Drying Beans? Know The Temp, Humidity And Equilibrium Moisture

Fields are wet in central Illinois, harvest is delayed and soybean quality is suffering. The combination means farmers will need to start pushing to get the crop out of the field, even though conditions are unfavorable.

Find out now what the dockage is at your point of delivery, Ken Ferrie advises.

“Early in the harvest, elevators weren't taking wet beans,” says Ferrie. “The word now is that some are taking up to 18% moisture beans. Know what that dockage is and prepare your landowners and farm managers for it.”

Farmers have been calling Ferrie to ask about putting soybeans in the bin and adding air and/or heat to them. He says if you have open bins with good air capacity, this is a good option.

“You'll have to monitor your air temperature and outside humidity to know what that soybean equilibrium moisture is,” he cautions. He provides two examples for consideration. Example 1 explains a scenario that doesn’t work, while example 2 is plausible and effective.

Example 1
On Thursday, Ferrie says the weather report showed 52 degrees °F and 90% humidity, making the soybean equilibrium moisture 19.4%.

“The only way you could have dried beans yesterday with air would have been if the beans were 20%. But if they were below 19.4%, adding air into that situation would have raised the temperature,” he says. “If you had turned the fan on and tried to pull down 17% moisture, it would have gone up instead of down and possibly could have caused structural issues to the bin once those beans expanded.”

Example 2
On Friday, Ferrie says the weather report showed 53 degrees °F and 60% humidity, putting the soybean equilibrium moisture at 11.2%.

“Today is a bean-drying day,” he says. “If you can add a low amount of heat, you could dry those wet beans on those wet days. Keeping the heat low is a necessity to keep you from burning the beans and causing splits,” he adds.

Ferrie says it’s important to set up your bin with 2 CFM of airflow per bushel of grain. You will need to use a bin with a full aeration floor. Two cubic feet per minute of airflow per bushel of grain is recommended for natural air drying. As a rule of thumb, most fans produce about 1000 CFM per 1 horsepower, but this depends on fan type – contact your fan supplier for detailed charts. If your fan is too small, increase the “effective” airflow by putting fewer bushels in the bin.

Because soil conditions are wet, evaluate your flotation on harvest equipment. The more flotation now, the better.

“In falls like this where the more things are on tracks, the better off you are,” Ferrie says. “For no-tillers, remember these lug tracks are next year’s seedbed.”

He offers two recommendations:

1.    If you have floatation on the grain cart and not the combine, keep the combine light and unload more often.

2.    If you have flotation on the combine and not the grain cart, dump on the ends.

The fields you track up this fall may need some vertical tillage in the spring to get a good seed bed, Ferrie notes. Fields with ruts are going to need more aggressive tillage between now and planting.

“Let's keep track of these fields as we finish up harvest, so we know what our plan of attack is for each of these fields going forward,” he says. “Putting in tracks or ruts combining corn going to no-till beans next year is a little more forgiving. Beans don't usually respond to tillage, and you can go in and fix ruts and tracks without much detriment to yield.”

However, ruts in bean fields going to no-till corn next year will need to be fixed or corn yields will suffer.

“That means we'll have to pull them out of no-till, fix this year's damage and then go back into no-till,” Ferrie says.