2.6.1 Isolation and identification of AM fungal spores
The wet sieving method was used to obtain spores. The spores were placed under a stereomicroscope for count and observation. Then transferred spores to polyvinyl alcohol-lactic acid-glycerol (PVLG) with a pipette, and morphological characteristics were examined microscopically. It included spore color, shape, size, sporiferous saccule, spore wall thickness and type, subtending hyphae width and shape. The spores were identified according to the photos and feature and feature descriptions from VA mycorrhizal fungi identification manual (Schenck & Perez, 1990), INVAM (https://invam.ku.edu/), International AM fungal classification system (http://www.amf-phylogeny.com/).
AM fungal spore density, species richness, relative abundance (RA), frequency, importance value (I), and species alpha diversity index were calculated per 10 g of air-dried soil sample. The degree of AM fungal dominance was assigned into four categories according to their important values (I), I > 50% means dominant species, 30% < I ≤ 50% means subdominant species, 10% < I ≤ 30% means accompanying species and I ≤ 10% means rare species.