Corn School: Flag Test Measures Emergence Impact


If a corn plant emerges one, two or three days after its neighbour, will it yield less?

Real Agriculture resident agronomist Peter Johnson is determined to find out. At the SouthWest Ag Conference last January, National Corn Growers Association yield contest champion Randy Dowdy challenged growers to plant a flag test on their farm to measure the impact of late-emerging plants.

Dowdy, who harvested a record 503.7 bushels per acre on his Georgia farm competition plot in 2014, believes that even emergence is indeed the silver bullet when it comes to corn production.

Corn yield champion Randy Dowdy says farmers need to challenge conventional thinking to produce higher yields
National Corn Growers Association yield champion Randy Dowdy believes that even emergence is indeed the silver bullet when it comes to corn production.

“If you want to make 300-bushel corn, it starts with a 300-bushel stand. Strong populations are good, but what’s most important is that all the plants emerge at the same time,” he said. “Those smaller, later-emerging ears produce fewer kernels that weigh less and the yield impact can be 20% to 50% as 12 to 36 hours go by.”

Dowdy’s idea caught Johnson’s attention and this summer he’s planted a series of flag tests on his farm at Lucan, Ontario. In this Real Agriculture Corn School episode, Johnson takes us on a tour of the three flag test plots he’s planted, discusses test set-up, how they will be managed and what he hopes to learn throughout the season. He’s already noted emergence differences of two to three days from early to late-emergers in his conventional and no till plots. He’s also seeing even longer gaps between emergence in his ‘green’ plot where he planted corn into a cover crop.

Real Agriculture will revisit the plot during the season and again at harvest when Johnson will have results to share with our viewers.

Click here for more Real Agriculture Corn School episodes.

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