The main focus of the Indiana Prairie Farmer-Tippecanoe County Extension annual plot this year was to test how pressure or lack of pressure on row units affects seed placement and emergence.
Just in case there are differences that affect rooting and plant growth the test will be taken to harvest.
It's located at the Meigs Horticulture Farm, loosely associated with the Throckmorton Research Center south of Romney. This year a Precision Planting Air Force system was installed on the planter. When set on automatic control, it works to keep the pressure constant on all the row units. It does not control row units independently. That technology is being tested, but will be more expensive than the Air Force unit. Other companies also now offer active down force air pressure systems.
Precision Planting did not contribute to this plot, but the equipment to mount on the planter was obtained with grants in previous years form the company.
Four settings were tested: disabling the unit, a low pressure setting, a standard setting and a high setting. Once set, the unit works to maintain the desired amount of pressure on the row units by adjusting constantly across the field. An air compressor is mounted on the planter, and it produces the air pressure which feed into bags that fit on row units where springs used to be. On this particular Deere planter, the spring mechanism, which allowed for four manual "get off and change it" settings, were replaced with air bags on each row.
With the Air Force system all the settings can be changed from the cab, sometimes with only one or two pushes of a button.
Jeff Phillips, Tippecanoe County Extension ag educator, will be gauging emergence and taking sand counts to try to pick up differences that might be due to down force. The system has been looked at in corn, but more rarely in soybeans.