Two Methods for Characterizing Rooting Depth of Forage‐Legume Seedlings in the Field

Abstract

Because rooting characteristics are difficult to investigate, little research has been done on the root development of legume seedlings. Both the growth pouch and slant tube methods may provide rapid and relatively inexpensive methods for investigating seedling root development. Our objective was to determine the relationship between rooting depths of forage legumes grown in growth pouches and slant tubes with rooting depths in the field. Forage legumes were grown in slant tubes in the greenhouse and in growth pouches held in the dark at constant temperatures ranging from 10 to 30 °C and compared with rooting depths of the same legumes grown in the field. At 10 d after planting (DAP), root length in pouches for 20 and 25 °C were correlated (P < 0.01) with rooting depth (r2 = 8.87) in the field at 32 DAP. Root lengths in slant tubes at 14, 18, and 25 DAP were correlated (P < 0.01) with field rooting depth at 32 DAP and r2s were 0.69, 0.71, and 0.62, respectively. Thus, both growth pouches and slant tubes appear useful for screening rooting characteristics of forage legume seedlings.