NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

February 18, 1999

Grain Storage Management Action May Be Required

Insects and moisture continue to pose a threat to stored grain in the region, according to North Dakota State University specialists. That means producers need to monitor grain condition now and take appropriate action to protect it before warmer spring temperatures arrive.

"We had more grain go into storage than normal, with some of our grain stored in facilities and under conditions that are less than ideal," notes Ken Hellevang, an agricultural engineer with the NDSU Extension Service. "Some of that grain, especially row crops, also went into storage with higher moisture levels than we'd like to see." Insect infestations were common in late fall and early winter and moisture problems, including ice on the grain surface, have been reported recently.

The temperature of stored grain should be taken at several locations, Hellevang says. The recommended temperature for winter storage is 20 F to 30 F. For spring and summer storage, grain temperature should not exceed 40 F. Warmer temperatures increase the potential for insect and mold problems. Hellevang advises checking stored grain now and periodically in the future depending on the condition of the grain.

Check the grain moisture content at several locations also. Unless your moisture meter automatically measures the grain temperature and adjusts the reading, a temperature adjustment for cold grain must be made, Hellevang says. For the most accurate moisture test, place grain samples in sealed bags and allow them to warm to room temperature before measuring the moisture content. Warm samples may also be checked for insects because insect activity increases at warmer temperatures.

Grain that exceeds recommended storage moisture contents must be dried before the grain warms. Remember that grain near the top of a bin may be warmer than outside air temperatures due to solar heating of the bin roof. Grain will also be warmed by warm moist air being blown into bins through uncovered fans and ducts. Fans and ducts should be covered when fans are not operating.

The allowable storage time is reduced by about one-half for each 10 F that the grain is warmed. For example 20 percent moisture corn has an expected allowable storage time of about 300 days at 30 F but only about 65 days at 50 F.

"A very small amount of drying, such as a few inches of damp grain at the top of a bin, can be accomplished with an aeration system, but generally drying requires a large drying fan or removing the grain and drying it in a high temperature dryer," Hellevang says.

Natural air and low temperature drying should be started when outside temperatures average about 40 Ftypically in early April. At colder temperatures, the drying rate is slow and inefficient. Soybeans with moisture contents up to 16 to 17 percent can be dried to about 13 percent moisture in April using a natural air drying system with an airflow rate of 1.0 tp 1.25 cubic feet per minute per bushel. Corn with moisture contents up to 20 percent can be dried to about 15 percent in April and 13 percent in May using an airflow rate of 1.25 cubic feet per minute per bushel. Air temperatures should be less than 130 F to minimize splitting.

Hellevang also cautions producers to remember that soybeans are more likely to be damaged during handling when they are cold. Soybeans should be warmed to 30-40 F prior to handling if they were cooled to very cold temperatures for winter storage. If augers are used they should be operated full and at slow speeds and drop heights should be minimized.

Once warmer spring temperatures arrive, stored grain will begin to warm and storage problems will worsen rapidly, Hellevang notes. Mold will begin to form and insects that had gone dormant over the winter will become active.

"We'll begin seeing insect activity when the grain reaches about 50 F," Hellevang says. "If those problems are severe, we'll need to consider some kind of fumigation to control those pests. Unfortunately, we can't get effective fumigation results until the grain gets up to around 60 F."

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Source: Ken Hellevang (701) 231-7243

Editor: Tom Jirik (701) 231-9629