the ability to view soil microbes in situ is important since it allows students to view the interrelationships between soil microbes and their interactions with soil particles. However, it is difficult to observe colloidal size microbes that exit within soil. A technique developed back in the 1930s is still a valuable learning tool today. This is the contact slide or buride-slide technique of Rossi et al. (1936), which is a simple technique for qualitatively assessing the spatial relationships between soil microorganisms. Although it is not reliable enough to quanfity soil microorganisms as the original auothors had intended, it is useful to illustrate the orientation of soil organisms to one another and to soil particles.It also allows students to see bacteria, actinomycetes and fungi, perhaps. For the first time, through the use of microscope (Mairer et al., 2000). The technique involves burying a glass slide in soil for a defined period of time (figure 3-1). Nutrient amendments, such as the carbon source glucose and the nitrogen source ammonium nitrate, encourage the rapid proliferation of heterotrophic microorganisms.