Combatting weeds in the grove
By Laura Thomas
Above average rainfall is predicted for much of mainland Australia over the coming months, as soaking rains begin to provide drought relief for farmers.
The Bureau of Meteorology has released its long-range forecast for August-October, revealing a 60% to < 80% chance of above-average rainfall for most parts of the country.
This is good news for olive growers and farmers everywhere.
But with decent rain beginning to fall, it’s not only the olive trees that will flourish – so too will the weeds.
Weed control is vital for optimal olive tree health and productivity, but besides chemical sprays and regular slashing and mowing, what can be done about it?
Here’s some preventative control measures to help you spend less time removing weeds and more time doing what you do best – producing delicious Australian-grown olives!
Cover crops
Inter-row cover crops provide an environmentally friendly weed competition option.
Having a ground cover such as a cover crop or mulch – as opposed to just bare earth, which can result from spraying a non-selective herbicide – will help keep weeds down naturally.
They can also help prevent erosion, improve soil fertility and increase water absorption.
Using a nitrogen-producing crop such as legumes, barley or rye will help increase nitrogen in the soil, correcting this common nutrient deficiency and reducing the frequency of fertiliser application required.
Click here to find out more about cover crops and recent trials undertake by Soil Wealth ICP.
Mulching
A layer of mulch provides a barrier between the soil and the sun, helping to keep weed growth to a minimum.
Organic mulch made from olive tree prunings and other plant material is a great way to make use of a waste product, tidy up the grove and prevent weed growth all at the same time.
Layer it throughout the grove – being sure to keep clear of the base of the trees – and replenish as required as it breaks down naturally.
Take a look back at our Olivegrower and Processor article from September 2015, to see how one Australian grower was able to use olive cuttings to improve the health of both soil and trees alike.
Grazing
Strategic animal grazing is another great way to remove weeds.
Sheep are the perfect, environmentally friendly lawnmower for your grove, keeping weeds down and fertilising the soil all at once.
They also make a great fire risk reduction strategy for Australia’s bushfire-prone summers, by removing dry fuel from the ground.
Just remember to keep an eye on feed levels to avoid your flock causing unwanted damage to tree bark, low-hanging branches and foliage.
Sheep must also be moved out of the grove well in advance of harvest to eliminate the risk of faecal contamination of olive crops.
Chemical spraying
Of course herbicide is a common weed management strategy used by Australian olive growers – and farmers – across the country.
While an integrated pest and disease management best practice approach is always recommended, most growers use some form of chemical application.
It’s important you ensure the chemicals you use are approved for use in olive groves and understand any withholding periods that may apply.
The Australian Government’s agvet chemical regulator, the Agricultural Pesticides and Veterinary Medicines Authority (APVMA), has approved a range of chemicals for use on olive trees.
A full list can be found via the APVMA’s online permit register, here.
You can also take another read of our previous article Spraying for weeds, bugs and disease – understanding the chemicals you use, available on the AOA website.
More information:
A wealth of information is available for members on the Australian Olive Association website.
The AOA’s Yearly Orchard Planner is another handy tool for members, accessible via the website.
Not a member? Come and join us!
Find out more about the benefits of joining the industry’s national representative body.
Sources:
https://australianolives.com.au/
https://www.apvma.gov.au/
http://www.bom.gov.au/
Australian and New Zealand Olivegrower and Processor