Back

On October 14, 2017

The combination of cool temperature this summer and some later than normal planting have contributed to later maturing corn and the possibility of a slow corn dry down process this fall. Warm temperatures in late September and early October have helped the situation and if they continue, could help to mitigate the situation in some areas. An early frost in some areas has interrupted the traditional maturity process with corn killed before it reached black layer.

Extension Agronomist Greg Roth states we could be faced with a relatively good crop in some areas with higher than normal drying costs. If you are a corn grower in central or western PA this is probably not news to you now. In some situations this could lead to slightly lower test weight in the grain.

Ohio research has indicated that grain moisture declines about 1% for every 24 to 29 growing degree days. In a warm dry fall with mature grain, they measured about 0.75 to 0.92% per day but in a cool fall they measured about 0.32 to 0.35% per day. At some point in mid to late November, the temperatures become cool and the drying rate starts to become negligible. When temperatures drop in the 20s and below then corn will freeze and dry over the winter.

At the Rock Springs research farm last week, Roth measured grain moistures in the 30% range for 102 day corn planted in mid-May. Later planted corn is likely much wetter. Based on this, Roth suspects there will be some late harvesting this year try to avoid the high cost of drying and as drying systems work to keep up with harvest. There could also be some harvest for high moisture corn where that is an option.

Now is the time to evaluate fields and farms for the crop conditions and make plans for harvesting. Fields with stalk rots and some risk of lodging could be good candidates for earlier harvest. We have also had situations where high yielding corn developed root rots late in November that caused plants to fall over and pull out of the soil during harvest. So keep any eye out for those as well.

Often if corn is standing well, field losses can be low if it needs to stand into early winter. But there is always a risk of an unforeseen weather that can really delay or interfere with harvest.

To Reduce the Risk of Prussic Acid Poisoning- Jessica Williamson jaw67@psu.edu

Warm-season annuals are a widely-used, excellent way to provide forage for livestock in the summer months when cool-season perennials slow their growth – or during the “summer slump”. In most cases, more than one grazing or harvest can be obtained from these warm-season annuals if nitrogen fertilizer is applied at harvest or grazing to stimulate regrowth, allowing the forage to grow well into the cooler days of fall.

However, after a killing frost or another source of damage to the plant, prussic acid is formed which is highly toxic to livestock. Extension Forage Crop Specialist Jessica Williamson tells us all species of sorghum contain prussic acid within the vegetative portion of the plant. Sorghum, johnsongrass, and shattercane contain the greatest levels of prussic acid. Sudangrass contains approximately 40 percent less prussic acid than other sorghums; however, a sorghum x sudangrass hybrid contains a greater level of the toxic compound than sudangrass alone. Improvements in genetic development of forages now allow options for planting varieties of sorghums that contain lower levels of prussic acid, helping to reduce the risk of prussic acid poisoning in livestock.

Another option for incorporating a summer annual pasture or hay crop while reducing the risk of prussic acid poisoning is the use of pearl millet and foxtail millet, which do not contain toxic levels of prussic acid, even after a killing frost. Therefore, it can be grazed any time.

Generally, the greatest levels of prussic acid can be found in the leafier areas of the plant. After a killing frost, toxic prussic acid does not begin to decline until after the leaves have died. To be safe, wait at least 7-10 days after a killing frost to graze or green chop forage. If forages regrow after a non-killing frost, do not graze or feed until the regrowth has reached a minimum of 2 feet in height or 2 weeks, as the regrowth will likely contain high, very toxic levels of prussic acid.

Heavy rates of fertilization and drought can also cause high levels of prussic acid accumulation in these forages even months before a killing frost; therefore, precaution should be taken during these conditions as well. Ensiling these forages helps to reduce the risk of toxic levels of prussic acid, as some of the toxic components escape during the fermentation process as gas. Sorghum silage should not be fed any earlier than 3-4 weeks after harvest as a precaution.

If chopping for silage is desired, a producer should wait 5-7 days after a frost before harvesting. These forages with a risk of high cyanide levels at the time of chopping should be ensiled for a minimum of 8 weeks before feeding and should be analyzed before feeding to ensure the toxic compounds have been reduced to a safe level for consumption.

To Maximize The Value Of Corn Fodder

In Pennsylvania, it is common for corn residue left after combining grain to be utilized as ground cover throughout the winter, serving to protect the ground and helping to eliminate runoff of nutrients and soil erosion. Another common practice is baling corn stover and utilizing it as bedding for livestock during the cold months of the year. The absorbency helps to keep animals dry and warm during the harsh weather.
However, Extension Forage Crop Specialist Jessica Williamson tells us an often overlooked usage for corn residue is its feeding value – either baled or grazed. Mature, non-lactating, mid-gestation beef cattle require approximately 50% total digestible nutrients (TDN) and 7.1% crude protein (CP). In a spring-calving cow herd, cows will not be lactating and will be in mid-gestation during the winter. Corn stover has a 35-55% TDN and a 4-7% CP, and with a little supplementation, can be utilized effectively as a forage.

When the diet of a ruminant animal drops below 7% CP, rumen function begins to decline, causing a decrease in utilization of consumed forages. Therefore, when feeding corn stover as a forage, it is important to supplement a nutritional protein source so ruminal motility remains optimal and animal production does not decline. This is especially important during the winter when nutrient requirements increase slightly.

Supplementing with a high-quality dry hay with optimum TDN and CP will help fill the void in nutrients left by the corn stover, while the corn residue will provide essential fill and fiber for optimal ruminal fermentation.

Studies have shown that grazing crop residue has no negative impact on subsequent crop yields and can improve soil health through the reapplication of nutrients removed and hoof impact. If corn stover is baled and removed, it is recommended that a winter annual be planted to minimize the risk of soil erosion, nutrient runoff, and to provide ground cover for the winter season, especially if manure will be applied to that field.

Additionally, farmers with a grain operation and no grazing livestock could lease their fields with corn residue to neighboring livestock operations for fall grazing and obtain an additional income source.

Quote Of The Week: “Twenty years from now you will be more disappointed by the things that you didn’t do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.” Mark Twain