Color/Texture for Normandy Soil?

Am finishing up a Tamiya Cromwell for the Finescalle D-Day build. I'm going to be concentrating on netting and foliage - both new techniques for me - but certainly common in June 1944 on both sides of the line.

I just spent more money on dried arctic sage than a set of metal tracks.(Of course you can only use the tracks once.)So I would like to get the pigments and mud right. Normandy is fertile and gets a lot of water. I try to think of areas in Minnesota that fit that description and the soil is moist and usually very dark - a dark brown to almost black. All tanks in the field more than a few days are going to pick up dust in good quantity and at least some dense soil (a kind of moist mud maybe). Any advice on what colors or texture of soils one might find in Normandy?
Eric