Northwest Iowa Crops Page
by Todd Vagts
ISU Extension Crops Specialist
Counties Served:  Carroll, Calhoun, Crawford, Ida, Monona, Pocahontas and Sac.

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Fall 2003 Subsoil Moisture Survey Results

• Counties:  Carroll, Calhoun, Sac, Crawford, Monona and Ida
• Date Sampled:  October 23 (Sac County), October 27 (Carroll, Calhoun Ida, Monona and Pocahontas Counties).

Graphs (pdf)
Detailed Excel worksheet

State-wide map and Commentary by Elwynn Taylor

Results from this fall’s sampling indicate that west-central and north-west IA (as may have been expected) is going into the winter season with a very dry soil profile.  The average plant available water in the 7-county area is 2.6 of a potential 11 inches, or 24% of the soils capacity.  The region’s soil moisture level is 56% of the 5-year fall average compared to last fall’s 180% of the 5-year fall average.  The soil moisture sampling occurred the last week of October, so the rainfall the area received in early November is not represented in these data.

Last spring’s sampling indicated very good soil moisture profiles across the region representing the plentiful rainfall the area received in the fall of 2002.  When compared to the average spring moisture levels (1999 – 2003), the spring 2003 sub-soil moisture condition is about 115% of the 5-year average.   The stored moisture greatly benefited the 2003 crop through many dry periods. 

Southern Sac and Carroll counties were the only areas showing decent fall soil moisture levels with moistures ranging from 3.9 to 6.4 inches plant available water.  All other areas had plant available water at levels less than 3.2 inches (29% of capacity) with a low of 0.5 inches near Castana in Monona County.  Much above normal precipitation during the fall and spring period will be required to bring soil moisture levels up to levels we would like to see in the spring.  Figuring about 70% efficiency in capturing precipitation in the soil, the area will need about 10.7 inches of rain before planting to bring the soil to capacity.