부산대학교 도서관

An extensive bibliographical study documenting rooting patterns of native and introduced plants of the Western United States resulted in a computerized data base of over 1000 different rooting depth citations. From that data base, average rooting depths and frequencies were determined as related to species, habit, soil type, geographic region, root type, family, root depth to shoot height ratios, and root depth to root lateral ratios. Annual grasses were found to root within 1 m of the soil surface. Median rooting depth of other life forms was 2.0 m with a maximum rooting depth of 61 m. The various life forms had the following median and maximum rooting depths: annual forbs (median of 0.6 m, maximum of 3.0 m), biennial forms (0.8 m, 1.5 m), perennial grasses (1.1 m, 8.2 m), perennial forbs (1.1 m, 39.0 m), subshrubs and vines (1.2 m, 6.4 m), shrubs (2 m, 17.0 m), and trees (1.6 m, 61 m). In addition to the bibliographic study, 21 species common to the pinyon-juniper woodland were excavated from soils derived from volcanic tuff in Northern New Mexico. Rooting patterns and gross morphology were examined. Perennial forbs and grasses occurred within the first 30 cm of the soil surface. Roots of the overstory trees were traced to depths of 6 m and roots of shrubs to depths of 1.8 to 2.6 m. 29 refs., 2 figs., 6 tabs.