Thinking about rolling soybeans?
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EmailUsing land rollers in soybean production has advantages and disadvantages. Here are recommendations for reducing the adverse conditions created by land rolling.
Every winter during the Michigan Soybean On-Farm Research Update regional meetings, several farmers ask about rolling soybeans, question whether Michigan State University and MSU Extension have conducted research on the practice, or suggest we include this as a research topic for the coming season. What is this practice, what are the potential benefits and cautions, and what has research shown?
The use of land rollers for soybean production has increased in Michigan. The practice involves pulling weighted drums across a field to level the surface and push rocks downward that have been brought to the surface due to previous tillage passes or frost heave. Downward pressure needed to push down rocks is roughly 3 psi or 450 to 530 lbs. per foot of roller width. The main benefit realized by rolling soybean ground is improved conditions for field operations. Rolling pushes stones into the soil and crushes soil clods and corn root balls.
Farmers comment on how much smoother planting and harvesting are with rolled fields. Rolling also reduces the potential for combine damage from rocks that are struck by the cutter bar or make their way into the header or combine. There is a potential for reduced yield loss (fewer pods missed as the cutter bar is able to ride closer to the ground) particularly with lower plant populations when pods tend to set lower on the plants. Other benefits of rolling include less combine operator fatigue, slightly faster groundspeeds and less soil contamination of the harvested seed (an important consideration for seed producers).
However, rolling has not affected soybean yield in numerous research trials conducted in Iowa, Minnesota and North Dakota. A study conducted by University of Minnesota Extension from 2008–2010 with rolling at five different timings (pre-plant to V3) plus a non-rolled check found no significant differences in stand, yield or seed quality. A study in Ontario showed a slight advantage of rolling at V1 compared with the control. A 2012 trial conducted by Michigan State University Extension and the Michigan Soybean Checkoff program produced similar results with rolling prior to emergence.
Rolling soybeans was investigated in the Michigan Soybean On-Farm Research Program from 2016-2018 at 17 locations. Most sites were rolled at V1 but two sites had three timings (Pre, V1 and V3). No differences were found in yield at the multi-timing site but stand was reduced at V3 at one location. Yield was significantly increased at two sites and decreased at one with rolling at V1, but no differences were detected at the remaining sites. Stand was reduced at those sites by approximately 5,000 plants/ac with rolling, but average yield was not different compared with the control.
The disadvantages of land-rolling include: higher production costs, potential plant damage, increased soil erosion and reduced water infiltration. Soybean injury increases significantly around V3, with damage from tire tracks being even worse than from the rollers. However, soybeans at the “hook” stage (when the hypocotyl and cotyledons form an arch above the soil surface) are also very susceptible to breakage. If soils are wet when rolling, surface pores can be sealed leading to crusting and reduced infiltration of rainfall, especially in finer textured soils, and the risk of runoff increases on sloped fields.
Some of these adverse conditions can be mitigated by careful and judicious use of land rollers. The following recommendations were extracted from the University of Minnesota Extension publication “Management Considerations for Rolling Soybean in the Upper Midwest.”
- Restrict rolling operations to rocky and flat fields.
- Roll emerged soybeans as early as possible, but before the V3 growth stage.
- Roll emerged plants during the heat of the day when plants are limp to reduce plant injury.
- Roll erosion-prone fields after the plants reach the V1 growth stage.
- Avoid rolling when the plants are wet as they will stick to the drums and be pulled from the soil.
- Avoid rolling when the soil is moist to reduce the potential for soil sealing and reducing infiltration rates, especially on fine-textured soils.
