Agriculture, Ecosystems and Environment, 34 ( 1991 ) 235-249 235 Elsevier Science Publishers B.V., Amsterdam Methods used in rhizosphere ecology A new dawn for soil biology: video analysis of root-soil-microbial-faunal interactions John Lussenhop 1, Robert Fogel2 and Kurt Pregitzer 3 J Biological Sciences Department, University of Illinois at Chicago, Box 4348, Chicago, IL 60680 (U.S.A.) 2University of Michigan Herbarium, Ann Arbor, M148109 (U.S.A.) 3Department of Forestry, Michigan State University, East Lansing, M144824-1222 (U.S.A.) (Accepted for publication 5 July 1990) ABSTRACT Lussenhop, J., Fogel, R. and Pregitzer, K., 1991. A new dawn for soil biology: video analysis of root- soil-microbial-faunal interactions. Agric. Ecosystems Environ., 34: 235-249. Roots and their biota interact from the smallest spatiotemporal scale at the level of bacteria, to intermediate fungal-invertebrate spatiotemporal scales, and ultimately to the large, scale of structural roots. The micron-second bacterial scale is best known because it is amenable to standard microbial techniques. Intermediate and large spatiotemporal scales of interaction need comparable study be- cause events at each scale affect the others. Borescopes, minirhizotrons and soil biotrons are well- suited to studying events at the intermediate, millimeter-minute spatiotemporal scale of fine roots, fungi and invertebrates. Soil biotrons are particularly well-suited for study of the intermediate spatio- temporal scale because microscopes, cameras and video can be used within them, and in situ experi- mental manipulations can be performed. The large amounts of observational data that can be col- lected with video recording can be analyzed using computer image analysis. Image analysis is especially valuable in visualizing the spatial relationships of roots and their biota, and in quantifying growth, feeding and turnover rates. INTRODUCTION Most students of rhizosphere processes must study organisms or processes by isolating them from the complex web of interactions in which they occur. Roots are sieved from soil or grown in plastic pouches, bacteria and fungi are cultured, and invertebrates extracted from soil - all without ever actually ob- serving them in place. Thus the whole spatiotemporal aspect of rhizosphere interactions is poorly known because each group of organisms is removed from its setting for study. It is our purpose to review rhizosphere processes emphasizing the spatio- 0167-8809/9 !/$03.50 © 1991 -- Elsevier Science Publishers B.V.