3.5 Three-way ANOVA analysis
The output of the three-way ANOVA indicated significant effects of the heat, drought, and the combined heat and drought treatments on eight characteristic indexes in the four alpine meadow species. Height was significantly affected by species (P <0.05) and heat (P <0.01). The LWC and AGB were significantly affected by the height, species, drought and heat interaction, and drought, heat, and species interaction (P <0.01). The LWC was relatively weakly affected by drought (P <0.05). The effect of six of the seven treatments on BGB was non-significant.. Except for species, Pn was significantly affected by the other single and compound factors (P <0.01). The effect of compound factors was more significant than that of single factors on Tr (P <0.01). Except for height and the drought and height interaction, Gs was significantly affected by the other single and compound factors (P <0.01). Ci was significantly affected by seven factors, with the species, drought and species interaction, height and species interaction, and drought, height, and species interaction having extremely significant effects (P <0.01) (Table 4).