Adjusting Corn and Soybean Management from A Wet April

by Greg LaBarge, Fulton County

We have gotten use to an April start to planting over the past several years. But in the late 80’s and into the 90’s we were often hesitant to start planting until we hit May 1. We are better equipped to handle a wet spring than we were 15 years ago. With increased planter sizes, multiple planters/drills on the farm 10 days of dry weather will change the landscape in a hurry for both corn and soybeans. Some recommendation from the last Crop Observation and Recommendation Newsletter will be helpful as we change some strategies. Here are a few highlights from that newsletter:

Corn. The focus is now planting. Planting date penalties are still minimal. The key thing will be to do everything right at planting. Avoid mudding in a stand since this tends to have a bigger penalty than planting date. Do the minimum amount of tillage to get an adequate seedbed. Plan to sidedress nitrogen. Whatever preplant N was planned can be substituted for minimum 30 lbs of starter N and then sidedress. If you have to preplant N, be sure to allow adequate time between anhydrous application and seeding (7 days, long if hot and dry) or be sure you are deep enough to prevent contact with the seed to avoid germination problems. P and K at planting are only needed if soil test levels are below critical levels. Plan to use your current hybrid mix up until May 20th and focus on longer season hybrids first. Soil tempertures have warmed to the mid 50-60’s. You can think about lowering seeding rates 3-5% over desired harvest population versus the 10 % rate suggested with early planting.

Soybeans. We are still a long way from any critical dates for soybeans. Yet we want to take advantage of a full season and thus many will be planting both corn and soybeans. With wet soil we want to relook at the seed treatments we have and are we well protected against phytophthora (or Pythium if we stay cold). Are protections in our seed treatments at the maximum (or minimum) rates for these water molds particularly when the field is a problem field identified from past seasons? Later planting dates reduce the days till canopy formation thus we want to look at row spacing as planting dates become later. The table 5-3 is from the Ohio Agronomy Guide and looks at row spacing and canopy closure. We want to be at full canopy as we enter flowering at the end of June. All winter we discussed resistant weeds and the importance of a clean start. In many cases a good insurance to accomplish these goals is 2,4-D in the burndown. The downside is the standard 7 day waiting period between application and planting when using 2,4-D. If at all possible it would be good to stick with the plan. But if we can not wait Mark Loux has outlined some options. One option is glyphosate alone using a rate of 1.5 -2.2 lbs ae/acre with a residual. Option two is glyphosate, Sharpen and MSO but this limits residual choices. Option three is Ignite plus residual in 15 GPA and proper nozzles. Option four is to substitute tillage but need to be aggressive enough to uproot the plants entirely or we get an uncontrollable weed left. Cost for all of these options will likely be higher but with today’s prices easily justified. Read Mark’s article for full details.

See issue 2011-10 for a full discussion of the topics.

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