The role of seed mix characteristics and soil amendments during post‐agricultural prairie restoration

Introduction Prairie restoration on degraded lands may be influenced by seed mix characteristics, including species richness and legume establishment. Soil amendments may facilitate restoration; however, the practical usefulness of techniques such as applications of whole soil and leaf mulch remains relatively unclear. Objectives We assessed whether increasing species richness and legume content in seed mixes enhances prairie restoration success and examined how soil amendments interact with seed mix composition to influence cover, species richness, diversity, and legume establishment. Methods We conducted a field experiment on a 12‐ha post‐agricultural site in Ohio, U.S.A. Twenty 50 × 50 m plots received one of four prairie seed mixes varying in species richness (39 vs. 25 species) and legume content (20% vs. 5% by seed weight). Each plot was subdivided into four subplots receiving leaf mulch, whole‐soil inoculation, mulch plus soil, or no amendment. Vegetation surveys quantified cover, species richness, diversity, and legume cover. Results After 3 years, we found that higher richness seed mixes increased species richness but did not enhance diversity. Increasing legume content in seed mixes did not result in greater legume cover. Non‐seeded legumes established widely, and dominance by the non‐seeded native species Symphyotrichum pilosum suppressed species diversity without reducing species richness. Conclusions Seed mix composition and soil amendments interact in complex ways that can influence restoration outcomes. Prairie establishment depends on site‐specific factors and stochastic recruitment dynamics.