Soil management helps absorb climate variability
GroundCover™ Issue: 100 | 10 Sep 2012 | Author: Robbie Mitchell
If you have ever driven from Melbourne to Brisbane or from Sydney to Adelaide during spring, chances are you caught a glimpse of one of Anthony Gordon’s wheat paddocks.
Six hours west of Sydney at the junction of the Newell Highway and the Mid-Western Highway lies West Wyalong, a former gold-rush district that has grown into the largest cereal-growing region in New South Wales.
Anthony manages Wyalong Rural Investments (WRI), a 17,000-hectare corporate cropping operation encompassing three large aggregations (10 properties) that surround West Wyalong.
“At WRI, we focus on quality-assured traceable grain systems,” Anthony says. “Our aim is to run an efficient and highly productive winter cropping program featuring malting barley (45 per cent), wheat, canola and chickpeas.
“We’re responsible for the whole operation – staff, production, reporting, administration and compliance – which means we’re meticulous about recording everything and using it to make appropriate decisions.”
West Wyalong’s predominantly loamy soils are known for their nutrients and water retention, while still allowing excess water to drain away. The region normally receives 475 to 525 millimetres of rain a year, most of it during cool winters, and is baked from December to February with average temperatures about 30°C to 33°C.
Having come through eight years of drought from 2000, Anthony and his team recognised the need to make every drop of water count. They set about improving their soil structure to allow it to absorb as much water as it can and hold it for as long as it can.
“Soil is like a sponge – it can absorb only so much,” Anthony says. “If you put weight on a sponge to compress it, you’ll notice that the sponge will lose water and won’t be able to absorb as much as it did. The same principle applies with soil, which is why in a dryland farming system you want your soils to be as porous and non-compacted as they can be.”
WRI has electromagnetically surveyed and soil tested each paddock to determine its soil type and how compacted it is. This data has helped it develop a strategy to restore soil structure, reconfigure the layout of its paddocks and work out which parts of the land are best suited for each crop.
“To improve and maintain our soil structure, we’re applying a no-till controlled-traffic system with full stubble retention. The stubble helps protect the soil from rain and runoff, and when it’s incorporated into the soil it increases porosity.”
To retain this porosity WRI has aligned all its sowing, spraying and harvesting machinery onto three-metre tramlines to limit compaction.“After we introduced our moisture-retention systems on one property, a neighbouring farmer said that in the short time that we’d adopted these systems he was getting nowhere near the amount of runoff that he used to receive into his adjoining dams. Instances like this put a smile on your face as you know your water is staying on your land.”
Fixed soil-moisture monitors continually feed soil-moisture and weather data back to the WRI office in Forbes. But Anthony likes his agronomists to still get their hands dirty and carry out manual soil moisture tests with handheld penetrometers.
“It’s about validating the data we’re receiving from our fixed monitors as well as getting a clearer picture of how the whole paddock is functioning,” Anthony says.
Data is king for Anthony and his team. They are constantly out in the field measuring how much moisture and nutrients are in their soils, measuring the crop and checking forecasts.
“Prior to sowing, we know the exact soil moisture status in every paddock (more than 100) because we constantly probe and test each paddock with penetrometers.”
The data is fed into CropMate® and other yield models that forecast expected yields, allowing them to decide which crops to sow in which paddock for the greatest return.
“While a model can be useful, you have to remember that other variables can have a sudden impact on your outcomes – disease, pests and market variability, for example,” Anthony says.
“This is why it is important to combine this modelling with your seasonal forecast so you can foresee how an increase or decrease in rainfall and temperature will affect your yield and your timing.”
Anthony has the added pressure of keeping shareholders happy. The challenge for him is to mitigate the risks as much as he can so that shareholders profit from their investment, even in lean years.
WRI uses a risk-management system that allows input costs to be adjusted, depending on what the season looks like.
“During January and February we start deciding which crops to grow, our budget, and we forecast projected yield. To help with this we’ll look at our soil profile, the current climate and the Bureau of Meteorology’s long-range forecast.”
Anthony updates these projections with current data at three specific trigger points – at sowing time (end of April), at early-to-mid tillering (end of June) and before flowering (end of August). From that point on, he says, they rely on September and October rainfall and stored soil moisture to finish the crops and maximise yield potential.
“It’s about remaining flexible as the year progresses. We don’t want to keep wasting money on a crop that has soaked up all our soil moisture with no rain in sight. At the same time, we want to make sure we are giving ourselves the best chance to reap a maximum yield.”
Managing ‘freakish’ events
Anthony can attest that even the most carefully prepared plans can go wrong.
After an extended drought-affected period, 2009 was a reasonable year for all growers in the area and it instilled hope that 2010 was going to be a “cracking” year.
“We had plenty of moisture in our soil at the start of the season and the forecast remained true throughout the year, with mild temperatures through winter and spring and timely rain,” Anthony recollects. “Our predicted yields were 4 to 5 tonnes/ha. But, come harvest, the rains that were forecast to finish off our plump crops forgot to finish. It rained almost non-stop for two months and, in the end, all of our grain was downgraded to feed.”
Anthony and his team work hard to manage climate variability within their system, particularly those hot spring days, which are predicted to increase in both temperature and number. But in 2010 they could only stand aside and watch what Anthony calls a “freak weather occurrence”.
“If you’ve been farming long enough, instances like 2010 and the floods in 2011 are going to crop up several times in your lifetime and, by many accounts, they are likely to become more frequent with climate change. There’s nothing you can do about them except wait them out.
“What’s important is that you assess how it has affected you, find the benefits – for instance, a full soil profile after the floods which will set up your next growing season – and look at what you have to do to get your system back up and running as quickly as you can.”
The GRDC’s Climate Champions program provides early access to research assessing the impact of climate variability in different agricultural regions and helps growers adapt their production systems. Participants have been selected for their willingness to learn more about the influences of climate variability and to provide leadership to other farmers by sharing their experiences and what they have learnt.
0458 561 156, email@example.com;
Climate Kelpie, www.climatekelpie.com.au
GRDC Project Code EC00003
Region South, North, West
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