Liming strategies pay off and pass the acid test

The West Australian
GRDC western regional panel member Susan Hall.
Camera IconGRDC western regional panel member Susan Hall. Credit: Countryman

Growers have been busy in recent weeks applying lime to paddocks as part of ongoing efforts to overcome soil acidity and maximise farming potential.

Lime's importance in improving soil pH levels is highlighted by the latest Department of Agriculture and Food estimates that show soil acidity costs WA growers up to $500 million per year in lost production.

But getting the best value from their lime investment is a high priority for growers.

According to Grains Research and Development Corporation western regional panel member Susan Hall, there is no doubt lime can improve yields on acidic soils.

"Results from GRDC-supported research conducted by DAFWA and CSIRO reveal lime application increases medium to long-term yields by an average of 0.25 tonnes/ha, or 12 per cent," she said.

"But lime takes time to react in the soil and significant yield responses in the first two years after application are not usually achieved."

Ms Hall said the GRDC was investing in research looking at the interaction of soil pH with nutrient availability.

This includes recent trials, led by Department of Agriculture and Food WA's Craig Scanlan, investigating how cultivation and lime change soil nutrient availability. Dr Scanlan found a quicker "payback" on lime application was possible using incorporation, although the yield benefit was mostly because of the cultivation effect.

Trials at Dandaragan and Dalwallinu showed the yield benefit achieved by cultivation alone was enough to offset, in the first year of application, the cost of cultivation and some lime application.

Dr Scanlan said the trials found investment in fertiliser did not need to be cut to achieve a profit from lime incorporation.

He believes the incorporation of lime using cultivation will have ongoing benefits.

Agribusiness Crop Updates papers about lime and soil acidity are available at www.giwa.org.au/2014-crop-updates .

Meanwhile, a GRDC-supported trial hosted by the West Midlands Group tested a range of tillage treatments to incorporate lime.

The researchers last year found only deep tillage techniques were likely to incorporate lime into the 20cm to 30cm acidic layer and it was important to understand the depth to which lime needed to be incorporated and which subsoil layers needed correction.

More information about lime can be found at www.agric.wa.gov.au/climate-land-water/soils/soil-con straints/soil-acidity, or www.lime wa.com.au, which can be used with the www.soilquality.org.au online lime comparison calculator.

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