Soils4Kids has a site with some cool experiments that can be done with or to learn more about soils
Want learn science for kids, edited by kids? Check out Frontiers for Young Minds, this site has articles that are written by scientific experts, but they are always reviewed by young people to make sure that they are clear and easy to understand.
Soil-net.com has resources for kids of all ages. These fun activities are broken down by grade level. There are also case studies and ideas for teachers and parents.
The layers of soil are full of different properties, find out about the O horizon, A Horizon(top soil), B Horizon (subsoil), C Horizon (weathered parent material) and Bedrock basic properties in this video.
Why is Biodiversity in our soils so important, Check out this video to find out!