Ron,

Yes heavy grain carts on tires can cause enormous amounts of compaction. At a meeting in ND an agronomist from the U of MN said that grain carts on tires running through the fields are the single worst source of compaction. That compaction can go 20" deep or more, as I recall at the meeting. Combines with full grain tanks are close behind.

Both can cause problems in strip till as well as any other tillage system. In the picture below we are making strips in the fall in bean stubble near Frankfort, Indiana in heavy clay soil. The customer said it was "pretty wet" when they harvested these beans. This was with the largest combine Case makes. We had to work at it but could make strips in these tracks as you can see.

In corn residue, the combine can be set to run on the just harvested row. This helps in two ways:

 1) the combine is running on top of cornstalks which significantly reduce compaction.

 2) by running the combine on the just harvested row that means it will be 2 seasons before corn is again planted in the path of the combine tires.

Unfortunately IF the grain cart is run in the field for unload on the go there are two more rows of max compaction. It's better if you can keep the cart tractor and the cart it self on the just harvested stalk rows but that is probably not likely to happen consistently. 

The best thing to do is to unload into the cart at the end of the field/headlands. The headlands can be ripped if necessary or just limit the problem area to the headlands. Depending on field size some customers put a cart path across all rows in the middle of the field. The cart stays in the cart path with the combine stopping to unload as it goes by that path. Sorry if I am not clear.

The combine compaction can not be eliminated so it is best to control where it occurs. The grain cart compaction can be controlled by controlling and planning cart traffic patterns. Keep the compaction out of the middles where next years corn on corn crop will be planted. Grain cart compaction is the worst. Normal tillage doesn't really get to the full depth of it. jmho.

 Note the strip on the right side running in the combine tire track in wet clay. Not bad. Fall strips in WC Indiana. I don't think there were carts in this field from the looks of it or thee would be even MORE compacted tire tracks. I spoke with this customer last week at the FPS. He said the corn planted into these strips this spring looks very good. "similar to worked ground corn in the area" If yields are even close, his strip till will be more profitable due to much lower costs to put crop in and fertilize it. Look at the size/modest hp of the tractor pulling this 16 row.

The next piece of equipment in the field is the planter. The strip till yield could probably even be slightly lower and STILL be more profitable. 0.3-0.4 gal of diesel per acre rather than 4.0 or more. I think the economics are worth controlling the grain cart traffic somewhat. I know, "it can't be done"....Sorry to wander.

 Jim at Dawn

(Dawn 7940 16R30 Strip Till in bean stubble dsc0723.JPG)

Dawn 7940 16R30 Strip Till in bean stubble dsc0723.JPG (91KB - 195 downloads)