The benefits of planting corn early

Monday, February 28, 2011

While early planting does not guarantee top yields, it does increase your chances

by PAT LYNCH

In 2010, Ontario farmers carried out a huge on-farm-trial, planting more than one million acres of corn in April. We have never planted that much corn that early. And Ontario had its highest corn yield ever, averaging 164 bushels an acre. There were many things that helped with that big yield. Early planting was a big factor.

There are risks with early planting. Frost is a concern. But Ontario farmers have lost more yield due to an early September frost than because of a May frost. Corn frozen at the two-to-three leaf stage will grow back.

If your corn is frozen at the fifth leaf stage, the biggest concern is frozen leaves that rot and will not allow new growth to occur. Growers have solved this problem with tillage. The most common way is with a cultivator with the rolling basket harrows doing most of the work. The harrows physically remove the dead tissue to allow new growth.

Another risk to early planting is heavy rains resulting in compacted ground. Growers have overcome this problem with tillage. A rotary hoe does a great job if you use it before the crust forms.

If the soil is wet and the predicted weather is sunny, you have a high probability of a crust forming. Under this situation, you should rotary hoe before the crust forms. Other growers use the same tool that you use if the corn freezes. A cultivator with the harrows doing most of the work does a good job of helping emergence.

Can you plant corn too early? Last year, Larry Cowan in Middlesex County planted corn in March. After it was frozen for the third time, it did not come back. Corn planted around April 1 struggled. However, if your land is fit by April 5-10, that is a good time to start. Generally, it takes a few acres to get the bugs worked out, so starting slow is reasonable.

There are some other things to do if planting early. Plant a hybrid with good early vigour and plant fields with least residue first. These would include soybean stubble. Fields that have a lot of residue, such as no-till corn, are more prone to suffer from frost. The extra residue insulates the soil. It does not give off enough heat to counteract the cold air. If you are planting corn after corn early, then tillage helps to warm the soil and minimize the frost danger.

Most growers who plant early increase their population by 10 per cent. This is because, by planting earlier, you expect higher yield. In fields with higher yield potential, higher populations make sense. This higher seed drop allows you to lose some plants in case of frost or poorer emergence.

For early planting work, the ground should be worked as shallow as possible. This may mean taking a few extra hours to make sure your cultivator is level from front to back and side to side. Too many cultivators are not level. When they are in the field, they generally are set so that the shallowest sweeps are working the field at the required depth. This means some sweeps are too deep. These sweeps will bring up cold wet soil and give uneven emergence.

Use a residual herbicide. A cut-rate residual (setup rate) herbicide is money well spent. Since you are planting earlier, you can expect more weeds. Working the ground in May will kill some weeds that have not emerged by mid-April.

Soil is in its best shape when the frost leaves the ground. After that, every rainfall breaks down soil structure. This often leads to more passes of secondary tillage and further soil breakdown.

While early planting does not guarantee top yields, it increases your chances. BF

Consulting agronomist Pat Lynch, CCA (ON) formerly worked with the Ontario agriculture ministry and with Cargill.