High Axle Load Compaction and Corn Yield

AN experiment was set up to study the effect of high axle loads on subsoil compaction and corn production in two soil textures. Treatments of 10 and 20 t/axle were applied at two soil moisture contents. Resulting changes in soil physical characteristics as compared to a control were measured to a depth of 0.60 m. Topsoil and subsoil dry density levels were significantly increased by high axle loads. Moldboard plowing of compacted plots to a depth of 0.20 m did not fully relieve topsoil compaction. Because of the small difference between them, the two soil moisture contents at the time of compaction had little effect on topsoil or subsoil bulk density in either field. The incurred soil structural changes had minimal effect on the growth and maturity of grain corn in the loam field. However, yields were significantly decreased by compactive loading. Both moisture and compaction treatments significantly modified the rate of plant growth, maturity and yields in the clay field...