Rate of Weed Root Elongation

Abstract

Considerable differences in rate of root elongation were observed. Species studied in order of decreasing rate root elongation were cocklebur (Xanthium pensylvanicum Wallr.), palmer amaranth (Amaranthus palmeri S. Wats.), barnyardgrass (Echinochloa crusgalli (L.) Beauv.), buffalobur (Solanum rostratum Dunal), kochia (Kochia scoparia (L.) Schrad.), crabgrass (Digitaria sanguinalis (L.) Scop.), sorghum (Sorghum vulgare L., var. RS 610), Russian thistle (Salsola kali L., var. tenuifolia Tausch), and tumblegrass (Schedonnardus paniculatus (Nutt.) Trel.). In 15 days, cocklebur and tumblegrass roots grew 33 and 11 in, respectively. With all species, the rate of root elongation always exceeded the rate of height increase. There was poor correlation between rate of root elongation and weed height, top weight, and root weight.