Altered Corn Emergence – Compaction/Crusting Issues

I don’t have to tell any of you the amount of rainfall we have had over the last several weeks. Most of the rainfall we have receiving has been high intensity rainfall (i.e. all coming down at once). High intensity rainfall followed by warm windy days can lead to significant soil compaction and crusting issues on some of the soil textures we have in the Delta.

Compacted Corn Seedling. (Photo Courtesy of Tom Eubank)

Over the last several days we have received phone calls about poor or uneven corn emergence in some corn fields in the Delta that were planted prior to the rainfall events we have encountered over the last several weeks. In one instance, Dr. Tom Eubank called describing corn seedling symptoms that appeared to be caused by compaction. In general, when a corn seedling begins to emerge, elongation of the mesocotyl allows the corn to “Spike through the surface”. In instances when the Mesocotyl cannot move north or is impeded by a soil physical characteristic from upward movement, the below ground corn seedling may wrap around itself looking for a way up. As the corn seedling winds around itself and spends energy trying to get to the soil surface, the below ground seedling may exert a leaf underground that often sticks as it tries to un-whorl, this scenario generally leads to seedling death. The predominate cause in the situation pictured is due to soil crusting compaction and possibly sidewall compaction at the time of planting. Keep in mind that silt content of a soil influences the compaction. So for the Delta, this means that “Mixed ground” will have the probability to experience this issue more frequently than our “Sandy” or “Buckshot” soils. For more information on corn emergence from Purdue University see http://www.kingcorn.org/news/timeless/Emergence.html