ABSTRACT

The soils of central and western South Dakota have a clay or clay loam texture since they were formed from marine shale. The landscape is gently to moderately rolling and has a well-defined drainage system. Growing season precipitation is about 350400 mm and frequently occurs as 30-60 mm shower events in the summer. Rill erosion is commonplace as runoff often exceeds infiltration. The region has a continental type climate and mean monthly temperature ranges from -7°C in January to 26°C in July. Summertime temperatures often exceed 35°C in the daytime and winter temperatures can be sustained at -20°C for many days. The region has an average of 1700 growing degree (°С) days.