Summer crops = more options, spread risk and work

Sunflower, sorghum and even cotton are just three possible summer crops showing promise at 'Karkoo'on SA's Eyre Peninsula.

COOPERATIVE research trials at four sites in the Eyre Peninsula of South Australia are investigating the viability of summer cropping in the southern grains zone. One result is that some growers are now starting to include summer crops such as forage sorghum, maize or sunflower in their farming system.

"The agronomy for all these crops is well known, the challenge is to learn how to make these crops profitable and sustainable under local conditions," says scientist Nigel Wilhelm of the South Australian Research and Development Institute. Farmers, local farm suppliers and researchers have become invol ved in the trials.

Their first run came last year in the driest summer in 70 years. They tested the performance of a range of crops including maize, sunflower, safflower, sorghum and cotton. All yielded some grain (see table pJ9 for results), and in some cases they even produced a profit.

For many growers, just getting a harvest and breaking even at some sites was a good result in such a dry year. With the benefit of hindsight, Dr Wilhelm thinks they would do even better now, and he is testing his ideas at seven sites this year. "We were amazed that the last season's trials even survived, especially cotton."

His own farmer trial

Although he is not in the Eyre Peninsula, grower Brett Roberts has caught Dr Wilhelm's optimism for summer crops.

Living on a property some 100 km north of Adelaide in a 400 mm rainfall zone, Mr Roberts has this year planted 260 ha of summer crops, including 50 ha of maize, 80 ha each of sorghum and sunflower, and 50 ha of chickpea as a 'pseudo-summer crop'.

"We sowed into a paddock of sprayedout volunteer barley and other weeds that came up after the last harvest," says MrRoberts.

Both Dr Wilhelm and Mr Roberts agree that this offers a new chance to control herbicide-resistant ryegrass. They say that spraying in autumn and winter with a general knockdown herbicide to get a clean paddock with no seed set takes the burden off grass-selective herbicides.

"If you talk to growers who live where it is normal to summer crop, it becomes pretty clear that they don't have the same problems with weed control that we have down here," says Mr Roberts.

Dr Wilhelm suggests that summer cropping can be justified in areas with a severe ryegrass-resistance problem on this basis alone, once it is at a stage where it reliably covers costs.

Diversity helps with machinery cost control

For Mr Roberts, however, the main attraction of summer cropping is the possibility of getting a more diverse farming system that will help him spread the workload and the risk over the whole year, rather than squashing the entire farming system into a bottleneck.

"The main threat to my long-term profitability is overcapitalisation. Because of the amount of machinery I need to do all the work at once," says Mr Roberts. "For example, I now have two headers, but if I can get summer cropping to work, I might need only one header, and I can keep the profit from my crops rather than watching the machinery eat it up."

Although some new equipment is needed, such as a precision seeder (only necessary for maize and sunflowers), and slight changes to existing configurations to cope with wider row spacings, Mr Roberts' experience and the trials have shown that the cost is minor compared to the so-called 'big-ticket' items. Having just faced another wet harvest, and the ninth wet October in 13 years, Mr Roberts is also keen to try something that will take advantage of this moisture rather than simply wishing it didn't happen. "A big 'ask' in the traditional winter farming system is that we don't want it to rain for five months of the year," says Mr Roberts.

Biggest challenge: dealing with local conditions

With markets for his crops clearly in mind, although he admits that grain sorghum might be a bit of worry locally, Mr Roberts thinks the main hurdle to summer cropping in southern Australia is getting the local crop management and agronomy right.

"We have already seen that we will have to cope with a regime of summer weeds that have been here on the farm, but which until now have not been competing with a crop for moisture," says Mr Roberts. New trials will focus on this as well as on crop varieties and row spacing.

Contact: Dr Nigel Wilhelm 08 8303 9353