2.5 Herbaceous plant diversity, fine root biomass, and AM fungal colonization rate survey
We explored herbaceous plant diversity in mid-July 2020. Three small randomly sample squares (1 m×1 m) were set in each sample square, the species of herbaceous plants, the number of individuals of the species (counted as a single plant in the above-ground part), height, and cover were investigated. The soil was collected at a depth of 0-15 cm using a soil auger, and the fine roots (<2 mm in diameter) of herbaceous plants were selected and their fine root biomass was measured(Li et al., 2021). We determined the AM fungal colonization rate of fine roots from herbs by a modified aniline blue staining method ((Zubek, Błaszkowski , & Mleczko, 2011).