Figure 3.

Plant–soil feedbacks for S. pulchra (A) and A. fatua (B) grown alone or with a competitor, across soils cultured by conspecifics or heterospecifics under varying resources. Stipa experienced positive feedbacks (i.e. grew better with its home soil communities) when grown alone in low N and ambient N soil communities, but these feedbacks became negative when grown in high N soil communities. Avena grew worse in its conspecific soil compared with heterospecific low N soil communities, resulting in a negative feedback. Means ± 1 SE. Significantly different from zero: *P < 0.05, **P < 0.01.