Ecosystem degradation often depletes or disturbs soil microbial communities1,2 which can be deleterious for soil health and can disrupt plant–microbe symbioses3. Revegetation of native plants is an important activity for ecosystem restoration but is often hindered due to low germination rates and poor seedling establishment4. Soil prebiotics are products that increase the activity of indigenous microbes in the soil by supplying compounds that may be limiting in the environment5. They are often used in agriculture as a sustainable alternative to inorganic fertilisers to improve soil fertility, functionality and crop yields, however, their efficacy for native species is largely unknown.
This study investigates the efficacy of a commercial prebiotic soil prebiotic in stimulating soil and plant-associated microbes to improve the germination and growth of diverse, restoration-important native grasses. Greenhouse plant-growth trials were conducted to assess the impact of the carbon-rich product on soil microbial activity, physicochemical characteristics, and the biomass and health of 13 grass species compared to untreated controls. Rhizosphere bacterial diversity and composition were also analysed for each of these grasses. Prebiotic application resulted in enhanced soil microbial activity, organic matter, and nutrient availability, and increased plant growth relative to untreated controls. While the overall composition of rhizosphere bacterial communities was similar between treated and control samples, specific microbial taxa responded positively to the prebiotic.
This study provides evidence that use of soil biostimulants has potential to affect natural soil-plant-microbe interactions and promote the growth and persistence of native plants, with potential to contribute to more sustainable and resilient grassland restoration. Ongoing field trials aim to validate these greenhouse findings under natural conditions, while also evaluating potential off-target effects and weed competition.