Drought years improve growers' use of soil moisture
GroundCover™ Issue: 105 | Author: Sarah Cole
Growers on the gently rolling hills of New South Wales’ south-west slopes rely solely on rainfall for their enterprises, so the eight-year drought from 2002–09 hit production hard.
“We learnt an awful lot from that drought,” says Harden farmer Peter Holding.
Peter runs a mixed cropping and Merino-sheep operation. He and his family crop canola, wheat and some lupins, run a self-replacing Merino flock for wool and produce White Suffolk x Merino lambs from a shed feedlot.
“We got a lot better at managing our moisture; making sure we keep moisture in the soil and increasing water use efficiency. We learnt how to conserve what we get when we get it.”
Looking back, Peter says people might have expected a 12 or 18-month drought, but nobody had ever seen eight years of dry weather. “We probably had two dry periods with a really severe drought in the middle, but it felt like one great, long drought.”
Moisture conservation: the lessons
From his experience, Peter says the key to moisture conservation, is keeping stubble free of any weeds so as to retain all summer rainfall.
“We never used to worry about that, but now it [conserved moisture] can be enough to get us through a year.”
Water use efficiency has also come a long way since the high-rainfall periods in NSW in the late 1990s. Local growers used to combat winter waterlogging by growing fodder rape after wheat or canola, to dry paddocks out.
Also rainfall timing has changed. For example, the average growing season rainfall in 2012 at Peter’s properties mirrored 2006, but the timing was quite different. 2012 brought more rain at the beginning of the season, then dropped off sharply.
Heavy rains in early 2012 contributed to good soil moisture, but then the rain stopped. However, Peter was still able to plant the crop and maintain it. Small rainfalls in September got the struggling crop ‘out of jail’, and another small fall in November helped to finish the crop.
“The difference was the amount of moisture stored at the beginning of the year and our conservation of that moisture.”
Flexible sowing times
Crops in the Harden district often suffer from heat stress in late spring, significantly decreasing yield. Peter tries to manage this risk by moving his cropping program forward by about two weeks.
Although this exposes crops to increased frost risk, Peter says he is happier to reduce heat stress. “The frost risk seems to be just about the same no matter when you sow. And the figures for my area are backed up by the Bureau of Meteorology data in the CliMate app.”
CSIRO’s Dr James Hunt also has research results that back up Peter’s observation. In a dry summer in the southern Mallee, Dr Hunt says, the optimal sowing date is mid-May – but with 50 millimetres of stored soil moisture, the best sowing dates roll back to the end of April or early May. However, the frost risk profile does not change much over this time.
Dr Hunt’s research on frost in recent years indicates that growers may increase average yields by almost 50 per cent by planting a slow-maturing wheat variety weeks before the normal sowing time.
Peter says that given Dr Hunt’s research, his two-week jump forward in sowing dates “hardly seems enough”.
Peter uses an app for grain prices at delivery silos around the country, the new CliMate app for local seasonal predictions, an app to select crop variety, Yield Prophet® software and Twitter communications.
He combines the information from the apps and models with his own experiences.
“They may not be 100 per cent accurate but they’re better than a gut feeling or no knowledge at all. So you take them, you use them and then you blend it with your own knowledge of what you think happens on your farm. Chances are you’ll come up with a better decision than if you had none of that knowledge at all.”
For instance, Peter was checking on the likelihood of getting 500mm of rain between January and May for sowing using the CliMate app. The predicted likelihood was 98 per cent, and Harden received 89mm that week.
Peter also uses the CropMate VarietyChooser app to reduce the volume of information that would otherwise have to be worked through to choose the best variety.
Looking to the future
Combined with climate predictions for southern NSW of drier and hotter conditions with more extremes, cropping is expected to become more challenging, especially in marginal areas in the region.
Peter believes that marginal country is going to become even more marginal and he expects cropping may retreat to the higher-rainfall zones.
It is not a comfortable existence, Peter says, but adds that growers supporting each other goes a long way towards keeping people in business: “That’s the same today as it’s ever been. Many of the farmers out here survive from year to year because their mates are helping them.”
02 6386 2020,
Peter Holding is a participant in the Climate Champion program. Find out more at:www.climatekelpie.com.au/ask-a-farmer/climate-champion-program
GRDC Project Code ECO00003
Region South, North