Distribution of Roots in Soil, and Root Foraging Activity

Abstract

A knowledge of the pattern of root distribution in soil is critical to a number of areas of ecology. For example, our ability to model the interactions between climate and vegetation depends in part on our knowledge of the global pattern of distribution of belowground biomass at various soil depths, and how it will change as one vegetation type replaces another (Jackson et al. 1996). Similarly, our understanding of ecosystem processes is currently limited by poor understanding of the distribution, quantity and productivity of fine roots within a variety of ecosystems, even though, for example, the annual production of fine roots may be twice that of leaves in Northern American hardwood forests (Fahey and Hughes 1994), and up to 80 % of the biomass of some ecosystems is underground (Jackson et al. 1996). At a more local scale, we are limited in our ability to accurately model the processes involved in plant competition by our inadequate knowledge of the fine-scale distributions of roots of individual plants and of the distribution of their associated symbionts (Mou et al. 1995; Casper and Jackson 1997; Casper et al. 2000).