Frequent rain events and wet fields have delayed corn and soybean harvest this year. In the case of soybean harvest, winter wheat was the next scheduled crop in the rotation.

The issue is that from a yield potential perspective, the best time to plant winter wheat is the 10-day period starting after the fly-free-safe date, which in Wayne County is Sept. 26.

Wheat planting that is delayed outside of that time frame has an increased risk of reduced fall growth and reduced winter hardiness.

This adds up to a reduced yield potential.

Of course, our fall weather influences the degree of that risk, but according to the Ohio Agronomy Guide as winter wheat is planted more than 28 days beyond the fly-free-safe date, yield potential begins to decline dramatically from 77 percent of full yield at 28 days to about 30 percent at 40 days beyond.

In a recent OSU Extension CORN newsletter article, Laura Lindsey, Extension small grain and soybean production specialist, offered the following advice regarding a delayed winter wheat planting: "There is still time to plant wheat, but the window is closing. Wheat planted 3-4 weeks after the fly-free-safe date can achieve the same yield as earlier planted wheat if freezing weather does not occur until late November or early December. However, as we enter three to four weeks after the fly-free-safe date, growers should plant at a higher seeding rate than the regularly recommended rate of 1.2 to 1.6 million seeds per acre for 7.5-inch rows (that is about 18 to 24 seeds per foot of row with normal sized seed) to compensate for fewer tiller development. Instead, plant at a rate of 1.6 to 2.0 million seed per acre. The number of seeds per pound and germination rate are important for determining the correct seeding rate and drill calibration. There are fewer seeds per pound of large seeds than per pound of small seeds. The number of seeds per pound can be found on the seed bag."

Additionally, late planting also means plants will be smaller than normal when entering dormancy, have smaller and more shallow root systems than normal making them more susceptible to heaving next March. The best heaving control is to get the seed placed between 1.0 and 1.5 inches deep when planting and to plant no-till. These two practices combined will reduce heaving potential by more than 95 percent." Forage toxicities and frost events

Livestock owners need to be aware that frost and freezing weather can result in some forage species becoming toxic with regard to livestock consumption. The issue is that some forage species contain compounds called cyanogenic glucosides in their cell compartments. Frost and freezing temperatures damage plant cell membranes, allowing those compounds to mix. The result is production of hydrogen cyanide, more commonly known as prussic acid. Grain and forage sorghum, sorghum-sudangrass hybrids and sudangrass are all warm season annuals that have this potential for prussic acid or cyanide poisoning following a frost event. Some other species that may be in or near pastures and hay fields and that are known to develop toxic levels of prussic acid include Johnsongrass, shattercane, black cherry, elderberry and chokecherry.

The formation of hydrogen cyanide or prussic acid occurs very quickly, within minutes to a couple of hours after even a light frost. Cyanide is one of the most rapidly acting toxins and with a lethal dose, death can happen quickly, within a 15 to 20 minute time span. Do not let livestock graze any plants in the sorghum family immediately following a frost event. However, because prussic acid is actually a gas, it will dissipate with time as the plant dries out with the passage of time. For this reason, chopping these plants for silage or using them for dry hay production is a better option than grazing after a frost.

After a frost, cyanide is more concentrated in young leaves and tillers than in older leaves or stems. If grazing is your only option to utilize this forage, take these precautions:

• Do not graze on nights when frost is likely.

• Do not graze after a killing frost until plants are dry, which usually takes 5 to 7 days.

• After a non-killing frost, do not allow animals to graze for two weeks because the plants usually contain high concentrations of toxic compounds.

• New growth may appear at the base of the plant after a non-killing frost. If this occurs, wait for a killing freeze, and then wait another 10 to 14 days before grazing the new growth.

• Use heavy stocking rates and rotational grazing to reduce the risk of animals selectively grazing leaves that can contain high levels of prussic acid.

More information about use and management of frosted forages is available on the Wayne County Extension web site at http://go.osu.edu/agwayne.

Rory Lewandowski is an OSU Extension agriculture and natural resources educator and may be reached at 330-264-8722.