Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 17, 1996
Publication Date: N/A
Technical Abstract: There are about 4 million hectares of claypan soils in MO and IL which have a subsoil horizon with 50-60% clay. Erosion has caused significant losses of topsoil leading to reduced infiltration. To gain insights into how differences in long-term cropping and management practices have influenced soil properties, a study was conducted in Sept 1995. Samples were collected dfrom sites in native prairie vegetation, 50-year Eastern Gamagrass (EG), soybean following 50-year Eastern Gamagrass, and a long-term corn-soybean rotation. Infiltration rates of the surface and claypan horizons were measured in the field using a double-ring infiltration device. Saturated hydraulic conductivity rates and water characteristic curves were measured in the laboratory. Soil strength was measured in the field with a tractor mounted soil cone penetrometer and in the laboratory using a modulus-of rupture technique. Differences in infiltration rates at the soil surface among the sites ranged from over 7 cm/hr for the native prairie to less than a 0.25 cm/hr for the long-term corn-soybean rotation. For the claypan horizon, saturated hydraulic conductivities for the 50-year EG site were higher than those for the native prairie site because of a higher percentage of large pore space, an unexpected finding. Growing EG on claypan soils is one biological means to improve soil quality. EG roots have aerenchyma tissue which helps the roots grow through the often poorly aerated claypan. Corn, soybean, and other crop roots can then grow through the old EG root channels. Improving claypan soil quality will have a number of benefits including decreased surface runoff and improved surface water quality, more soil water available for crop production, and decreased drought stress through increased crop rooting.