Root Elongation along a Soil‐Plastic Container Interface1

Root growth is often studied in glass‐fronted containers which allow continuous observation of several growth parameters. These observations are generally assumed to extrapolate to root growth under field conditions. However, laboratory studies reported here show that root elongation rates along a soil‐container interface in soil cores are significantly lower than those measured within the bulk soil mass. These differences are probably due either to higher soil strength at the interface or to an attracting electrical charge on the container surface, or both.