Iowa State University Extension and Outreach has completed its annual fall survey to determine the amount of moisture in the subsoil levels of northwest Iowa.  Soil moisture samples are measured at five feet at each one-foot increments at pre-determined locations both in the spring and in the fall.  As you might expect, soil moisture levels are well below average.  Leah Ten Napel serves as the ISU Extension agronomist for northwest Iowa.  There are 16 total testing locations within northwest Iowa.  Eleven are located within the nine-county region that Ten Napel serves.  She says in some areas of her region soil moisture levels are at least six inches short of average.  The ISU extension agronomist says corn and soybean crops require about 20 inches of moisture from rainfall and subsoil moisture to produce a crop.  That number may increase to 25 inches of moisture if we have high temperatures and windy conditions.