Studying plant-soil feedback (PSF) is a promising approach to study the net effect of positive and negative effects of plant-soil interactions to explain plant community development. While promising PSF research remains notably limited to measuring plant monocultures in greenhouse experiments. To address the importance of PSF in structuring plant community we used a field-based, common garden experiment to assess how plant communities respond to differently-cultivated soils. A three-species native plant mix and a three-species non-native mix was grown on soils cultivated by two native plants, three non-native plants or a mixed plant community.
Native plant growth was similar among soil types, except lower on soil cultivated by Centaurea diffusa – the dominant non-native plant in the study area. Non-native growth differed among sites but was notably smaller on soil cultivated by Pseudoroegneria spicata – the dominant native plant in the study area. Results suggest that the dominant native plant creates soils that suppress growth of the dominant non-native plants and the dominant non-native plant creates soils that suppress growth of the dominant native plants. When used in a new spatially-explicit PSF model, the data suggest that PSF explains the distribution of native and non-native plants observed on the landscape. While the mechanisms remain unclear, analyses revealed clear differences in the bacterial and fungal community composition between C. diffusa and P. spicata soils. Results from this relatively long-term, field-based experiment provided clear support for the role of PSF in determining native and non-native plant growth on the landscape.