The weather in Montana has been unique and challenging for grain farmers. Montana Farm Bureau contacted David Weaver, PhD, associate professor, Department of Land Resources & Environmental Sciences, Montana State University to glean helpful information regarding storage and drying of harvested grain.
“For many grain farmers, 2013 has been an unusual year, beginning with the weather patterns early in the crop season. Harvest has been equally unsettling, with all of the usual concerns compounded by very late planted crops that are slow to ripen and also by the inability to harvest ripe crops due to an unexpectedly wet late summer,” Weaver said. “These conditions require that growers pay close attention to good storage practices as they get grain into the bin. These are always applicable, but there are times when failure to adhere to them will result in a more rapid loss of quality.”
Grain that is now in storage on-farm or in elevators needs to be dry enough for good preservation. “Make sure that your wheat and barley moisture contents are at or below those acceptable for storage. A good general rule is that grain should be stored at a moisture content of 12% or less. If your grain is harvested at higher moisture content (say 17%, for example) you can use a drier if you have access to one. Otherwise, you need to use high airflow or pressure aeration to dry the grain mass in the bin,” explained the MSU professor. “Running aeration fans continuously, except when the relative humidity outside is very high - like when it is raining - is the best way to dry. You should also monitor the moisture and cooling front as it moves through your grain mass. It is not helpful to use the fans to move moisture only to the center of the grain mass, it must move through the entire bulk and into the external environment.”
Weaver said another component in preserving grain is to allow for heat and moisture exchange in the peaked bin headspace. A bin that is filled to maximum capacity creates a moist microenvironment at the peak of the grain mass, which allows for insect population growth and microbial spoilage.
“The best way to deal with this is to use a deflection or mechanical spreader when filling your bin and watching the grain level as the bin fills. Using a spreader also prevents fine material from forming a moisture laden core in the center of the grain mass,” Weaver noted. “An alternative approach, but less desirable, is to draw out a volume of grain after filling so that the grain mass is effectively leveled. This ‘removal of a load or two’ will create the desired airspace, help to level the grain mass, and remove some fine material. However this “double-handling” approach is not as effective as simply using a spreader and taking care not to overfill the bin in the first place. Using a rotary grain cleaner to remove fine material is another way to eliminate problems that may be caused by fine material.”
Finally, there is temperature management which can be undertaken immediately if the grain is adequately dry at first storage. “Simply use the air temperature to reduce the grain temperature by running fans at night or on cold days,” Weaver advised. This can be accomplished manually or by using automatic controllers and sensors. Greater airflow with adequate ventilation for pressure is always desirable.
“Temperature management is very effective in reducing or eliminating insect populations and associated spoilage. Insects are less damaging and slower to reproduce once grain temperature is below 70 degrees, but here we have the advantage of targeting temperatures of 50 degrees or lower, which immobilizes insects and slowly reduces the population size,” said Weaver. “This approach works very well if you have a level grain surface and an adequate airspace. Limited space and temperature gradients will cause unwanted and problematic condensation even when using moving air to cool the grain bulk.”
Unusual weather can lead to a variety of discounts that cannot be controlled because they occur before harvest. Examples are test weight or kernel size.
“However, keep in mind that careful storage can help to reduce further losses. It is always important to remember that the longer grain is stored, the greater the probability of the loss of quality. This is simply the nature of storage, so the best plan is to optimize quality preservation with a reasonable target date for delivery in mind,” Weaver concluded.
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