Crops: The Lynch File: Why corn growers say they can't get an early start

Monday, March 2, 2009

Many reasons are advanced for not planting corn early, but the main one is that growers aren't ready

by PAT LYNCH

Earlier planting over the past five years is part of the reason for the higher corn yields we've been experiencing. In fact, the corn yields in 2008  were the highest ever. Since the Ontario corn crop was planted earlier in 2008 than ever before, I have collected some of the most common reasons why some growers are reluctant to plant early. Each has a logical response.

1. The soil is too cold. Soil temperatures fluctuate in mid-April and early May. Often in Ontario, soil temperatures are warmer in mid April than in mid-May. Typically, we get a few good days in April and often soils turn cold and wet in early May. Corn planted in mid-April may struggle, but it will grow.

2. Ground will get wet and the corn will not come up. In 2005, there was corn in the ground for four to five weeks before it emerged. Granted, not all of it came up on some of the heavy soils, but after five weeks it did emerge and produce a better crop than corn planted in late May. The newer genetics and seed treatments allow the seed to sit in the ground for a longer time before emergence.

3. Ground will crust and corn will not emerge. That used to be an issue. I have seen growers using some of the newer vertical tillage tools, rotary hoes and even a cultivator to help corn emerge. Last year, there was a field on Haldimand clay planted early. At first emergence, there was a one-inch-thick crust and about 11,000 plants emerged. The producer who owned this corn was able to get about 24,000 plants to emerge.

4. It is too cold. I asked one of our location folks early last year if his growers were planting. He said no. When I asked why, he said: "It is too cold." I replied that I had measured the soil temperature and it was not too cold. He said: "No, the air temperature is too cold." Cold air temperature in the spring may not mean cold soil. Often in April, the air is cold but it is sunny. The sun warms up the soil even if the air temperature is cold. If the air temperature is too cold for driver comfort, then use a tractor with a cab.

5. Concerns about frost. In many years, some early planted corn freezes. Usually, this happens at the two-to-three leaf stage and the corn grows back. There is a greater probability of corn yield being low due to an early September frost than a May frost. After telling a grower all the reasons received in 2008 why growers did not get an earlier start, he asked me if I knew the main reason for this. I said, "No." He said the main reason is that growers are not ready.

You should have all equipment and supplies ready by the end of the first full week in April if you want maximum yields in 2009. BF

Pat Lynch, CCA (ON), is head agronomist for Cargill in Ontario.