The ability to meet "T" requirements for conservation plans depends upon numerous factors including slope, soil type, location, amount and kind of crop residue, and the amount of soil disturbance from the tillage system. When harvesting corn silage most crop residue is removed from a field making it difficult to maintain T.

In the 25 April 2002 issue of the Wisconsin Crop Manager, I suggested one way to make T requirements is to raise the cutter bar on the corn silage chopper. Raising the cutter bar 24 inches would leave about 2 Tons/A of residue and 32 to 83 percent soil cover thereby meeting the T requirement. This strategy lowers silage yield, but a trade-off exists whereby silage quality is increased. Thus milk per acre is lowered somewhat, but not as far as one would think because the lowest quality part of the plant remains in the field as residue and can contribute to ground cover.

If yield is a concern, an operator could adjust the cutter bar as harvest progresses across a field. Not all parts of a field need to have the cutter bar set to one position. Level areas could be cut with the cutter bar in a normal lower position, while in sloped parts of the field the cutter bar could be raised leaving more residue. This strategy is relatively risk free to the farmer compared to other approaches such as cover crops, etc. The only requirement is some diligence and field awareness during chopping.