The seven wonders of corn yield

US corn guru says narrower rows will increase yield


Cropping
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US corn guru presents his research to Australian growers.

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Professor Fred Below is a crop physiologist at the University of Illinois.

Professor Fred Below is a crop physiologist at the University of Illinois.

Corn is relatively new to southern NSW but in the United States it's been the most widely produced crop for decades.

This made an IPM Masterclass by University of Illinois crop physiologist and corn guru Professor Fred Below in Griffith an attractive opportunity to local growers and agronomists.

Prof Below has spent years researching corn and presents his seven wonders of the corn yield world across the US.

In Griffith he told irrigators that the top seven factors that can affect corn yield include weather, nitrogen, variety selection, crop rotation, plant population, soil tillage and biology.

"I want growers to know what they are, I want them to know their relative value but more importantly I want them to know how they interact with each other," Prof Below said.

"How can they enhance management practice to really push yields to the next level?"

For Geoff McLeod, a Finley grower who attended the masterclass, pushing boundaries was the aim.

"We've grown corn for about six years now, it's become an important part of our farming business," Mr McLeod said.

"At the moment our yields are averaging 16 to 17 tonnes per hectare.

"But our short- to medium-term goal is to lift our yields up to 20t/ha."

Prof Below said nutrition was one of the factors that interested Australian growers.

Finley corn grower Geoff McLeod said they would take advice from Professor Fred Below and increase plant populations in their corn crop. Photo by Rachael Webb.

Finley corn grower Geoff McLeod said they would take advice from Professor Fred Below and increase plant populations in their corn crop. Photo by Rachael Webb.

"Things like fertigation and better placement can make a significant difference to yield," he said.

Mr McLeod said it was the factor that he believed they had the most opportunity to learn from.

"We'll be looking to change our fertilizer input," he said.

"Prof Below was suggesting we should be putting on more phosphorus, sulphur and zinc than we currently are."

Another element up for discussion was the width of corn rows.

"Australian maize is mostly grown in 76 centimetre rows but in the US we're doing a lot of work in 51cm row," Prof. Below said.

"Narrower rows enable us to manage more plants, inter-step more light and have a bigger root system on each plant."

But for the McLeods and other Australian growers this was complicated in practice since they rotate their corn crop with cotton.

"While we could grow corn on 51cm, we couldn't grow cotton on 51cm because the cotton pickers wouldn't be able to handle the crop," Mr McLeod said.

On the topic of rotation, Prof Below gave the figures for just how big a difference rotating can make to yield.

"In America we do a corn, soy bean rotation and we find that by rotating with soy bean we can produce 1.6t more corn per hectare," he said.

"When we grow corn on corn we actually lose 1.6t per hectare of yield.

"The reason is that you have to manage the stubble."

Mr McLeod said they would take advice from Prof Fred Below and increase the plant population of their corn crops.

"We're currently running at about 80,000 to 85,000 plants per hectare," Mr McLeod said.

"We'll now look at lifting that to 90,000 plants which is closer to the 95,000 plants per hectare Professor Below advised."

Mr McLeod said it was a difficult to find the sweet spot when it came to plant population in corn crops.

"We're looking for the optimum point between the right number of cobs and the right size of the cobs," he said.

"If you produce a lot of cobs they'll be smaller.

"That means you could well be taking your yield backwards rather than forwards."

Mr McLeod said hearing Prof Below draw on a large bank of research data highlighted the need for a major corn research program under irrigated conditions in Southern Australia.

"While we can learn from the Americans, we can't directly translate the findings of their work," Mr McLeod said.

"Our growing conditions are very different which is why their top yields are over 30t per ha and ours are 18-20t per ha."

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