Effect of Forage Kochia on Seedling Growth of Cheatgrass (Bromus tectorum) and Perennial Grasses

摘要

Forage kochia [Bassia prostrata (L.) A. J. Scott] is competitive with annual weeds and has potential for use in reclamation of disturbed land. However, land managers are reluctant to use forage kochia in revegetation programs due to lack of understanding of its compatibility with or invasiveness in the native plant community. We conducted two greenhouse experiments, one to compare the competitive effect of forage kochia versus perennial grasses on growth of cheatgrass (Bromus tectorum L.) and one to study the effect of forage kochia on growth of native perennial grasses. In the first experiment, a single seedling of B. tectorum was grown with increasing neighbor densities (0 to 5 seedlings pot(-1)) of either forage kochia, crested wheatgrass [Agropyron cristatum (L.) Gaertner x A. desertorum (Fisch. ex Link) Schultes; nonnative perennial grass], or thickspike wheatgrass [Elymus lanceolatus (Scribn. & J. G. Sm.) Gould; native perennial grass]. Bromus tectorum growth was reduced moderately by all three perennial neighbors, but A. cristatum and E. lanceolatus had more effect on B. tectorum when compared with forage kochia. This experiment was repeated and similar results were observed. In the second experiment, forage kochia was grown with each of four native cool-season grass species: basin wildrye [Leymus cinereus (Scribn. & Merr.) a. Love], bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) a. Love], E. lanceolatus, and western wheatgrass [Pascopyrum smithii (Rydb.) a. Love]. Forage kochia had no effect on height, tiller number, and aboveground biomass of native grasses. Similarly, native grasses did not show a significant effect on forage kochia seedlings. This experiment was also repeated, and forage kochia somewhat reduced the aboveground biomass of L. cinereus and P. spicata. However, all native grasses significantly reduced change in height, branching, and aboveground biomass of forage kochia. These results suggest that forage kochia interfered with B. tectorum seedling growth, but it showed little competitive effect on native grass seedlings.