Grain Drying Issues for 2014
Grain prices are down, yields are expected to be at a record level, and, for the first time in several years, you may store grain for a longer period of time as part of your marketing strategy.
In addition, more farmers are holding grain above 15% moisture content and blending on the farm, says Gary Woodruff, GSI. “There will be a lot of grain that is more difficult to keep in condition with these three trends,” he says.
Drying grain for long-term storage
Storage moisture and grain temperature determine grain storage life. “To safely store corn through spring, it should be no higher than 15%,” advises Woodruff. “To safely store through next fall, it should be no higher than 14%, and to store for one year or more, it must be at 13%.”
The following chart shows how long grain can be stored at different moisture contents and temperatures. If grain at 16% moisture is held at 80° for 24 days (half of its storage life) and is then cooled to 50°, it then has half of the storage life left at this temperature (or 170 days). This is with one grade loss, if everything goes perfectly.
Maximum Allowable Storage Life in Days
Allowable storage time for clean, undamaged shelled corn at various temperature and moisture levels before a 0.5% loss in dry matter occurs (one grade loss). Off odors can be observed earlier. Actual storage time may be half this if fines and FM are present. Source: ASABE with wider temperature and moisture numbers extrapolated or picked up from other sources.
Holding grain above 15%
“Many today believe they can hold grain above 15% without risk or loss of net income,” says Woodruff. “This is a completely false premise."
If you’re going to hold on to grain for more than a year, it needs to be at 13%. The reason for this is that at 13% there is little or no free water in the grain. Mold and insects can’t access bound water, so they can’t grow or survive. As free water increases, storage life decreases and chances of out-of-condition grain increase. “Safe storage moisture is not an accident; it’s physics,” adds Woodruff.
Above 15% moisture, there is never enough aeration air to properly dry the grain, so water is moved from the bottom to the middle of the bin, compromising the grain. This out-of-condition grain may blend as the bin empties, but it is still there.
It takes about 1% of the corn’s value using LP gas to dry corn from 17% to 15%. When grain heats during the rotting process and loses one grade, 1% or more of the test weight is lost. “At best, financially, you will break even,” says Woodruff. “And the chances of out-of-condition grain increase greatly.
“Holding overly wet grain started gaining popularity in the last 10 years,” he adds. “This last year we’ve seen some of the highest loss rates despite the grain being brought in last fall in pretty good condition.”
His warning: The lure of a faster harvest and lower drying costs from storing above 15% may seem like a better option, but grain at a higher moisture content has no financial benefit, it increases your risk for the grain going out of condition, and threatens your ability to store it long-term.
The best practice for grain bin safety is to never enter the grain bin. “The best way to move toward zero entry is to not allow grain to go out of condition,” advises Woodruff.
Falling through a crust into a cavity, being sucked into the grain as you try to unplug a discharge, or having a wall of standing grain fall on someone all come from grain that is compromised.
This year’s harvest conditions
In the Midwest, recent cooler weather and rains along with the Corn Dent report suggest harvest may be a week or so later with higher grain moistures than average. If the rain and cool temperatures persist, this could slow down harvest further. This would slow down drying and require careful monitoring and management to ensure that grain doesn’t go out of condition.
The North was planted late and hasn’t seen the normal number of heat degree days. “Harvest will be late and wet,” says Woodruff. “But farmers in the North are used to this and prepared to deal with it.” The biggest threat in this region is a frost before maturity is reached. This would stop the corn from drying, test weight and yield would be reduced, and drying and storage would become extremely difficult.