As we write this article spring rains are coming hard and fast causing substantial soil erosion when soils are most vulnerable because of degraded crop residue cover, soil preparation by tillage and no crop canopy. The soil profiles in most of Iowa are now filled to capacity with water. The profiles are at or near saturation. Therefore, the intensity and amount of rain we received have exceeded the soil capacity to filter water and minimize surface runoff even in fields with the most adequate conservation practices.
Iowa State University
Al-Kaisi, Mahdi and Helmers, Matthew J., "Heavy Rain, Soil Erosion and Nutrient Losses" (2008). Integrated Crop Management News. 891.