Keeping soil erosion in check

Keeping soil erosion in check


Grain
Tony Fay, Agriculture Victoria, demonstrating how soil erosion works with different sized pieces of soil.

Tony Fay, Agriculture Victoria, demonstrating how soil erosion works with different sized pieces of soil.

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Despite the benefits of no-till, soil erosion is on the rise this season, due to the ongoing drought meaning there is litle ground cover.

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THE advent of minimum tillage cropping systems in the past decade has not only been a benefit in terms of improving water use efficiency and stubble management, but it has played a major part in reducing erosion levels.

Dust monitoring data out of NSW has showed a marked drop in the levels of dust particles in the air from 2009 to 2017.

However, even the best of farming practices has its limits and the record dry conditions over the past two years have meant dust levels in the monitored areas are again at levels near those of 2009.

Agriculture Victoria recently held a day featuring visiting NSW Office of Environment and Heritage soil erosion specialist John Leys on how to best manage soil erosion.

Agriculture Victoria south west region grains manager, Tony Fay, said the best way to reduce the risk of erosion was still to maintain soil cover.

"If there is 50 per cent ground cover you should manage to keep paddocks from wind erosion damage, and on sloping ground 70pc ground cover reduces the risk of water erosion," Mr Fay said.

"Things like stock containment and avoiding cultivation over summer are big helps in minimising the risk of wind erosion come this time of year."

At harvest time, he said farmers could also make it easier in the autumn by cutting their crops a little higher.

"Leaving higher stubble increases your protection when things start to get a bit bare in the autumn."

However, he said in low rainfall environments maintaining soil cover was difficult, especially following crops that generated lower amounts of stubble, such as pulses.

"There are a number of areas where there just isn't the soil cover there."

Mr Fay said it was difficult to manage wind erosion risks in these circumstances.

"For one thing, the pattern of high wind events means there are usually strong northerlies that swing around with the cold change to the west, then to the south-west, meaning if you have your paddock ridged north-south it will blow up and down the rows with the northerly and east-west ridges will catch the easterly."

Other winds are also erratic.

"The whirly winds that we see across the landscape in autumn are actually responsible for 10pc of total wind erosion and they are not easy to predict."

However, he said in certain circumstances ridging could be useful in mitigating the level of damage, while surface roughening, to try and create clods, was also a management tool with the correct soil types.

"It is not as effective on sandier soils, but if you can create clods that don't blow it can limit the problem."

Long term management strategies, such as shelter belts, are also good for stopping wind erosion but can bring their own issues.

"There is the issue of cutting down on your productive land, but aside from that we have found shelter belts can be home to pests such as rabbits which create soil erosion problems of their own."

The incentive is clearly there for farmers to stop soil blowing.

"The dust on the soil surface is some of the most fertile soil growers have, the last thing you want to do is send it down to the neighbours in the first dust storm," Mr Fay said.

He said research had showed that for every tonne of dust that blew off the paddock, $3-4 a hectare in nutrients were removed.

The story Keeping soil erosion in check first appeared on Farm Online.

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