Spring 2009 presents many challenges for North Dakota crop producers.

“Most residues from the corn and soybean harvest are still standing and many cornfields remain ready to combine when conditions allow,” says Dave Franzen, North Dakota State University Extension Service soil science specialist. “The soil under the residue is saturated and, in some fields, deep ruts from October and November combining and field traffic remains.”

In fields with corn residue and no ruts, there are several options, including burning, multiple shallow tillage, spring strip-till or no-till.

No-till would be best suited in medium or lighter-texture soils (loams, sandy loams). No-till would not be as good an option for clay soils for corn and sugar beets due to the danger of the furrow opening up if the weather turns dry before germination and crop emergence.

Although the no-till corn and sugar beet yield was better than conventional tillage in a heavy clay soil in 2008, the year was exceedingly wet following emergence, so similar results would not be expected most years (http://www.sbreb.org/research/prod/prod08/prod08.htm). In drier years, no-till corn and sugar beet yields were significantly reduced compared with strip till or conventional till.

Heavy corn residue may delay soil warming and drying significantly this spring. Burning is therefore a consideration in these unusual conditions. It is important to contact the local authorities before burning to avoid unnecessary responses to bystander 911 calls or possible fines for not obtaining a permit in some areas.

The field will need a tillage pass around the perimeter to deter movement of the fire to neighboring fields. In addition, having a “buddy” nearby to help with fire containment may be important. Dry corn leaves may leave the field, so the fire will need to be monitored more than most grower experiences from burning small-grain residue fields.

“Burning will result in a loss of total nitrogen and sulfur from the residue, but may enhance available phosphorus and potassium supplies if the ash does not blow away before tillage,” Franzen says. “However, nitrogen and sulfur rates will not need to be increased this year due to burning. The actual nitrogen available for this year’s crop may actually increase because of the reduced residue that will be decomposed by microorganisms and the nitrogen they temporarily consume from the soil to accomplish decay.”

Tillage, whether following burning or without burning, should be as shallow as possible. No-till or spring strip-till planting also would be options following burning.

Another alternative to burning may be baling the residue if there are cattle nearby. However, on soft county roads, there may be a logistical problem moving the bales to the destination.

Some type of shallow “vertical tillage” probably would be best under wet soil conditions.

“It is not necessary in most of our soils to break up traffic pans,” says John Nowatzki, NDSU Extension agricultural machine systems specialist. “The wetness, future drying and our long winter with occasional thaws will help with that. The tillage will be needed mainly to break up whatever crust develops at the surface and allow better seed/soil contact and seal of the furrow so the furrow does not reopen when drying.”

A vertical tillage tool could be spike shanks; coulters set straight with the driving direction; a strip-till unit that does not use a straight, deep shank; a heavy rotary harrow; or, in lighter soils, even a long, thick-tine harrow. Heavy discs or wide field cultivator shanks may do more harm than good this spring, especially on heavy soils.

In fields with ruts, extreme patience will be required. These fields will need to be tilled deeper than fields without ruts to move soil into the ruts and fill them.

“To promote deeper drying if the fields become crusted, a shallow vertical tillage may be required,” Nowatzki says. “When the soil dries several inches deep, tilling the field at an angle to the ruts and pulling soil into the ruts first with a heavy disc and then with a field cultivator-type tool once residue is sufficiently cut may be a good option. A combination disc/field cultivator on a second pass might work as well.”

It may take several passes to fill in some ruts sufficiently. If possible, follow the same tractor tracks through each pass. Tractors with a RTK (auto-steer) system will be able to do this more effectively. Most compaction is made on the first pass, with lesser amounts added to the total compaction in future passes, so limiting and controlling traffic passes is important whenever possible and practical.

No-till soybeans into corn residue has been conducted successfully for more than twenty years in the Corn Belt. Visit with your local equipment dealer to see if you are set up with the appropriate seeder.

“With the current suite of pesticides (volunteer corn will be a problem in most standing residue fields), no-till soybeans is particularly easy to do,” Franzen says. “Going into standing stalks the first time without tillage may seem crazy, but the results have been overwhelmingly positive through the years. In campus research on no-till in heavy soils, soybeans have been the most resilient to no-till, probably because of their ability to fill in gaps in stand with little yield loss.”

No-till corn into soybean residue also has been used successfully, but not as successfully in heavy soils. Some shallow tillage still is recommended in soybean stubble in heavy soils to prevent the furrow from reopening.

NDSU Agriculture Communication