Climate change has already reduced yields for Australian wheat growers, thanks to increasingly unreliable rains and hostile temperatures. But our new research offers farmers a way to adapt.
By sowing much earlier than they currently do, wheat growers can potentially increase yields again. However, our study published today in Nature Climate Change shows that to do this they need new varieties that allow them more leeway to vary their sowing dates in the face of increasingly erratic rainfall.
Sowing wheat is a matter of delicate timing. Seeds of current varieties need to be planted at just such a time so that, months later, the plants flower during a window of just 1-2 weeks, known as the optimal flowering period.
In Australia’s wheat belt this window is generally in early spring. At this time the soil is moist after the cool, wet winter; days are getting longer and sunnier; maximum temperatures are still relatively low; and frosts are less frequent. If crops flower outside the optimal window, yields decline sharply.
When Europeans first started trying to grow wheat in Australia, they used varieties that were suited to the cool, wet climate of northern Europe, where the optimal flowering period is in summer. These varieties were much too slow to flower in Australian conditions, and yields were very low. Wheat breeder William Farrer used faster-developing wheats from India to create the Federation variety, which revolutionised wheat production in Australia, earning Farrer the ultimate honour of having a pub named after him.
Federation wheat is a “spring wheat”, moving rapidly through its life cycle regardless of when it is planted. If you sow it earlier, it flowers earlier. For more than a century Australian wheat breeders have bred spring wheats, allowing growers to adjust their sowing time to get their crops to flower during the optimal period. Anzac Day has traditionally been the start of sowing season, after autumn rains have wet the soil enough for seeds to germinate.
Here is where climate change is causing a problem. If farmers sow later than mid-May, the wheat is likely to miss its spring flowering window. But southern Australia has experienced declining April and May rainfall, making it harder for growers to sow and establish crops at the right time. This in turn means crops flower too late the following spring, meaning yields are reduced by drought and heat.
Growers could start sowing earlier, and use stored soil water from summer rain (which hasn’t declined and has even increased at some locations), but current spring wheat varieties would flower too early to yield well. For farmers to sow earlier, they need a different sort of wheat in which development is slowed down by an environmental cue. One such environmental cue is called vernalisation. Plants that are sensitive to vernalisation will not flower until they have experienced a period of cold temperatures. These strains are thus called “winter wheats”.
Ironically enough, the wheat varieties that Europeans first brought to Australia were winter wheats, but they were further slowed by sensitivity to day length which made them too slow to reach the earlier flowering times needed in the hotter, drier colony.
But this problem can be sidestepped by using a “fast winter wheat”, which is sensitive to vernalisation but not to day length. Our previous research showed that this type of wheat was very suited to Australian conditions – it can be sown early but still flower at the right time. In fact, the vernalisation requirement means that this wheat can be sown over a much broader range of dates and experience fluctuating temperatures, and still flower at the right time.
In our new research, we developed different lines of wheat that varied in their response to vernalisation and day length, and grew them across the wheat belt to compare which ones would yield best at earlier sowing times.
We found that a fast winter wheat performed best over most of the wheatbelt, and on average yielded 10% more than spring wheat when they flower at the same time.
We then used computer simulations to investigate how these crops would perform at the scale of an entire farm. Our results showed that if Australian growers had access to adapted winter varieties in addition to spring varieties, they could start sowing earlier in seasons where there was an opportunity. If the rains come early, farmers can use the winter wheat; if they come late they can switch to the spring wheat, which yields better than winter wheat at late sowing times.
This would mean that more area of crop would be planted on time, and yields would increase as a result. If realised, this could increase national wheat production by about 20%, or roughly 7.1 million tonnes.
The main hurdle is that growers do not currently have access to suitable winter wheats. Breeding companies have started work on them, but it will be several years before suitably high-quality varieties become available.
Australian growers urgently need to keep pace with climate change. Although Australia only produces 4% of the world’s wheat, it accounts for 10% of exports and is thus important in determining global supply and price. If global wheat supply is low, prices rise, and it becomes unaffordable for many of the world’s poorest people, potentially causing malnutrition and civil unrest. Steeply rising wheat prices were among the factors behind the food riots that broke out in more than 40 countries in 2007-08, which helped to trigger the Arab Spring uprisings of 2010-12.
The world’s poorest people deserve to be able to buy wheat. But Australian wheat farmers also need to earn a decent living and stay internationally competitive. The only way to meet all these needs is to keep production costs low – and increasing yields by sowing the right wheat cultivars for Australia’s changing climate is one way to go about it.
