Prebiotic biostimulation for enhanced soil microbial activity and growth of diverse native grasses

Given the urgency of addressing grassy ecosystem loss, there is a growing demand for cost-effective, evidence-based restoration and revegetation strategies for Poacaeae. Prebiotics applied to soils to promote microbial activity and diversity are widely used for grass crops in agriculture, but their efficacy in improving native grass establishment remains largely untested. Here, we investigate the efficacy of a commercial prebiotic soil biostimulant in improving the performance of 13 diverse native grasses. Glasshouse plant growth trials were conducted to assess the impact of the carbon-rich prebiotic on soil microbial and physicochemical characteristics and the biomass and health of grass species compared to untreated controls. Rhizosphere bacterial diversity and composition were also quantified and analyzed for each grass species examined. Prebiotic biostimulant application resulted in enhanced soil microbial activity and significantly increased grass growth relative to untreated controls. Although the overall composition of rhizosphere bacterial communities was similar between treated and control samples, specific taxonomically and physiologically diverse bacterial taxa associated with various plant growth-promoting traits showed significant positive responses to the prebiotic treatment. We show that prebiotic biostimulation can promote the growth of diverse native grass species, likely influencing soil–microbe–plant interactions, highlighting potential for future testing of prebiotic biostimulants in field trials of restoration in grassy ecosystems.