While harvest is in full swing and attention is focused most intensely on the yield monitor, soil considerations are important even if they are just below the horizon. Avoiding or reducing soil compaction is important with all of the potential traffic across your fields during harvest operations. Keep in mind that a full combine or grain cart can have an axle load near 40 tons and can create soil compaction 30-36 inches into the profile.
The best management practice to reduce compaction is to use the same wheel tracks when making additional passes across a field. Under the best conditions, more than 80 percent of compaction damage is done on the first pass across the field so limit that damage to the fewest number of wheel tracks when possible. Avoid angular traffic or “shortest path” traffic, as well. While it might save you a few moments of time, the potential damage to your soil and future yields can have an even greater value.
Perhaps you already have your fall tillage scheme laid out and the plan you have is proven to work well on your individual field soils. If there are remaining considerations concerning if, when or how deep to till, think about what equipment you have and how much time you usually have for fall tillage. Deep tillage with a moldboard plow or disk ripper may require more horsepower and time whereas shallow tillage can often be done at higher field speed and leaves more residue on the surface as well.
While the thought of completely black fields still appeals to many, consider both the volume of residue you need to manage, the timing of planting (earlier vs later planted crops next spring) and influence fall tillage has on spring soil warm-up. Identify the planned crop for each field next year, the volume of residue the current crop has produced and whether timing of planting will allow reduced or shallow tillage with a manageable delay in soil warmup for your anticipated spring planting dates. In terms of tillage speed, remember that no tillage in the fall is the fastest fall operation if residue load, planting date and next year’s crop allow it, but use the least disturbance possible where it applies.
Last spring, several areas of the state endured large volume spring rains resulting in drowned out crops and some field erosion ranging from sheet erosion all the way to gully erosion (deeper than 12 inches). While traveling from a meeting this past week, I passed some land where the deep gully erosion from spring events had been moldboard plowed shut after harvest in preparation for fall tillage to occur. If your fields have gully erosion that must receive work before fall tillage operations, it might be a good time to consider planting permanent cover on those eroded waterways.
This fall before major tillage operations, take a look at any erosion your fields had this year and consider in those cases of severe rill or gully erosion that a permanent grassed waterway or perhaps even a sedimentation structure might be advisable to slow surface water movement across the field. Your land is your greatest asset and keeping it as your land retains that resource for years and generations to come.
Dr. Paul Meints is the Director of Research at Minnesota Soybean and has an MS in plant breeding and genetics and a PhD in Seed Physiology.