Genotype and Planting Date Influence on Establishment and Growth of Bassia prostrata (L) A.J. Scott in a Semiarid Subtropical Dry Winter Region

Alfalfa (Medicago sativa L.) growers in semiarid subtropical regions seek forage crops having a lower irrigation requirement. Perennial forage kochia (Bassia prostrata (L) A.J. Scott (syn. Kochia prostrata)) can potentially fill this need. The New Mexico State University’s Agricultural Science Center at Tucumcari evaluated four genotypes of B. prostrata (subspecies virescens ”Immigrant” and “Pustinny-select” and subsp. grisea “Snowstorm” and “KZ-6X”) that were direct-seeded in March and May of 2014 under irrigation in semiarid continental precipitation conditions, in three randomized complete blocks. Canopy cover was rated in 2016 and 2018 and biomass production was measured in 2018. Snowstorm did not establish on either date. Canopy cover remained unchanged across years. Immigrant established the greatest canopy cover for the March seeding and Pustinny-select had greater canopy cover for the May seeding. The May seeding tended (p < 0.10) to have greater biomass production than the March seeding (12,357 and 8909 kg ha−1, respectively, SEM = 2454). Irrigation or adequate precipitation to maintain soil moisture and weed control are critical to B. prostrata establishment by direct seeding, especially in dry winter regions. Further research is necessary to determine the potential of this species as an alternative to alfalfa in semiarid, subtropical, and continental precipitation regions.

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

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 tectorumL.) and one to study the effect of forage kochia on growth of native perennial grasses. In the first experiment, a single seedling ofB. tectorumwas grown with increasing neighbor densities (0 to 5 seedlings pot−1) of either forage kochia, crested wheatgrass [Agropyron cristatum(L.) Gaertner ×A. desertorum(Fisch. ex Link) Schultes; nonnative perennial grass], or thickspike wheatgrass [Elymus lanceolatus(Scribn. & J. G. Sm.) Gould; native perennial grass].Bromus tectorumgrowth was reduced moderately by all three perennial neighbors, butA. cristatumandE. lanceolatushad more effect onB. tectorumwhen 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.) Á. Löve], bluebunch wheatgrass [Pseudoroegneria spicata(Pursh) Á. Löve],E. lanceolatus, and western wheatgrass [Pascopyrum smithii(Rydb.) Á. Löve]. 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 ofL. cinereusandP. spicata. However, all native grasses significantly reduced change in height, branching, and aboveground biomass of forage kochia. These results suggest that forage kochia interfered withB. tectorumseedling growth, but it showed little competitive effect on native grass seedlings.