A truism about grain storage learning is that each trial, experiment or learning event requires a year. This suggests that progress on what really works takes a long time. Added to the length of a cycle for storage is the variability of climate, weather, crop conditions, operator follow through, the applied method and differences in seeds at a biological level. Good conclusions require getting the correct balance among these factors.

An Iowa farm boy saw many advances as he grew up but wondered why too often grain spoils and the result is that livestock and turkeys do poorly and even die after eating moldy grain. In 1974 an experiment led him to what turned out to be a better way.

TGM founder Dan Kallestad grew up on a farm near the small town of Rake, Iowa, a mile from the Minnesota border. Crops included corn; soybeans; oats as a nurse crop and for straw for bedding; and alfalfa/bromegrass pasture and hayland. Livestock included feeder cattle, feeder pigs, 3,500 turkeys (free range in the '50s) and a beef cow/calf operation for awhile.

Dan left the farm, but returned in 1974 due to circumstances including the death of his father. Many changes were occurring at the time and the trend was toward high heat drying of corn as opposed to letting corn finish its cycle in a corncrib, relying on the wind to dry it. Handling corn on the cob had become too labor intensive but, in Dan's mind the high heat drying methods were damaging the value of the crop. He thought there must be a better way.

His investigations led him to what was called 'natural air drying'. Many claims were made for and against this method but little scientific evidence existed. So the story starts:

1974 Experiments on Iowa farm.

A 36' natural air drying bin was installed for the 1974 corn crop. Records were maintained on each load put into the bin and of course of what was delivered. Each load was weighed, the temperature was checked and a moisture sample was taken. This was recorded as the wagon was unloaded. Test weight was determined by saving a sample from each load and periodically taking it to the elevator for measurement. Electric meters were installed to record energy use.

The following year at delivery the old-timer trucker who had retired from corn shelling remarked as he ran his fingers through the corn as the truck was being filled "I haven't hauled corn this nice for many years". Most had abandoned cribbing corn and were using high heat dryers of some sort or another.

In 1975 two bins were sold to other farmers to continue the evaluation. With good outcomes a business grew that sold over 600 systems before the great farm price collapse in the early eighties.

One of the outcomes was that there was considerably less shrink than the pencil shrink used by elevators. (Current work looks promising to provide reliable comparisons on shrink factors and how to benefit from this.)

1979 Experiments with profiles during grain curing.

An experiment and test was designed to find out how natural air drying (curing) progresses within a grain bin. A new 30' diameter grain bin had 5' horizontal probes installed up the sidewall — each 12" above the next lower one (a junction box was on the exterior, a grommet protected the 1" ID hollow fiberglass tube that protruded 5' toward the center). Each was equipped with a temperature and relative humidity sensor at the end. A data logger was connected so the readings could be saved automatically.

This experiment seems to not have been repeated any where in the world. [And no, the probes were not pulled down when the bin was unloaded from the center dump, but remained horizontal — reaching into the air.] The probes were mounted horizontally because air channels around a cable hanging vertically so the corn right next to the cable will change several times faster than that several feet away. During initial drying this can be misleading, especially when handling wetter grain. As aeration continues the differences diminish.

1983 First Sentry PAC introduced.