A farmer asked Jeff Phillips if one-half inch was too shallow for soybeans. Phillips is the Extension ag educator in Tippecanoe County. This was just last week, on April 22. Phillips first reaction was to think about weather.
"They're predicting rain, so they should come up even if they're shallow," he says. In the end, the farmer decided to drop his planter setting half a notch to increase the depth slightly. He was no-tilling into stalks, and although the ground wasn't rutted, it was hard, particularly where combine tires ran last fall on moist soils. Even using a planter and not a drill, depth placement when no-tilling into stalk residue can be somewhat inconsistent.
Seed depth remains one of the most worrisome decisions a farmer must make in the field. Computers can vary seeding rates, even switch where fertilizer materials are applied, but so far, there isn't a computer program that selects the perfect seeding depth based upon input, such as soil moisture percentage and soil temperature. Such a program would likely also want to factor in field conditions and expected weather within the next 34 to 72 hours. The weather can have an effect in two ways- both temperature and rainfall.
Part of the problem is locating the seed to check depth, especially if it's not treated and doesn't stand out with a bright color in the soil. One central Indiana farmer has perfected a method which usually works. Instead of picking with a knife until he finds seed, he takes a thin, short board and gradually rakes off a thin layer over the row at a time, like removing the layers from an onion. That way, the typically sees the seed and gets an exact indication of its depth before he disturbs it in any way.
Monitors mounted in the cab area are great for sensing seed populations, but they don't help sense depth. Seed depth is still a get-out-and-look procedure. Add-ons such as Keeton seed firmers help make placement more precise, but there is still no good way to determine seed placement without physically checking.
If there are ag engineers out there reading, maybe someone would like to tackle a sensor that senses and reports seed depth. Or if there is one out there, let us know. It's an area where technology could pay dividends.