Monday, April 27, 2015

Looking Ahead: Expect to See Sidewall Compaction

Chad Lee and Carrie Knott, Extension Agronomists, University of Kentucky

Figure 1. Open seed furrow is a good indicator
of sidewall compaction.
The calendar says we are getting late on planting corn. While the soil conditions are probably more important than planting date, there will be intense pressure on producers to plant corn this week. That means that some fields will likely get planted too wet. Getting into a field too soon is completely understandable given the logistics of planting multiple fields and trying to "sneak in" a field between rains.

If going into a field that is too wet, back off the down pressure and the closing wheel pressure. In addition, hope for some larger quantity of rains shortly after planting and before the soils dry. If the soils dry out immediately after a field was planted too wet, then sidewall compaction probably will occur in that field. Images of both sidewall compaction and surface compaction are included here to help you identify the problem about a month after planting.

Another common sign of compaction is nutrient deficiencies. Nutrient deficiencies develop because the root system has been limited within the compacted areas. Those confined roots can rapidly deplete nutrients in that area. Images of potassium deficient corn are below. Although tempting, foliar fertilization will not rescue the stands because the needs far exceed what can be applied economically in a foliar form.

Once compaction has occurred, whether sidewall or surface, there are no solutions for this season. The damage is done.

Figure 2. Corn roots confined to the seed furrow.
Figure 3. Half-turn of the corn plant
reveals a "fan-like" shape to the roots.
Figure 4. The smeared edge to the seed furrow or
sidewall is a good indicator of sidewall compaction.
Figure 5. Sidewall compaction is one of many
things that can cause stunted plants.

Figure 6. Plants are stunted and potassium deficient from a
combination of surface compaction and sidewall compaction.
This field had a manure history and high soil test for potassium.

Figure 7. Roots stunted from surface compaction
that was created the previous fall
when harvesting a wet field.
Figure 8. High traffic edge of field lead to surface compaction
that lead to potassium deficiency.


  1. What recommendations can you think of given the actual wet soils?

  2. The best thing is to wait one more day. We usually cause the most problems by getting into the field one day too early. Given the late season and the pressure to get started, I expect almost no one to follow this! So, if a farmer wants to push into a field anyhow, then the next option is to back off the down pressure and closing wheel pressure. Spader or spike-tooth closing wheels can help some, but I've seen sidewall compaction and divets from the spikes in a field before. So, they have their limits as well. When getting into a field too early with a planter with central seed tanks, I would expect those units to have more surface compaction directly under the seed tanks. Getting into a field one day too early with any equipment (fertilizer spreader, sprayer, or planter) can result in surface compaction directly under the tire path. This would be a good season to have a controlled traffic system.


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