Figure 1

BR (a) and SIR (b) in the rhizosphere and bulk soil in the treatments. Different lowercase letters indicate significant differences between treatments in the rhizosphere. AN0, ambient CO₂ and no N added; AN1 ambient CO₂ and N supply at a rate of 2.5 g N m⁻² y⁻¹; AN2, ambient CO₂ and N supply at a rate of 5 g N m⁻² y⁻¹; EN0, elevated CO₂ and no N added; EN1, elevated CO₂ and N supply at a rate of 2.5 g N m⁻² y⁻¹; EN2, elevated CO₂ and N supply at a rate of 5 g N m⁻² y⁻¹.