About a third of the farmland is in woodlots. The Claypan Area is a nearly level to sloping plain. Dissected sites are steeper along entrenched river and creek valleys. Valleys of large streams are shallow, and the wide flood plains are bordered by nearly level terraces. Average annual precipitation -750 to 1,075 mm.
Maximum precipitation is in winter and in spring, and the minimum is in summer and in autumn.
The moderate precipitation is the major source of water for crops and pasture. Rainfall in summer is erratic, and in most years crop yields are reduced by a lack of moisture. A few large reservoirs on major streams provide municipal water and also serve as recreation facilities. Water for farm use comes from ponds and wells. They are deep, medium textured and moderately coarse textured soils that have a slowly or very slowly permeable clayey subsoil.