Soil is a complex of living and non-living components which are present in different combinations. The attached sites and publications might be helpful to you.

1. http://rd.springer.com/referenceworkentry/10.1007%2F978-1-4020-6359-6_4266

2. Soil mite densities from central Ivory Coast (http://www.academia.edu/6856520/Soil_mite_densities_from_central_Ivory_Coast)

3. The Soil Mites of the World. Volume 1: Primitive Oribatids of the Palaearctic Region

by J. Balogh Author · S. Mahunka Author

4. Effects of soil amendments on assemblages of soil mites (Acari: Oribatida, Mesostigmata) in short-rotation willow plantings in central New York