Armstrong Research and Demonstration Farm
Each spring and fall a soil moisture survey is conducted to determine the amount of plant available moisture in the top five feet of many of the major soil types in Iowa. Several of the sites, which are the same each year, are located in the area served by the Wallace Foundation for Rural Research and Development (WFRRD). Many producers make or alter their crop management plans according to expected soil moisture levels.
Iowa State University
McGrath, Clarke, "Soil Moisture Survey" (2004). Iowa State Research Farm Progress Reports. 1309.