Abstract

Revegetation of reclaimed lands is often limited by poor seed placement, unfavorable surface conditions, and reduced biological activity, particularly on steep or physically degraded substrates where broadcast seeding is commonly used. Improving early seeding establishment under these conditions requires approaches that address both physical and biological barriers to seedling development. We evaluated the effectiveness of surface preparation, seed technologies, and microbial inoculants for improving plant establishment in field and greenhouse settings relevant to mineland reclamation. At the field scale (Chapter 1), we investigated the effects of chain harrowing and seed enhancement treatments on the establishment of grasses, forbs, and shrubs in two experiments conducted on reclaimed waste rock dumps. Chain harrowing consistently increased seedling establishment, particularly for large-seeded forbs and shrubs, by improving seed-soil contact and microsite conditions. A gibberellic acid (GA₃) plus fungicide seed coating produced establishment gains comparable to harrowing for large-seeded species, indicating that seed-applied technologies can partially offset poor seed placement where mechanical disturbance is not feasible. Soil application of Trichoderma spp. enhanced establishment primarily when combined with harrowing, suggesting interactions between seedbed conditions and biological amendments. To further resolve biological responses under inoculant performances, we evaluated locally sourced Bacillus, Trichoderma, and Kushneria inoculants on alfalfa (Medicago sativa) establishment in disturbed substrate under controlled greenhouse conditions (Chapter 2). Plant responses were strain- and trait-specific, with certain inoculants like Bacillus 2 and Kushneria isolates substantially increasing aboveground biomass or root development, while others showed limited effects compared to non-inoculated alfalfa. Together, these results indicate that reclamation seeding success is governed by interacting physical, physiological, and biological limitations. Mechanical surface modification remains the most reliable means of improving establishment under broadcast seeding, but seed enhancement technologies, particularly gibberellic acid (GA₃) plus fungicide seed coatings, and targeted microbial inoculants offer tools that can improve outcomes when aligned with species traits, site conditions, and management constraints.

Degree

MS

College and Department

Life Sciences; Plant and Wildlife Sciences

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2026-04-21

Document Type

Thesis

Keywords

microbial inoculants, harrowing, seed coating, gibberellic acid, Trichoderma, alfalfa, Kushneria, Bacillus

Language

english

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