The following information is a Web Extra from the pages of Farm Journal. It corresponds with the article "Dial in Down Pressure." You can find the article in Farm Journal's March 2012 issue.
Closing the Furrow
Soil texture and moisture determine how aggressive the closing system must be; not surprisingly, no-till requires a more aggressive system.
Rubber closing wheels work well in conventional tillage and coarse no-till soils, Ferrie says. Cast-iron wheels probably work in the widest range of conditions. Various types of spike wheels provide more aggressive action for tough no-till conditions.
You may want to mix and match closing wheels—for example, one solid wheel and one spike wheel—for your particular conditions. You may even want to keep two sets on hand, and change them as you switch between no-tilled and tilled seedbeds.
"Dragging a chain behind any type of closing wheels, to level the seedbed, is not a bad idea," Ferrie says. "Especially when used behind spike wheels, it can help fill in air pockets and prevent soil from drying out." A firming wheel behind each row can perform a similar function.
There’s no doubt different tillage conditions need different closing systems. As just one example from the Farm Journal study, spike wheels with a chain behind increased yield in no-till, but produced the poorest yield in a tilled soil environment.
The only way to check closing wheel performance is to dig behind your planter. Strive to place seed at the bottom of the trench, with soil firmed snugly (but not compacted), to keep it from drying out.