A TOUGH 2018-19 season and improved irrigation technology has inspired a new crop along the river flats at Murray Bridge, South Australia.
Dairyfarmers Ian, Julie and Trent Mueller worked with Platinum Ag agronomist Matt Howell, Meningie, SA, to sow 25 hectares of maize along irrigated flats.
Trent said they had been considering a new crop for the past year but were inspired to go ahead following a “rubbish” 2018 and soaring feed prices, with maize selected for its water efficiency.
“Water is a scarce commodity so we were looking at the economics quite closely,” Mr Howell said.
He said preparation had been key in sowing the crop.
“Maize is quite a finicky crop – you’ve got one shot to grow it so you need to get the paddock right,” he said.
Mr Howell said they had been particular about soil testing, leading them to spread gypsum, as well as a pre-sowing mix of urea, potash and Granulock zinc.
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The crop was precision sowed, with 60 kilograms of Granulock Zn at 60kg/ha and Pioneer P0725 at a rate of about 110,000 seeds/ha, before an emergence date of November 20.
Mr Howell said previous density trials in the Meningie region, under pivot irrigation, had shown sowing at a higher rate resulted in finer stems and more cobs, which meant a total higher yield and quality.
He said precision sowing was also important for even maturity of the crop.
The crop is made of four early to mid-maturing varieties, selected to ensure the crop was off by mid-March to allow time to re-establish winter ryegrass.
Mr Howell said Pioneer hybrid P0725 was his pick of the four varieties – which included P1197, P0865 and Advanta 440ME – so far, saying it showed good early vigour.
Waterlogging has been the biggest hurdle, with one-fifth of the crop lost when rain fell in November, following the first irrigation.
Mr Howell said there was a clear difference between the areas of the crop with good drainage and other areas, particularly at the tail of the watering.
Despite that, he said the crop had performed to his expectations for most of the bay and exceeded expectations along the edges of the bay.
Mr Howell said it was important to make sure adequate nutrition was available, with it a “nitrogen-hungry” crop.
“Maize is a high-value product; you’ve got to have a system to feed it,” he said.
Mr Howell said, based on a yield of 16 tonnes/ha to 18t/ha, the crop would cost about $220-$240t/ha to grow.
But he said the maize was also comparable to a grain crop, particularly wheat, in terms of feed quality.
Trent said the maize had impressed him enough for it to become a regular in their rotation from next year.
“It’s quite impressive how it is coming along,” he said.
“You go down every couple of days and can see the changes.”
Trent said he was particularly impressed with the efficiency, estimating – just before the fourth irrigation – it had used about 3 megalitres/ha to 3.5ML/ha, with another three expected, each about 1ML/ha.
“The goal was to find options to grow bulk amounts of feed without horrific amounts of water,” he said.
Trent said the new crop could help them grow more feed and aid self-sufficiency.
He said the irrigated maize would be incorporated into a mix, along with brewers grain and potatoes, to go out onto a feed pad.
But he said this trial would likely not be possible if they had not recently upgraded through the SA River Murray Sustainability Irrigation Industry Improvement Program.
Alongside laser levelling their paddocks, they installed a pipe and rise system, which Mr Mueller said vastly improved their control when watering.
He said they could water more quickly and accurately, making irrigation more efficient, with estimated savings of up to 1 megalitre a hectare.
There are three other dairy farms growing maize along their river flats this season – two at Jervois and one at Monteith – totalling 92ha.
Mr Howell said it would be possible to compare some of the management decisions across the flats.