In general, the acreage of cropland is decreasing, and that of improved pasture and urban development is increasing. Sloping to rolling sandstone-capped hills and ridges rise prominently above the surrounding uplands. Stream valleys are narrow and have steep gradients. Local relief is mostly from 1 to 10 or 15 m. Average annual precipitation - 875 to 1,000 mm.
Maximum precipitation is in spring and in fall.
Average precipitation during the frost-free period is about 600 to 650 mm. The summer moisture deficit ranges from about 125 to 200 mm. The moderate and somewhat erratic rainfall is the major source of water for pasture and crops. Large reservoirs provide water for cities and towns and for recreation. Farm ponds are a major source of water for livestock.