What we wouldn’t give for extra hours at harvest. If you could be out there, in the field, seven to 10 days earlier than you typically would, how often would you get caught with a crop you couldn’t take off?
Those farmers who have natural air drying in their bins tell me when the wheat is 18 or 20% moisture content, they don’t even think about it — they harvest.
If you’re set up for natural air drying, you can be in the field seven to 10 days earlier than you normally would. You can start combining when that wheat is at 20% moisture content.
I still find there’s some confusion about aeration versus natural air drying. Aeration is grain conditioning or cooling in a bin, which requires a low airflow rate of only one-tenth of a CFM per bushel moving through the grain versus natural air drying, which requires three-quarters to one CFM per bushel.
Sometimes harvesting early means the temperature can be 85 F outside and the grain going into the bin is smoking hot and this is when being able to aerate the bin is so important as hot grain in a bin with no air flow increases the risk of grain spoilage. Having temperature cables in the bin is also a great idea because you can tell when the bin is cooled down and do not have to be running the aeration fans any longer than necessary.
Another benefit of aeration in every bin is once the grain is cooled down, the risk of bug infestations is greatly decreased. There’s nothing bugs love more than a bin of hot, humid grain in which they can thrive.
If you have a 5 hp FC fan on your 4,000-bu. hopper bin for natural air drying, you are truly in control. For example, at the beginning of September you can combine wheat at 20% moisture content and dry it down in five to seven days to get a jump on harvest. If the grain starts coming off dry later, but hot, you can simply cool the grain down in one to two days to prevent spoilage.
Nothing happens in the bin the first day of natural air drying, as it takes the better part of a day for the grain to equalize out both in temperature and pressure inside the bin. After that, with ideal drying conditions, you can dry around 3/4 to 1 percentage point per day.
As temperatures cool in the latter part of September or early October, the air’s capacity to dry is reduced. There may be warm, dry days, but the evenings are cool, thus the grain dries only around 1/4 to 1/2 a point per day, so then it will take around 10 to 12 days to dry that grain down.
There’s a point between mid-October and mid-November where we transition from fall to winter conditions. At that point, grain won’t dry in a bin as natural air drying will not work below 50 F. The only option is to go with some low temperature heaters which can sometimes gain you a couple more weeks of slow drying, or freeze the grain up in the bin and dry it down in the spring.
If you’re set up for aeration, maintaining the integrity and quality of your product is easy. With natural air drying you could also be buying yourself 10 days at harvest — what could be better than that?