Effects of Subsoil Compaction on Corn Yields

ABSTRACT SOIL compactilon has been recognized for several years as having a detrimental effect on plant growth. Since tillage generally loosens the soil in the plowed layer, it was hypothesized that perhaps much of the compaction problem was in the subsoil layer. This compacted layer is often referred to as a plow pan. During the winter of 1979-80 experiments were carried out both in the field and in the laboratory to determine the effect of freeze-thaw cycling on compacted layers. The effects of cycle duration, initial soil moisture, and free water availability were noted. The indications are that the cumulative effects of sub-soil compaction in Indiana can severely reduce corn growth, vigor, and yield. The natural forces of freezing and thawing do not appear to be reliable agents of pan breakup.