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Monday, February 9, 2015

Most Interesting Area I Soil Mapped

I worked on soil surveys in Madison, Lee, Bureau, and Putnam Counties in Illinois early in my career.  In my  7 1/2 years as an NRCS soil scientist I covered about 150,000 acres on foot looking at soils and attempting to map out the soils I was seeing according to the five factors of soil formation.  The area is part of Franklin Creek State Park near Franklin Grove Illinois.  Lots of geological formations converge near the center of the map.  The state park link above explains that there are three bedrock formations in the area.  The bedrock includes both sandstone 397F (Boone) and limestone 403F (Elizabeth).  Some soils have glacial till and bedrock influences 509D (Whalan) and 761F (Eleva).  361D (Kidder) is a soil formed from sandy loam Illinoisan age glacial till. 243A and 243B (St. Charles) are soils formed in loess underlain by old alluvium on a stream terrace the 570B is also a stream terrace soil, but contains more sand.  The area of 1776 (Comfrey) is a very poorly drained bottomland soil that is extremely wet because of a beaver dam in the creek. the 3451A (Lawson) and 8776 (Comfrey) areas are also bottomland soils, but they are not so wet that they could not be farmed.   To add to the extreme soil diversity of the area, The upper right hand of the map is 280B (Fayette), a well drained soil formed entirely in loess.  I spent a whole day near the center of the map looking at 160 acres of landscape that was very confusing at the time.  160 acres is normally 2 or 3 hours of work.

I don't remember every acre I ever mapped, but t his is one area I will never forget.  Some 25 years after the field experience I was sitting at a table having supper with NRCS State Soil Scientist Bob McLeese and Northern Illinois soils professor Mike Konen. Konen was tell McLeese about an interesting area he had been taking is students to because of the diversity of the soils.  As I listened to him describe the area, I realized that he was describing the area I had mapped many years before.  I told them about mapping it and how difficult it was to define the boundaries. 

It is also interesting that this ecological wonder is located less than a mile away from the Nachusa Grasslands, another ecological wonder.Click on the map below to enlarge.