No one would tell you that if soil compaction wasn't an issue, your corn yields would be 50 bushels better this year. But some might make what seems like a fair statement- soil compaction added to rooting issues for corn.
Soil compaction always causes more impact in a dry year. When a year is this dry and hot, other factors may overshadow it. But a wet year would mask the effects of soil compaction. That's because one of its primary impacts is to affect rooting and the search for moisture. Gary Steinhardt, Purdue University Extension soil specialist, proved this in the 1980's.
You will find soil compaction patterns even in fields where you thought you didn't work ground wet this spring. Look for them on end rows which received lots of traffic. However, Tony Vyn, also a Purdue University agronomist, believes that the effects of soil compaction that worked against this year's crop may have been caused before this year.
Vyn is a believer that the mild winter with lack of freeze and thaw cycles played a major role in setting corn fields up for the disaster that unfolded when it became hot and dry. He believes it limited soil recharge over the winter. And he also believes that since there were few freeze and thaw cycles, there was little or no breakdown of compacted layers in the soil that already existed from previous years.
Steinhardt says you can't count on freeze and thaw to eliminate soil compaction issues, especially if they are severe. Still, at the same time, parts of Indiana, especially the northern two-thirds, usually get some help in breaking down older compacted layers during the winter. Vyn is convinced that didn't happen this year.Soybeans are typically less affected by soil compaction. When Steinhardt did studies and showed yield reduction form compacted soils in corn, it was much tougher to do in soybeans.