One of the rainiest Aprils on record and a wet, cool start to May have delayed planting of field crops across Ohio and in surrounding states, but Ohio State University (OSU) experts remain optimistic that corn and soybeans can still go in the ground with little impact on yield potential - and the added bonus that when soil conditions become favorable, both crops can be planted without great risk of cold-weather injury.

"Persistent rains have caused major delays in corn planting this year, with only 1% of corn in Ohio and 2% in Indiana planted as of May 1, which is 60% behind last year and 32% behind the average of the past five years," says OSU Extension agronomist Peter Thomison, citing the latest data from USDA's National Agricultural Statistics Service (NASS). "The weather forecast for the next week indicates the likelihood of more rain, so it is probable that many soggy fields will not be drying out soon."

Soybeans also are behind schedule compared with 2010. No soybeans had been planted as of May 1 in Ohio or Indiana, while a year ago 23% in Ohio and 21% in Indiana were already in the ground by May 2.

Despite the unfavorable conditions, Steve Prochaska, an OSU Extension educator in north-central Ohio and member of the university's Agronomic Crops Team, says farmers should not become too anxious or alarmed just yet – but rather should begin planning any changes in crop planting now.

"Even if corn is not planted until May 15, we are still essentially near 100% yield potential," Prochaska says. "If the corn hasn't been planted by about June 1, average yield loss can range from 10% to 20%. Of course, that doesn't include other costs associated with late planting and late maturity, such as higher energy costs for drying and possible harvest loss due to weather issues in the fall months."

In the case of soybeans, studies conducted across the Midwest show that for each day that soybean planting is delayed after May 1, the yield penalty per day can be between 5/8 and 1/4 bu./acre, depending on the year. However, potential yield rewards from early planting should not be used as a reason to plant seed into seedbeds that are too wet, as issues more detrimental than late planting may arise from doing so.

Adjusting planting strategies

Thomison, Prochaska and Robert Mullen, OSU Extension's soil fertility specialist, agree that this year's conditions require growers to reassess their planting strategies and consider adjustments that will expedite crop establishment.

"Although the penalty for late planting is important, care should be taken to avoid tillage and planting operations when the soil is wet," Thomison says. "Yield reductions resulting from mudding the seed in are usually much greater than those resulting from a slight planting delay. Yields may be reduced somewhat this year due to delayed planting, but effects of soil compaction can reduce yield for several years to come."

That's why it's important to keep time spent on tillage passes and other preparatory operations to a minimum, as they will provide few benefits if they result in further planting delays. Ohio State experts agree that no-till or stale seedbed may offer the best option for planting on time this year, with field seedbed preparation limited to leveling ruts that may have been left by the previous year's harvest. Most newer planters, they sayd, provide relatively good seed placement in crusted seedbeds.

Farmers may also need to rethink fertilization strategies. If the original plan was to apply nitrogen (N) pre-plant, growers should consider alternatives so that planting is not delayed any further once field conditions improve. Although application of anhydrous N is usually recommended prior to April 15 in order to minimize potential injury to emerging corn, anhydrous N may be applied as close as a week before planting, unless hot, dry weather is predicted.

"In late-planting seasons associated with wet, cool soil conditions, growers should consider side-dressing anhydrous N (or UAN liquid solutions) and applying a minimum of 30 lbs./N broadcast or banded to stimulate early seedling growth," Thomison says. "This approach will allow greater time for planting. Similarly, crop requirements for phosphorous (P) and potassium (K) can often be met with starter applications placed in bands two inches to the side and two inches below the seed. Application of P and K is only necessary with the starter if they are deficient in the soil, and the greatest probability of yield response from P and K starter is in a no-till situation."

Switching hybrids?

Should growers consider switching from full-season to shorter-season hybrids? Not necessarily. In most situations, Thomison notes, full-season hybrids will perform satisfactorily even when planted as late as May 20-25. Results of studies evaluating hybrid response to delayed planting dates indicate that hybrids of varying maturity can "adjust" their growth and development in response to a shortened growing season – requiring fewer units of heat than the same hybrid planted in late April or early May.

However, there are other factors concerning hybrid maturity that need to be considered. While a full-season hybrid may still have a yield advantage over shorter-season hybrids planted in late May, it could have significantly higher grain moisture at maturity than earlier-maturing hybrids if it dries down slowly. Also, there are many short- to mid-season hybrids with excellent yield potential. As a result, if growers think they may end up planting in late May, they should consider the drydown characteristics of their various hybrids.

Insects and weeds

Insect pest issues should also be considered. Planting after May 25 increases the possibility of damage from European corn borer (ECB) and warrants selection of ECB Bt hybrids if suitable maturities are available. In past Ohio State studies, Bt hybrids planted after the first week of June consistently out-yielded non-Bt counterparts even at low-to-moderate levels of ECB. "Since many corn growers will be planting stacked hybrids this year, which include Bt resistance for ECB, this may be a non-issue unless there's a need to switch to earlier maturing hybrids," Thomison says.

For more information on selecting corn hybrids for delayed planting, download "Delayed Planting and Hybrid Maturity Decisions," a Purdue University/Ohio State publication available as a PDF.

Weed-management strategies will also need to be adjusted for both corn and soybeans this year because of the wet conditions.

"Very little weed management has been done so far this year in Ohio and Indiana, either through tillage or through herbicides, so poor weed control could be another factor limiting yield," Prochaska notes. "Farmers may need to control weeds primarily with herbicides, if appropriate tillage is not possible. Further, 2,4-D has been an intrinsic herbicide tool utilized in pre-plant burndown programs, but due to mandated time restrictions between application and crop planting, it may not be used. As such, herbicide programs may need to be altered."

More information about delayed planting and tillage and herbicide programs is available in Ohio State's C.O.R.N. Newsletter.