C.O.R.N. Newsletter: 2014-10

As of Sunday April 20, no appreciable acreage of corn had been planted in Ohio (http://www.nass.usda.gov/oh ). Although weather forecasts call for some warmer than average temperatures and relatively near-normal rain this week, the forecast for early May is mixed with the possibility of greater rain and lower temperatures than normal. As prospects for a timely start to spring planting diminish, growers need to reassess their planting strategies and consider adjustments. Since delayed planting reduces the yield potential of corn, the foremost attention should be given to management practices that will expedite crop establishment. The following are some suggestions and guidelines to consider in dealing with a late planting season.

Although the penalty for late planting is important, avoiding tillage and planting operations when soil is wet should be a higher priority. 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 years to come. (Keep in mind that we typically don’t see significant yield reductions due to late planting until mid-May or even later in some years).

If you originally planned to apply nitrogen pre-plant, consider alternatives so that planting is not further delayed when favorable planting conditions occur. 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 lb/N broadcast or banded to stimulate early seedling growth. This latter approach will allow greater time for planting. Similarly, application of P and K is only necessary with the starter if a soil test reveals the soil is below the critical level.

Keep time expended on tillage passes and other preparatory operations to a minimum.  The above work will provide minimal benefits if it results in further planting delays. No-till offers the best option for planting on time this year. Field seedbed preparation should be limited to leveling ruts that may have been left by the previous year’s harvest - disk or field cultivate very lightly to level. Most newer planters provide relatively good seed placement in "trashy" or crusted seedbeds.

Don't worry about switching hybrid maturities unless planting is delayed to late May. If planting is possible before May 20, plant full season hybrids first to allow them to exploit the growing season more fully. Research in Ohio and other Corn Belt states generally indicates that late plantings of earlier maturity hybrids are less susceptible to yield losses than late plantings of the later maturing, full season hybrids.

In delayed planting situations, use the optimal seeding rates for the yield potential of each field. Recommended seeding rates for early planting dates are often 10% higher than the desired harvest population because of the potential for greater seedling mortality. However, soil temperatures are usually warmer in late planted fields, and as a result germination and emergence should be more rapid and uniform. So, as planting is delayed, seeding rates may be lowered (decreased to 3 to 5% higher than the desired harvest population) in anticipation of a higher percentage of seedlings emerging.

The week of April 21-26 will feature temperatures a few degrees above normal with below normal rainfall. Normal highs are in the 60s and normal lows in the 40s for the most part. Normal rainfall is about 0.75 inches. We are also entering the period where we see our last freeze this week in any given year. However, as we talked about in March, we expect a late last freeze into early May this year based on years similar to this one. Much of the area will see lows on Wednesday this week near freezing.

The week of April 27- May 3 will be much cooler than normal and wetter than normal. However, confidence is low to moderate in this period with significant weather uncertainty. There is more confidence of being chilly than wet. Temperatures will likely be 5-10 degrees below normal at least in this period. More freezes are expected from April 27-29 across the state of Ohio. A wetter weather system is possible by the middle to end of the week about April 30-May1. There is a low chance of some mixed wet snow on the northwest side of the storm later next week but again confidence is low on that but there is a low risk of that occurring.

All of this means soil temperatures will remain somewhat below normal into early May.

Going forward, May appears to be cooler than normal for the start of the month but will end warmer than normal. Rainfall after the first few days appears below normal for several weeks of the month until possibly the end of the month.

Summer still looks uncertain with the tendency toward near normal temperatures and near or slightly drier than normal weather.

Finally, indications are an El Nino may be in the process of forming. Research by OHRFC and Ohio State University indicates negative impacts on crops yields during El Nino year particularly corn. However, since this El Nino was not going in early spring already and the lag to atmospheric response, impacts may be rather marginal this year.

(Editor's note: Reed Johnson is the lead author on this article) Beekeepers in Ohio suffered substantial losses of colonies over the exceptionally long and cold winter of 2013-2014.  Here in Wooster we lost more than half of our colonies and beekeepers around the state are reporting levels of winter kill in the 30-80% range.  While the frigid temperatures played a substantial contributing role, losses were undoubtedly made worse by all of the problems facing bees today: parasites, diseases, pesticides, breeding problems, and a general lack of summer and fall forage.

Spring is the only reliably good season for bees in Ohio.  Colonies that survived the winter and new colonies brought up from the Gulf Coast are in the process of harvesting nectar and pollen from  spring-blooming trees and weeds  -- but little honey will be made.  This spring bounty will be eaten by the bees themselves as they multiply and grow into large productive colonies that will be able to make a honey crop off of clovers, black locust, alfalfa and possibly soybean in the coming months.  Additionally, robust colonies are needed to pollinate the fruit trees soon and pumpkins, squash and cucumbers later in the summer. 

This spring build-up of honey bee colonies can be directly threatened by corn planting.  Insecticide seed treatments used on corn seed produce an insecticidal dust when they are planted.  Depending on conditions, this insecticidal dust can settle on the flowering trees and weeds that bees are visiting.  Insecticidal dusts are terrible for honey bees because they do not immediately kill the bees visiting flowers.  Rather than causing immediate death, the dust is packed up with the pollen and brought back to the colony where it is can poison young and developing bees inside the colony.

In spring 2013 we sampled pollen from three bee yards in Madison, Union and Clark Counties.  During corn planting all colonies were bringing back pollen containing corn seed treatment insecticides, sometimes at levels that would be expected to cause bee death.  While no obvious bee-kills were observed in our colonies in 2013, we believe that different conditions during planting could have led to a different outcome.   In 2013 corn planting in central Ohio coincided with the start of bloom for fruit trees and hawthorns – extremely attractive flowers for bees – which likely drew bees away from the riskier and somewhat less attractive dandelions, mustards and purple deadnettle growing in corn fields and on field margins. In some years planting may happen before or after fruit tree bloom when bees are intensely interested in weeds growing in and near fields.  This may have been the case in Ohio in 2012 when planting started early and a number of bee-kill incidents were reported.