As the weather warms this spring, and grain bins start to heat up, farmers need to keep a watchful eye on grain temperature and moisture levels to prevent spoilage and shrink. With commodity prices at lower levels these days, you can't afford losses.
"Start checking your stored grain more frequently. Once a week is best," says Charles Hurburgh, Iowa State University Extension grain storage specialist and professor in charge of the Iowa Grain Quality Initiative. He has already heard reports of hot spots in bins and has handled some calls from farmers seeking advice about what to do with the grain in those situations.
There's more wet corn in storage this spring. Grain moisture was at higher-than-normal levels coming out of fields and going into bins last fall. Farmers need to be extra vigilant of hot spots, moisture migration and condensation this spring. If proper storage practices were followed through fall and winter, grain temperatures should be in the 30 to 40 degree range now, he says.
Check stored grain temperature often to prevent future problems
Wet grain will spoil quickly if grain temperatures rise. Condensation can also be a problem. If needed, now is the best time to run drying fans and aeration systems because dew points are still low. Farmers will be able to preserve proper temperatures without adding moisture.
Hurburgh suggests farmers inspect the headspace of bins (which warms up first) for condensation. If moisture is found, ventilate using roof fans if available. They are a smart, economical way to protect grain without having to warm the grain mass. "The forecast looks good going forward," Hurburgh notes, referring to operating aeration systems and fans. "The last couple of weeks were good, too. We had dry air, which is what we need with the wet corn in storage."
Pay attention to the dew point of the air when aerating grain
Evaporative cooling will take the temperature to near the dew point. Dew points may not change much through a day, even if the temperature rises. Fronts and weather systems are likely to change dew points. For example, on March 21 the dew point was about 25 degrees, although the air temperature was in the 50s. "This would be a good aeration day because the grain will not warm up, and some moisture will be removed," says Hurburgh. "This condition would be ideal for wet corn in a drying bin—you'd be drying without sacrificing grain storage life to warm temperatures."
As outdoor temperatures warm up, the ability to maintain cold grain temperatures (below 40 degrees F) becomes more difficult. If you have to start your fans to dry wetter corn to prevent condensation or cool a hot spot it's important to transition the grain temperature completely throughout the bin. For a drying fan that has a 1 cubic-foot-per-minute-per-bushel flow rate, this will take about 15 hours. For an aeration fan of 0.1 cfm per bushel, it will take about 150 hours. Low humidity days have an advantage because grain temperature may not change much due to evaporative cooling, says Hurburgh.
You want to avoid warming stored grain to above 50 degrees
If at all possible when aerating grain, avoid warming it to above 50 degrees. "Some warming of grain is inevitable as outside air warms up, but you should not intentionally aerate grain to above 50 degrees," he says. "Insect activity and spoilage organisms will increase at that temperature. So when air temperatures are very warm, which we have most of the summer, you want to avoid running aeration fans on a routine basis."
Many elevators in Iowa are reporting corn coming in at 18% from on-farm grain storage the past couple weeks. Brian Kemp, a northwest Iowa farmer, recently hauled a few loads of corn to market that came out of storage at 16.5% to 17% moisture. "I had my fans running for 10 days," Kemp says, noting he turned them off earlier last week. "I think there was some moisture migration during the winter."
Plan to sell or feed the wetter corn first; it has less storage life
"Plan to sell or use the wetter corn first since much of the storage life has been used up, even at cold temperatures," says Hurburgh. "The likelihood of spoilage later in the summer, when even dry corn is at risk, is much higher." Based on USDA estimates, a considerable amount of 2014 crop corn will have to be kept in condition over a year in storage, based on supply/demand and price projections for 2015 marketing year.
While corn is the chief concern in storage, farmers typically don't have to worry as much about storing soybeans. If anything, beans are usually too dry rather than too wet if stored for long periods. Hurburgh advises farmers not to artificially add moisture to beans in the bin using outside air. It could cause beans to swell and the bin to burst.
Smell the first air that comes out, and measure its temperature
If bins don't have temperature and moisture monitoring equipment, Hurburgh says it will be necessary to run fans periodically whether there is a need or not. Turn the fans on and smell the first air that comes out of the bin. You should also measure the temperature of the air that comes out of the grain mass, each time you turn the fans on. If it's warming up, you probably have a hot spot developing.
Hurburgh says temperature monitoring equipment is worth the investment. A 100,000- to 150,000-bushel bin typically needs five monitoring cables, which will cost $2,000 to $4,000 or more. Automated systems are higher yet. "Pay your money. The savings in shrink and unnecessary bin aeration, especially in large bins, will pay for itself pretty quick," he adds.
Grain bin monitoring systems save time, and save grain, too
Several companies sell grain bin monitoring equipment and systems. IntelliFarms, based in Missouri, developed a web-based system called BinManager that takes the worry about of long-term storage. The system monitors moisture content and temperature of grain using cable mounted sensors. It will notify the farmer via text message or email or both if there's a problem.
The user tells the system what type of grain is being stored and the target moisture content. BinManager automatically knows when to run fans to prevent spoilage, shrink and over-drying. "Farmers are focused on planting now," says Dave Ahern, an IntelliFarms sales rep and grain specialist in eastern Iowa. "With the warm weather, there are a lot of questions about when to run the fans. But this system will decide that for you. BinManager is automatically adjusting the parameters, allowing our customers to focus on spring fieldwork."
Grain bin monitoring systems have become more advanced
HTS Ag, based at Harlan in western Iowa, installs and services OPI Advanced Grain Management systems. Terry Johnston, account adviser for HTS Ag in Parkersburg, says the company approaches grain storage with a holistic approach. It includes initially storing grain at the proper moisture content, and being vigilant in checking it and using technology to keep it in good condition.
The basic OPI system consists of monitoring cables. Temperature and moisture readings are provided by manually plugging into the system at the bin site or remotely via a wireless mobile device. Based on readings, the farmer operates fans and aeration as needed to dry grain to the desired moisture and keep grain in condition.
The company also sells and services a more advanced system, the IntegrisPro system, which uses monitoring cables, a weather station and computer to automatically run fans and aeration to dry grain to the desired moisture and keep grain in condition. "We ask growers a lot of questions to make sure we know what type of system they need," Johnston says. "It takes the guesswork out of grain dry-down, conditioning and long term storage."
For more information about aeration and stored grain management, visit the Iowa Grain Quality Initiative site iowagrain.org.