Impacts of 2008 flooding on agricultural lands in Illinois, Missouri, and Indiana

Excerpt

The 2008 spring rains in Illinois, Missouri, and Indiana delayed planting, drowned corn and soybean plants, and resulted in significant replanting. From May 30, 2008, to June 12, 2008, the previously saturated soils could not retain any more rainfall, and the wetlands, potholes, and depressions in the upland landscape filled with water (figure 1) and then began to runoff through waterways and into small streams (figure 2). As much as 30% of the upland soils in south central Illinois, northern Missouri, and southern Indiana were affected by ponding. Approximately one-third of that ponded acreage was not replanted in 2008. As overland flow started to occur, so did sheet, rill, and gully erosion. Where significant topsoil loss occurs, it can eventually result in the erosion phase change of the soil. Any soil erosion phase change from slightly to moderately or severely eroded can reduce the crop yield potential from 0.3 to 1 Mg ha⁻¹ (5 to 15 bu ac⁻¹), depending on whether the soils have favorable or unfavorable sub-soils for rooting. One year's erosion events do not change the erosion phase of the soil unless gullying occurs. However, the 2008 soil loss, when added to the soil loss from erosion in…