The means (±SE) for each variable followed by different uppercase letters indicate significant differences between grazing and exclusion sites (P < 0.05). The lowercase letters indicate significant differences among different grassland types (P< 0.05). Based on two-way variance comparisons. SWC, soil water content; BD, bulk density; SOC, soil organic carbon; KN, Kjeldahl nitrogen; TP, total phosphorus; C:N, carbon:nitrogen; C:P, carbon:phosphorus; N:P, nitrogen:phosphorus.
3.2. Soil fungal community OTU numbers as affected by grazing exclusion and grassland type
Wayne analysis (Fig. 2) showed that in the 0-5 cm soil layer (Fig. 2A), the number of fungal operational taxonomic units (OTUs) in mountain meadows (619) accounted for 38.98% of the total OTUs; the number of fungal OTUs in temperate steppe (512) accounted for 32.24% of the total OTUs; and the number of fungal OTUs in temperate deserts (457) accounted for 28.78% of the total OTUs. After exclusion (Fig. 2B), the number of fungal OTUs in mountain meadows and temperate steppes decreased by 18.1% and 18.36%, respectively, compared with those before exclusion, but the number of fungal OTUs in temperate deserts increased by 38.51% compared with those before exclusion. In the 5-10 cm soil layer (Fig. 2C), the number of fungal OTUs in mountain meadows (512) accounted for 32.04% of the total OTUs; the number of fungal OTUs in temperate steppes (596) accounted for 37.30% of the total OTUs; and the number of fungal OTUs in temperate deserts (490) accounted for 30.66% of the total OTUs. After exclusion (Fig. 2D), the number of fungal OTUs in temperate steppes decreased by 20.47% compared with that before exclusion, while the number of fungal OTUs in mountain meadows and temperate deserts increased by 2.7% and 15.71%, respectively, compared with that before exclusion.