Interactions between soil properties, soil microbes and plants in remnant-grassland and old-field areas: a reciprocal transplant approach

Background and aims: The importance of plant-soil feedback is becoming widely acknowledged; however, how different soil conditions influence these interactions is still relatively unknown. Using soil from a degraded old-field and a remnant grassland, we aimed to explore home-field advantages in plant-soil feedbacks and plant responses to the abiotic and biotic soil conditions. We quantified the soil bacterial and fungal community from these sites and their responses to soil conditions and plant species. Methods: Sterilized old-field and remnant-grassland soil was inoculated with home or away soil in a reciprocal transplant experiment using a native grass, Rytidosperma auriculatum, and an invasive grass, Avena barbata, as test species. The soil fungal and bacterial communities were characterised using high throughput sequencing. Results: Plants had a greater growth response to microbes when an inoculant was added to its home soil. However, this relationship is complex, with microbial communities changing in response to the plant species and soil type. Conclusion: The apparent home-field advantage of the soil microbes shown in this study may restrict the utility of inoculants as a management tool. However, since we inoculated sterile soil, future work should focus on understanding how the inoculated microbial community interacts and competes with resident communities.