

There are six main aspects of crop competition:

Higher seeding rate
Narrow row spacing
Orientation of crop – a crop sown east – west will give your crop enough sunlight, and shade the furrows to starve weeds of sunlight
Vigorous crop traits
Soil health – give your crop the best chance by having healthy soil
Time of sowing – early sowing is usually best

It’s hard to get all of the six points above right, and growers need not aspire to practise all six of these competition factors, but they can use a range of these practices to ensure that their crops have a fighting chance against the weeds.

The checklist:

Adopt at least one competitive strategy, but two is better.
Target higher plant populations using increased seeding rates, weed-free seed tested for germination, vigour and 1,000 seed weight.
Aim for even seed distribution and establishment.
Sow competitive crop types and varieties.
Improve soil health (fertility and structure) and crop nutrition, e.g., soil amelioration (if necessary), no-till, stubble retention, nutrient budgeting.
Utilise early sowing and adopt East/West sowing if practical.
Reduce row spacing where possible.

You can learn more about crop competition in our free online course, Crop Competition 101.

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Edwards family, Port Broughton SA

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