It was a wet spring, a colder-than-normal summer and a fall that’s much colder than normal. And now there are energy shortages due to the cold weather. Farmers may be asking what’s next.
According to U.S. Department of Agriculture’s National Agricultural Statistics Service, 95 percent of corn in Wisconsin reached full dent by Nov. 3. But only 20 percent has been harvested versus 50 percent in a typical year. Much of the corn hadn’t reached maturity before a killing frost hit, which will likely result in reduced test weights.
Harvest is being hampered by wet and snowy fields. And now the cold snap has caused propane and natural-gas supplies to tighten or not be available for grain drying.
With the colder-than-normal temperatures very little field drying will occur during November or December. Allowing corn to stand in the field may result in greater losses than if it’s harvested and dried. A two-year study of field losses found that corn left standing after October reported 3 percent to 5 percent loss in November and 22 percent in December. If corn is allowed to stand in the field all winter a loss of as much as 40 percent will be seen.
If the corn is being used for animal feed, it could be stored in bags or a silo as high moisture corn and used before warm weather in the spring. North Dakota State University grain-drying expert Ken Hellevang said corn can be stored at greater moisture depending on the temperature.
Corn at 20 percent moisture at 40 degrees has an allowable storage time of 90 days.
Corn at 24 percent moisture at 40 degrees has a storage life of 40 days.
Figure 1 shows the allowable storage life for other moisture and temperatures. The corn must be aerated continuously in the bin at greater moisture levels.
Producers could possibly delay drying by one or two months, allowing time for energy supplies to stabilize. Scout fields and harvest any fields that are 24 percent or less. Store in bins without drying. Only dry fields with corn at more than 24 percent until gas supplies become available to resume drying. Or dry corn to about 20 percent; then cool and store it until it can be dried further.
If corn-kernel temperatures are at almost freezing, corn with moisture as much as 30 percent could be stored in a poly bag and held for 60 days until it can be dried.
Ensure grain dryers are working at peak efficiency.
Clean all screens daily.
Don’t dry what isn’t salable.
Screen grains to remove as much foreign matter as possible. That will reduce energy consumption and also reduce the chances of dryer fires. Housekeeping is more critical when outside air temperatures are cold, due to condensation occurring on the dryer. That creates a wet surface for debris to accumulate. The debris may also reduce air flow through the dryer, resulting in reduced dryer capacity.
Check pressure regulators, controls and sensors to ensure they are working accurately.
The efficiency of drying grain is better at warmer temperatures. According to Hellevang the amount of energy to remove a pound of water is about 20 percent less at 200 degrees than at 150 degrees. The plenum temperatures for a continuous-flow dryer are typically in the range of 180 degrees to 230 degrees. If the corn moisture is at more than 25 percent, using warmer temperatures in a continuous-flow dryer will reduce drying costs.
If a producer has a multi-stage dryer and wet corn, the first stage could be set at a warmer temperature and the second stage at a reduced temperature to take advantage of the efficiency of warmer drying temperatures. Caution – corn exposed to temperatures at more than 200 degrees for more than two hours are susceptible to browning or scorching. That’s especially true for corn that is greater than 30 percent moisture. Drying high-moisture corn in two passes may be necessary to reduce heat damage. If the corn is dried to 20 percent it could be put in storage and dried later in the winter or next spring.
Natural-air and reduced-temperature drying are limited to initial corn-moisture contents of about 21 percent. Even at that moisture content, air drying is limited in the northern states due to the colder outdoor temperatures in late October and November. The moisture-holding capacity of air is small at temperatures less than about 40 degrees. Expect to store the wet corn for the winter by cooling it to 20 to 30 degrees and finishing the drying in the spring when outside temperatures average at more than 40 degrees.
Cooling the grain in a bin instead of in a dryer can reduce energy costs by about 15 percent and increase dryer capacity by 20 percent to 40 percent. Cooling the grain slowly will also reduce kernel stress cracks and can improve test weights compared to rapid cooling in a dryer. The corn would be moved to the storage bin about 1 percent to 1.5 percent points more than the desired storage-moisture content, and then aerated until it’s cooled to the ambient temperature. An aeration-fan capacity of at least 0.2 cubic feet per minute per bushel is required. It will take about 75 hours to cool the corn. Condensation on bin walls may be a problem with cold temperatures. That can be remedied by cooling the corn to about 90 degrees before placing it in the bin. Or move the corn to a different bin after cooling to mix any condensation with dry corn so mold formation is reduced. Aerate the grain after moving to a different bin.