You have been able to adjust down force pressure on row units on most planters for a long time. However, for many years it wasn't an easy adjustment. Many planters used coil springs, and selecting one of three or four possible settings had to be done by hand.
Precision Planting changed that when they introduced the Air Force system a few years ago. It uses compressed air and air bags on each unit to control down force. Other companies have introduced systems since then.
Now, Precision Planting has introduced Delta Force, which adjusts down force row by row with hydraulic cylinders instead of air bags. It is a more costly system.
Beck's Hybrids has tested down force for the past five years at their practical farm research location in central Illinois. They tested the Delta Force system for the first time in 2013.
Compared to letting Air Force determine the proper rate in a variable rate system across the field, no down pressure has averaged nearly 12 fewer bushels per acre over the five-year period. Setting the unit to maintain 125 pounds of pressure has produced about 4 fewer bushels on average, but was actually slightly better than variable control last year. When the force is set manually at 250 or 375 pounds of pressure, yields fall drastically, by nearly 7 and 10 bushels per acre respectively over the average of the five-year period. Too much pressure creates sidewall compaction if the soil is not perfectly dry.
In its first year of testing, Delta Force appeared to show returns over the Air Force system in its variable rate position, which was the control for the test. However, Jason Webster, who heads up the research there, believes more testing is needed. He intends to take another look at down force trials, including the new Delta Force option, this season.