THE CLIMATE KELPIE BLOG: Diversification reduces risk in a changing environment

Posted by BCG on 14th March 2019

A trend towards lower rainfall, particularly in winter, along with more damaging frosts have become important factorin decision making for Corrigin growers, Simon Wallwork and Cindy Stevens. After observing these trends, they have shifted their focus from productivity to profitability and diversified their business to help reduce risk.  

Image 1. Simon Wallwork

Frost and rainfall trends 

Using the Bureau of Meteorology’s Climate Data Online Simon investigated climate trends for their 3,600-hectare Western Australian property and the broader region. While both winter rainfall and the timing of the autumn break are on the decline, summer rainfall appears to have improved slightly (Figure 1). The need to capture this summer rainfall is now more important than ever and was a major factor driving some of the changes Simon and Cindy have made to their business.  

Frost represents another major risk to the cropping enterpriseCSIRO research has shown that, not only have frosts become more severe in the region, but they are also more likely to occur later in the season and damage maturing crops.  More information about CSIRO’s ‘Understanding frost risk in a variable and changing climate’ project is available via a GRDC media release or the final report. 

Figure 1: Winter rainfall is declining at Corrigin, WA, while summer rainfall is on the increase. Source: Bureau of Meteorology. 

Cropping decisions

Drier conditions and the increased potential for frost have increased the level of risk in the cropping enterprise. Simon has adapted to this by reducing inputs so that, although he isn’t chasing the highest yield, he does maximise profit. He uses the three-month forecasts from both the Bureau of Meteorology and the Department of Primary Industries and Regional Development (DPIRD) to help inform his sowing decisions. In a year like 2019, when the summer rainfall was below average, he will cut back on fertiliser inputs even though 2018 was a good season. If there isn’t an early break, he’s likely to limit sowing of crops like canola and lupins that require a longer season.

Simon uses the Bureau’s short-term forecasts to help with planning the timing for operations like sowing and spraying.

In 2018 Simon and Cindy took out multi-peril crop insurance for the first time and ended up making a claim for frost that covered the cost of the premium. Simon says, “These policies have become a bit cheaper in recent years and there are more options available now. We will probably insure for frost again this year as it is our major risk.”

Simon says his agronomic choices are all about minimising risk, “We retain stubble to maximise soil moisture and use windrow burning to manage resistant weeds. While many growers are concerned about the burn escaping, I’m not too fussed if it takes out the whole paddock. There is enough evidence out there that soils with retained stubble do not absorb as much heat and are therefore more vulnerable to frost. While we do want to retain moisture, frost is the bigger risk so this trade off works for us.”

More livestock in the mix

The business was historically focused on cropping, but Simon and Cindy have increased livestock numbers over the last few years to diversify their farming operations and spread the risk. They now have 200 breeding cows and 600 breeding ewes.

Image 2. Murray Grey cattle grazing a mix of millet, forage sorghum and sweet Sudan grass.

“The livestock enterprises have produced better gross margins than cropping in the last two seasons and allow us to spread some risk with regards to frost damage. Our livestock grazing is based on early sown fodder barley crops, producing feed in early winter so our stocking rates have risen contributing to improved gross margins. When these fodder barley paddocks are sprayed as a ‘hay freeze’ operation we control weeds and conserve some moisture for the following crop phase.”

Simon plants sacrificial barley fodder crops in early April and grazes through the year before hay-freezing in September. This gives him the opportunity to control weeds and conserve moisture ahead of the next cropping season.

He has also been experimenting with different summer fodder crops sown onto chemical fallow paddocks.

Starting with 50 hectares of millet sown in 2014, Simon has also tried sorghum, sweet Sudan grass and cowpea. While the cowpea didn’t really suit his environment, the others have worked well and in 2018 he sowed 250 hectares to these summer crops. He is now planting a blended mix of species onto the chemical fallow in late September, early October. He usually favours the lower country, which retains higher moisture, enabling him to fatten livestock while capturing the summer rainfall.

Image 3. Millet sown in early October on winter chemical fallow is ready for grazing by cattle. The non-wetting soil has been limed and mouldboard ploughed.

Improving assets

The summer crops also integrate well with Simon’s mouldboard ploughing program aimed at improving the non-wetting sands. Anecdotally he’s seen a reduction in frost severity as the improved topsoils wet up more easily. By ploughing in September while soils are wet, he can get over more country and get a better job. Observing yields from adjacent paddocks, Simon has found that barley sown onto the summer millet has out-performed barley-on-barley and he attributes this to the fact that the mouldboard treatment has ameliorated the non-wetting soil, and the grazed millet has enabled recycling of nutrients and improved root pathways.

These changes have allowed Simon and Cindy to build a more resilient business that is better adapted to their changing climate. Profitability has been improved by increasing the enterprise diversity to better manage risk, and careful management of their soil and soil-water assets.

Learn more about Simon’s approach by reading his Climate Champion profile from 2014.

Simon Wallwork, 0422 803 890, swallwork@westnet.com.au