Everyone knows the importance of getting good seed-to-soil contact. The best way to achieve this is to have proper down pressure. Kevin Kimberley, a crop consultant in Iowa, explains the best ways to get your down pressure set properly before going into the field.
The parallel linkage bolts to an angle iron. The width for the angle iron should be the same at the top and bottom where it bolts to the frame of the planter.
Wear in the bushing or loose bolts increases the chatter in your row unit, which also increases the play in your parallel linkage. Worn bushings cause unit not to run level, which increases seed bounce.
With many of the older models, Kimberley suggests taking hold of the back of the row unit and moving it from side to side, up and down to check to see if the bushings are tight.
“This is a major piece to the puzzle. If you plant through waterways, you need to be careful because the row unit can get twisted and it will go through the field cockeyed,” states Kimberley.
If you run through waterways the shank or parallel linkage can be bent. They can be straightened but sometimes they have to be replaced.
You can usually get by with replacing the bushing or switching to a larger bushing, if it isn't tight. If it is really bad, Kimberley says to replace the whole parallel arm.
The parallel arms can also wear. Check the bushings, bolts, and elongated holes. Worn parts can cause the row unit to operate in an unbalanced manner, affecting seed placement, closing wheel spring pressure, and row-unit spring pressure.
The parallel linkage should be checked regularly. If you have been planting for several days and have a rain day, check them again.
There are several factors that affect the way planters work in the field. From soil type to tillage system and soil moisture to planting equipment, each field might require a change in down pressure. As you go from field to field, check your depth wheels again to ensure accurate pressure in each field.
There are two systems that are used: the ever-growing popular air bags and the traditional springs.
When using springs, Kimberley says to check to ensure all the springs have the same tension. Some springs will slide up and down on the parallel linkage. This causes the springs to stretch, and it will wear one side of your parallel linkage and cause it to bind.
Kimberley advises his customers to get air bags over springs because they get more constant pressure. “Before you go into the field, pump the air bags up with soapy water to make sure you don't have any leaks,” he suggests.
To check down pressure, stop with the planter in the ground. Where the true vee is, see if you can break the sidewall down with your finger about ¾ of an inch out of the edge. Another way to check is to see if dirt is falling in your trench. If so, you don't have enough down pressure. Another option for some is to turn the depth gauge wheel. If it spins freely there isn't enough down pressure. If you can't move it at all, then there is too much pressure. The gauge wheel should press on the soil, but you should be able to turn it.