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Published June 12, 2010, 12:00 AM

Moisture, temperature important factors in summer grain storage

Producers planning on grain storage this summer should factor in the temperature, moisture content and quality of the grain, a North Dakota State University engineer said.

Producers planning on grain storage this summer should factor in the temperature, moisture content and quality of the grain, a North Dakota State University engineer said.

Grain moisture content must decrease as grain temperature increases for proper storage, said Ken Hellevang, agricultural engineer with North Dakota State University Extension Service.

For example, the allowable storage time of 15 percent moisture corn is about nine months at 60 degrees, five months at 70 degrees and only three months at 80 degrees.

“Grain with mechanical damage is more susceptible to mold growth and has a shorter allowable storage life than undamaged grain,” Hellevang says. “Corn harvested at moisture contents of 25 percent and higher likely has a higher than normal amount of mechanical damage and will have a shorter allowable storage life than corn with limited mechanical damage.”

Keeping grain cool and dry during the summer months is key, said Paul Lautenschlager, general manager of Beach Cooperative Grain Company.

“We live in a dry climate, and the humidity is rarely like it is now,” Lautenschlager said Friday. “If you put fans on it, you’re going to be in good shape.”

The co-op hasn’t had much issue with keeping grain in condition, he said.

“If you’ve got air and fans, you’re fine in this part of the woods,” Lautenschlager said. “If it stays (humid) like this for four or five years, we’ll have to change.”

Mold growth and insect infestations occur rapidly at summer temperatures, so stored grain should be checked every two weeks. An insect infestation can go from only a few insects to a major infestation in less than a month, Hellevang said.

He recommends measuring the stored grain temperature at several locations near the top surface, along the walls and several feet into the grain.

“Temperature sensors are an excellent tool, but remember that they only measure the temperature of the grain next to the sensor,” Hellevang says.

The recommended long-term grain storage moisture content normally is associated with the equilibrium moisture content for the grain at a relative humidity of about 65 percent to limit mold growth at summer storage temperatures.

According to NDSU Extension information: The EMC at 80 degrees and 65 percent relative humidity is about 13.5 percent for wheat, 12.2 percent for barley, 13.1 percent for corn, 11.2 percent for soybeans, 7.6 percent for oil sunflowers and 9.9 percent for confectionary or sunflowers. These EMCs correspond to the general recommended long-term storage moisture contents of 13.5 percent for wheat and corn, 12 percent for barley, 11 percent for soybeans, 8 percent for oil sunflowers and 10 percent for confectionary sunflowers.

“The goal for summer storage should be to keep the grain as cool as possible to limit insect activity and reduce the potential for mold growth,” Hellevang says. “Insect reproduction is reduced at temperatures below about 65 to 70 degrees.”

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