Key tips farmers should not ignore for late planted corn

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Corn planting is already behind this year. We received over 13 inches of rain across the county in April. Crop fields are extremely waterlogged. With more rain this past weekend, it will be days before fields are suitable for planting, assuming rain is not in the forecast. Past research suggests that we start losing yield potential for corn planted sometime after May 5 to May 15 by about 1 percent per day. By the time you read this, we will already be in that time frame. You are in a tough spot, so what do you do? UK Extension Grain Specialist, Chad Lee offers some timely advice to farmers.

1. Wait one more day. Mudding in corn may work if we get timely rains every week throughout the summer. However, mudding in often leads to sidewall compaction and restricted root growth which leads to other problems in the growing season. If you are able to choose between mudding in the corn or waiting the extra day for soils to dry, you will be better off to wait that extra day. The challenge with waiting one more day is 1) you have a lot of acres to get planted and 2) no one can guarantee if that one more day will be dry. So, if you mud in corn, then be prepared to scout those fields for problems later. Maybe we will get timely rains every week and this won’t become a problem.

2. Slow down. Most planters work best at about 4 to 6 mph. Slower speeds allow for more uniform placement of seed. I know, you are already late getting corn planted and I’m asking you to drive slowly.

3. Check planter depth in every field. Soil moisture will affect planting depth, with the planter sinking deeper in wetter soils and shallower in drier soils. You are targeting a depth of about 1.5 inches. The depth settings on your planter will be correct for one field and off on the next depending on soil type, soil moisture and residue. Getting the correct seed depth will lead to better results later in the season. Take the time to check planter depth in each field.

4. Keep seeding rates the same. With the potential for reduced yields, some farmers may be tempted to lower the seeding rate. Keep the seeding rates the same as you normally would for a field. The recommended range is about 24,000 to 30,000 viable seeds per acre, with the higher end of the range for more productive soils. If your normal practice is to plant more than 30,000 seeds per acre, you may not need to be as high.

5. Keep hybrid maturities the same for May, switch for June. If you can get the corn planted in May, you are probably safe to stay with the seed you already have. Once we get into June, you may want to switch to an earlier-maturing hybrid. If possible, you may want to switch to a cornborer Bt hybrid, for any additional corn to be planted. Research has shown a yield advantage to cornborer Bt corn planted early May or later.

6. Control weeds. Late-planted corn normally germinates and emerges much quicker than early-planted corn. Weeds will also grow a little faster this time of the year. You likely have some yield reductions from the late plantings. Do not add to the problem by letting weeds get too big. Depending on the year, weeds that emerge with the crop and reach six inches in height will reduce yields. Because the corn should grow a little quicker, be ready to spray your postemergence treatments earlier than you normally do. Count collars on the corn (fully emerged leaves) before spraying to make sure your corn is not too mature for the herbicide application.

So, planting corn late usually results in reduced yields. However, this is not your usual year. Perhaps our heat units will catch up and we will have the water we need for a little faster corn growth. While we are not off to the best start, maybe, just maybe we can have a good finish.

Michael Pyles is Trimble County’s Cooperative Extension agent for agriculture.