Comparisons of cultivation methods for Lupinus sericeus, L. argenteus, L. prunophilus, and L. arbustus

Abstract

Fire and invasive weeds have increased the demand for native seed for restoration across the Great Basin region of the US. Cultivation of native forbs could provide lessexpensive seed in necessary quantities to meet restoration needs that cannot be harvested from wildland populations alone. We evaluated 2 cultivation methods of 4 lupine species (Lupinus (Tournefort) [Fabaceae])—hairy bigleaf lupine (L. prunophilus M.E. Jones), silky lupine (L. sericeus Pursh), silvery lupine (L. argenteus Pursh), and longspur lupine (L. arbustus Douglas ex Lindl.)—to evaluate emergence, establishment, and seed production. We compared the conventional cultivation method of row crop production (control) using direct drilling to an experimental cultivation method of broadcast seeding with a mulch covering of sawdust and N-Sulate fabric (covered treatment). Under covered treatment conditions, emergence was significantly improved compared to conventional cultivation for all 4 lupine species, with P values of < 0.0001 for all 4 species. Similar results were found in 2nd-year establishment rates for silvery lupine, hairy bigleaf lupine, and silky lupine with all P values < 0.0001. Longspur lupine showed symptoms of iron deficiency chlorosis during the 1st growing season and consequently no plants established in subsequent years. Silvery lupine and silky lupine produced significantly more seed in the covered treatment than in the control with P values of < 0.0001 for both species. Our mulch treatment effectively increased emergence, establishment, and seed production in all surviving cultivars compared to the control method.