When is the right time to switch to soybeans?

Corn growers that have their crop planted are happy to watch it grow while some 30 percent of the crop remains unplanted, making these farmers more anxious by the day as they struggle with nature to finish the job. Since we are well past the optimum planting date (May 10) for maximum corn yields, we know each day brings a predictable decline in yield.

I spoke with Dr. Wade Thomason, Crop Specialist at Virginia Tech who explained that yields will drop by about one half of a bushel per day for the first 10 days past the optimum date. After that we can expect yield to decline even faster, falling by as much as eight tenths of a bushel per day.

If you expect to grow 100 bushels of corn per acre when it is planted by May 10, and you wait until May 20, your yield should drop down to 95 bushels per acre. After May 20, out data says you can expect yields to drop even faster. If your corn is still not planted by the time you read this article in early June, your expected yield will have declined down to about 84 bushels per acre.

My original question for Dr. Thomason was: when should producers stop planting corn and switch to beans? He pointed out that the current economy makes this a difficult answer. Older information is only fair in predicting today’s new economy. So, he urges readers to be careful in choosing one date as a cut off. However, data our research station in Orange says that around June 12 soybeans will take over as your best choice. 

One fact not discussed is the land already prepared with corn herbicides. This will prevent beans from being planted and there really is no choice here. As for untreated fields, soybeans are one of your options if time runs out for corn.

Remember the upcoming Virginia Ag Expo by marking you calendar for Aug. 6 from 7:30 a.m. to 3 p.m. This will be the largest field day held in Virginia! It will be held in Hanover and King William Counties at the John N. Mills & Sons Farm, a large diversified operation consisting of corn, soybeans, wheat, and beef cattle.

Corn and soybean test plots will include studies that examine seeding rate, weed control, seed treatments and fungicides, soybean planting dates include early, mid and late season plantings, along with barley versus wheat beans. Attendees will see pasture management, a unique silage storage system, wetlands and stream side mitigations. Companies will display their products and services under a large tent and farm equipment will be on display. A nice barbecue lunch is planned with all of the trimmings.

Advanced registration is recommended. Send $10 per person including a list of names to:
Virginia Ag-Expo, 17000 Sandy Point Road, Charles City, Va. 23030 by July 28.