Degradation of soil and water quality is not only a problem in the short term, but also has a long-term impact. Potential nutrient loss of phosphorous and nitrogen is also a concern, especially in the spring where a significant number of rain events and amounts are received in the Midwest region. In order to reduce surface runoff, conservation practices that reduce soil compaction (i.e., maintaining an intact residue cover) are essential to protect our soil and sustain our water and environment quality. Regardless of the tillage system that the land roller will be used on, land rolling can destroy soil benefits associated with no-till or add additional damage if used on conventionally tilled ground, where intensive tillage has already destroyed soil structure.

The University of Minnesota researchers observed that land rolling may raise the risk of sealing the soil surface during rain events, which can lead to ponding, as was also found in Iowa. The consequences of reducing water infiltration into the soil profile increases the potential for surface runoff and loss of top soil and nutrients by erosion, thereby reducing crop productivity and yield. Also, compacted soil surface may lead to wet soil surface conditions that can have other effects, such as an increase in soil-born disease, especially in poorly drained soils, as found in a majority of Minnesota and northern Iowa fields. The Minnesota and Iowa findings confirmed earlier research by North Dakota State University (NDSU). Research in 2003 and 2004 from NDSU concluded that no yield loss from land rolling is observed, but injury levels go up if rolling was delayed until the first trifoliate stage, when plants are 3-4 in. tall.

Farmers’ desire to increase harvestability by pushing down rocks and corn root balls should be carefully balanced with the long-term effects of rolling on soil quality and water resources.  Potential effects on surface soil compaction as well as additional time, fuel and machinery cost of land rolling need to be considered since yield advantage or harvest loss from using this practice seems inconsistent at best. Earlier research shows that if the beans are standing well and the combine is properly adjusted, stubble cut loss is less than 1 bu./acre, and should be closer to ½ bu.

There are a lot of good alternative technologies to adjust and calibrate the combine correctly and manage residue and other farming challenges. If the issue is to remove rocks from the field, then this may not be the most efficient solution. Pushing rocks into the soil is a short-term solution, especially when fields will be tilled again the following season and the rocks brought back to the soil surface.

The bottom line is that while the use of a land roller may provide some comfort and “peace of mind,” and may reduce combine breakdown in some fields, it also carries risks and potential impacts to soil and water quality in the short as well as in the long-term.