Key points Trials for opportunity dryland summer cropping in the Mallee Work done with both winter cereals and summer crops Winter cereals could not handle hot conditions Good fodder making potential with summer lines
WITH a high percentage of wet summers in the Mallee over the past decade, many growers have idly wondered whether there was the potential to scratch in a summer crop to take advantage of the moisture.
Rob Fisher, chief executive of the Irrigated Cropping Council, took the theory one step further and has run a series of trials on dryland summer cropping in the Victorian Mallee.
The short answer is that it is possible on an opportunity basis, but growers will have to be prepared to take a haircut on the following year’s winter crop.
And growers will have some costs associated with getting a successful summer crop going – Mr Fisher said trials using winter cereals had failed.
“We tried to replicate the grower experience, going for a low cost option like some barley left over in the silo, but while it established well, in all cases it was just too hot for winter cereals,” Mr Fisher said at last week’s Birchip Cropping Group main field day at Watchupga.
Mr Fisher said the trials had been sparked by modelling suggesting summer rain events would become more frequent through Mallee regions.
“It’s something that you’d have to weigh up season by season," he said.
"Obviously there would be no point in a dry summer, but one like 2010 when there was 255 millimetres at Kerang for summer, more than the growing season, it could be an option.”
He said the clear best performer in the trial was growing summer crop species for fodder.
“Most years you’d be lucky to get the follow-up rain to take a summer crop through to grain, and there is also the issues in our area in getting the crop to ripen in time, especially if you wanted to plant a winter crop the following year."
However, fodder yields were impressive, with one sorghum crop recording a total of 20 tonnes to the hectare of dry matter.
“It was a good quality feed as well in terms of energy and protein.”
There are a number of side effects growing summer crops.
Firstly, while livestock loved the fodder, it was also attractive to pest species such as mice and locusts.
“When you’ve had a problem with pests and there is green feed among the dry paddocks they will go for it.”
More seriously, Mr Fisher said the successful summer grass crops, mainly sorghum or millet, ripped out a significant amount of nitrogen.
“In some of the trials the winter crop following a successful summer crop had significant yield penalties against neighbouring crops, due both to low moisture and low nitrogen levels.”
There was a compromise – Mr Fisher said trial results using lab-lab, a legume species native to Africa, had been promising.
“In Queensland it is grown reasonably extensively as an alternative to clover.”
He said sowing a summer pulse could stop excessive nitrogen depletion, but added the crops did not produce as much biomass.
Should growers be looking to put in an opportunity summer crop, Mr Fisher said it needed to be sown in late spring or early summer.
“The evaporation rates are less earlier in the summer.”
He said growers needed to have a seed supply on hand ready to sow immediately after a fall significant enough to get them established, in the order of 50mm or more.
The crops needed to be sown at a reasonable depth so the plant could chase the receding moisture level.
Mr Fisher said maize would not be a viable option dryland. “It is just too dry to get it going, forage sorghum and lab-lab look to be the most promising.”