Many methods are used to study plant root system development and function. Most methods are tedious and time‐consuming. Some require expensive, sophisticated equipment and frequently require highly trained operators. Few studies are published where several methods are compared for their time requirements, equipment needs, soil applicability, and validity of the results. This study determined usefulness of five methods for characterizing soybean (Glycine max (L.) Merr.) rooting depth and density in a loess [fine, silty, mixed (calcareous) mesic family of Typic Udorthents] soil. The methods were: (a) soil water‐depletion, (b) framed‐monolith and pinboard, (c) core‐sampling, (d) mini‐rhizotron, and (e) trench‐profile. Each method was used or attempted on several dates during the 1975 growing season. The soil water‐depletion method was fast, required only simple equipment, and provided satisfactory estimates of rooting depth but did not provide reliable estimates of rooting density. The framed‐monolith method was very time‐consuming, but provided quantitative estimates of rooting density with depth and could have provided rooting density estimates with distance from the row. The core‐sampling method was faster than the framed‐monolith method. Cores could be obtained either with a hand‐turned bucket auger or with a coring machine, but several profiles were required to obtain rooting density distributions with depth and distance from the row. The mini‐rhizotron method was fast, but did not provide accurate results, presumably because the mini‐rhizotrons were installed too late. The trench‐profile method provided semiquantitative estimates of rooting density with depth and distance from the row. The trench‐profile method was rapid and required no time‐consuming separation of live roots from debris of previous years. The hand‐augered core, soil water‐depletion, and the trench‐profile methods could be used through the entire growing season, but the framed‐monolith and the mechanized‐core methods were not satisfactory during a drought period because the soil column collapsed during sampling.

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