I have had a most interesting couple of days on the road and in the bush. Currently I’m in a motel room at Woolgoolga, near Coffs Harbour on the mid-north coast of New South Wales, Australia. ‘Hardly the wild,’ I hear you say, and you’re quite right – it isn’t. The weather was beginning to change I noticed on the final leg of my day’s itinerary, so I decided to hide out in a motel room for the night – good decision, it’s pouring outside.
I won’t give all away – I’ll leave the main description of the holiday to the website – but just some of the ‘downlights’ of the first couple of days for this post.
I didn’t arrive at Cathedral Rock National Park until just on dark, but did get the tent up prior to darkness arriving – when it did, it was dark! The campfire took an eternity to get going as all of the timber was damp and by the time I got it started it was time for bed – all-be-it an early night (7.30pm). I had decided to not spend the money on replacing all of the gear I needed to replace for camping, following the loss of a lot of gear over the years due to storage, etc. I hadn’t done much in the way of bushwalking or camping for years due to injuries sustained in my car crash and a bad ankle injury, so I left it all a bit late. I figured that for this holiday I’d make do and replace the gear with quality gear before the next trip. In short, I’ll get by – but it would have been nice to have some good gear just the same. It was a very cold night let me tell you – and long.
When I reached the heights of my first walk today, standing on top of Cathedral Rock National Park, my digital camera decided to die on me. I knew there was something wrong with it during the ascent as it was really chugging away taking pictures. I did get a couple of reasonable panoramic shots on the top of Cathedral Rock before it died, so that was good. I took stills with the video camera I was using, so it wasn’t a complete loss. When I completed the Woolpack Rocks walk I made the trip to Coffs Harbour to seek a replacement and got one for a reasonable price. It’s just another compact and so I will also buy a digital SLR prior to my next trip I hope. My previous SLR was basically destroyed when the camera cap came off during a multiple day bushwalk and all manner of stuff got into it. It wasn’t digital so I didn’t bother repairing it.
So tomorrow – off to Dorrigo National Park I hope and several lengthy walks I haven’t done before. Hopefully the rain will clear.
I have been doing a little work on the planning side of things for my holiday. There have been some changes and these will be explained below.
Firstly, I have decided to push the holiday back a bit. There are a few public holidays during January 2010, so I think I can cope with a few extra weeks at work before needing the break. So instead of taking the holiday at the start of February, I am thinking of taking the holiday for two weeks in late February – early March 2010, or maybe a week or so later than that.
The later time for the holiday will also allow me to save for the trip and ensure I have everything I want for the holiday. I may even be able to get a digital video camera by then, which will be a great plus.
Secondly, the destination has also changed. I won’t be going out west as temperatures out that way are sure to be very hot and somewhat unbearable for any bushwalks I would want to do. The out west option will need to be looked at for a winter holiday (even though night temperatures are bound to be quite cold then). I do have a plan underway for that option also, which will probably mean a holiday in about August – September 2010 (but that is another story for another time). So to make sense of these two possible (probable) holidays in my Blog posts, the earlier holiday will be called the summer holiday 2010 and the later the winter holiday 2010.
So instead of going way out west for the summer holiday 2010, I’m thinking of going west a little (and to the south), before heading back to the southeast and travelling through the far southeast of New South Wales.
Are there any solid plans? Solid may not be quite the word for it, but I am settling on what I’d call a fairly sure itinerary for the first couple of days of summer holiday 2010. The date is certainly not fixed and that is really quite flexible at the moment. The itinerary for the first few days will probably be:
Day 1 Destination – Dubbo
Day 2 Destination – Conimbla National Park
Day 3 Destination – Wagga Wagga
So the next stage of planning will be to iron out the itinerary for these first three days before moving on towards my planned far southeast New South Wales travels.
For information on Conimbla National Park:
An environmental disaster is unfolding on the Queensland coast, with the oil spill from the Hong Kong-flagged ship Pacific Adventurer. The Pacific Adventurer was badly damaged during the Cyclone Hamish weather event last week.
The Pacific Adventurer somehow managed to get caught up in the cyclone despite very early warnings concerning the cyclone. Some 31 containers containing ammonium nitrate were washed into the sea during the cyclone and as this occurred the ship itself was badly damaged, leaking some 230 tonnes of oil into the ocean. The initial report from the ship was that some 30 tonnes of oil had been lost.
The environmental disaster is huge, with the oil now affecting over 60km of coastline, including the eastern coast of Moreton Island. Sea life is being severely impacted by the disaster.
The cleanup is being done at a rate of about 1 to 2 km a day, which means it will take quite some time to complete.
Also of concern are the 31 containers of ammonium nitrate that are still missing and which could further contaminate the region. Navy mine hunters are being called in to search for the containers which remain a shipping hazard.