Teaching soil ecology in one lab session Becky Ball Arizona State University West Campus

Pre-lab lecture: Review basics of soil formation, profile, and components. Talk about variation among ecosystems, as well as within ecosystems. Have students generate hypotheses about how soils might differ within their campus ecosystem (based on plant cover, management, etc.)

Using a soil test kit. Methods from the accompanying instructions are posted on the board. Before measuring pH: Discuss role of base cations and cation exchange Before measuring texture: Discuss how soil water holding capacity and aeration influence biology. Using the tactile method of making a ribbon from a wet ball of soil

Use a soil test kit. Methods from the accompanying instructions are posted on the board. Before measuring N: Review the importance of nutrients in productivity. Discuss why N is frequently limiting in ecosystems.

Using pre-extracted microarthropod samples that I collect before the lab. Method is discussed in lab. Before counting microarthropods: Review the soil food web Introduce the various taxa they are likely to encounter Emphasize that these biota are responsible for key processes (and that, essentially, they run the world). Emphasize the vast amount of biodiversity in the soil.