FIGURE 4 . Response of relative shoot biomass of plant species (Stipa breviflora , Agropyron mongolicum ,Cleistogenes squarrosa , Chenopodium aristatum and other species) to nitrogen addition (N) and phosphorus addition (P) in mycorrhizal (black bars; non-benomyl addition) and mycorrhizal-suppressed (white bars; benomyl addition) plots in 2019 (a, b) and 2020 (c, d).