Grain crops are expanding into traditional sugar cane country in Far North Queensland. Bernie Reppel talks to one grower about the way he is applying new crops to his Atherton Tableland farm
[Photo by Bernie Reppel: Immersed in the expansion of cropping: grower Doug Rankine.]
You have to prod Doug Rankine to get him to admit that his average yields of maize and peanuts are at the higher end of the scale for North Queensland"s Atherton Tableland.
"It depends on what foolish things I have tried," he muses. "Like this summer, when I planted a non-tableland-bred maize variety ... and paid the price. Its yield was not as good as I am capable of getting. It went about seven tonnes to the hectare. My tableland adapted variety went eight tonnes."
Queensland"s Department of Primary Industries and Fisheries (QDPI&F) has had a maize breeding program on the Atherton Tableland for many years, with its initial purpose the development of varieties adapted to the varying climates of these elevated production areas west of Cairns.
While the GRDC has encouraged the breeding program to target varieties for other maize production areas in the northern region, developing varieties for the different climates of Far North Queensland remains a major challenge.
Ian Martin, the QDPI&F"s maize breeder at Kairi Research Station, explained to growers at a recent Grains Research Update in Atherton that their relatively small Far North Queensland maize industry was spread across four different environments.
He said maize hybrids interacted more strongly with locations than with seasons in Far North Queensland, so it was essential to choose the hybrid best adapted to particular growing conditions.
Mr Rankine"s 1200 hectares are at Walkamin, on the drier, less elevated, northern end of the Atherton Tableland. Rainfall averages a bit more than 500 millimetres a year, but as Mr Rankine points out: "It all falls in two months, January-February or February-March.
"Fortunately we have plenty of irrigation water - a 4000 megalitre allocation from the Tinaroo Dam, built on the Barron River in 1958. Apart from a small area that we can flood, all irrigation is by centre pivot, two full circles and six part circles."
Mr Rankine has about 360ha under cultivation, with much of the farm being steep and rocky where it runs down to the Barron River and Tinaroo Creek.
"It"s what we call forest soil, mostly red basalt but with some swamp areas that had to be drained sub-surface, and patches of yellow-grey clay - perhaps 40ha altogether. And one paddock has got soil every colour of the spectrum."
Mr Rankine"s timber milling family bought the farm in 1967, but he has only been fully involved with it since 1994. A fitter by trade, he looked after the heavy equipment in the timber business before taking over the farm.
The Rankine farm rotates grain crops - predominantly maize and peanuts - with sugar cane. The 140ha under cane in 2005 is well down on the 240ha of five or six years ago, and could fall further.
"We started in cane about 10 years ago, but I don"t know how much longer we will be in it, with the sugar price the way it is," Mr Rankine says. "We had something of a double-whammy about four years ago, when the price crashed and - because we depended on just one cane variety - orange rust caused a lot of crop damage."
Cane grub - the larvae of the grey-back moth, the native insect that cane toads were imported to control - is also a major problem. It reduces the number of ratoon crops of cane the Rankines can grow, and also indulges its taste for the grain planted nearby.
"Grubs can be particularly bad if you plant at a susceptible time. I have seen metres of rows of peanuts and corn looking like they are in drought; virtually dead.
"They love peanuts especially. They nip the tap root off and the plant is finished. They proceed along the peanut row doing that.
"There"s been no major catastrophe in the last four or five years, but the Bureau of Sugar Experiment Stations people still come here when they are looking for some grubs. They say they are easier to dig out in peanuts."
Paddocks being taken out of sugar cane are ploughed as early as possible in the harvesting season - June to November - and sown to a broadleaf crop like peanuts or navy beans that will allow selective spraying of sugar cane regrowth and other grass weeds.
Mr Rankine likes to maintain this broadleaf crop/ grass crop (sugar cane, maize, sorghum) rotation, however, Hamill grass (a giant guinea grass) is a serious problem in some paddocks.
Mr Rankine has doublecropped for the past five or six years, although he says it"s like owning a dairy farm - you can"t get away.
"Where possible I rotate peanuts and corn, generally watering up the corn," he says. "Sometimes it doesn"t work, like recently when the corn was harvested late because of a contract problem. That forced me into sorghum, which is a bit quicker and which I can possibly spray-out and harvest early to get back to my regular rotation.
"And frost can be a concern. I have seen enough here to roll the corn, and that has to be a consideration at planting time along with the insect problem."
Mr Rankine soil-tests before every crop and all fertilising is done through the irrigation system, apart from starter fertiliser.
"This soil ties up phosphorus in a big way, and I have to be careful to band my starter fertiliser a couple of inches beside or below the seed," he says.
For more information: Doug Rankine, 07 4092 2636