Biochar Concentration Is More Important than Nitrogen Form in the Nursery Production of Desert Globemallow (Sphaeralcea ambigua A. Gray) Seedlings for Restoration

Desert globemallow (Sphaeralcea ambigua A. Gray) is a native perennial forb that plays a critical role in the southern Great Basin and Mojave Desert ecosystems of North America, but research on its development and propagation is scarce. Because nursery-produced seedlings may be useful in restoration, we explored displacing sphagnum peat moss in a conventional substrate with biochar (0%, 15%, and 30% v:v) in combination with commonly used nitrogen (N) forms (ammonium, nitrate, and ammonium nitrate). Our objective was to determine which combination yielded desert globemallow seedlings with the highest quality. At the end of a 4-month trial, increasing concentrations of biochar were associated with increases in shoot height, biomass, and leaf area; leaves produced with biochar were thicker. These increases were concurrent with increases in primary root mass, area, length, and diameter. Although N interacted with biochar concentration, it was rarely significant as a main effect. This research offers valuable insights into the nursery cultivation of desert globemallow, highlighting the complex interactions between media amendments, plant physiology, and growth strategies in arid and semi-arid ecosystems. It underscores the importance of biochar and N applications in propagating seedlings for enhancing sustainable ecosystem management, restoration efforts, and agricultural practices in arid regions.