Effect of Different Ecological Factors on Arbuscular Mycorrhizal Fungi in Rhizosphere of Shatian Pummelo

In this experiment, we investigated the impact of different habitats and seasons on mycorrhizal colonization of adult pomelo (Citrus grandis Osbeck. cv. Shatian You) trees and AM fungal spore density in rhizosphere soil. Results showed that both AM fungi colonization rate and spore density were highest in terraced field, and then follwed by sloping fields and lying land. In sloping fields or lying land, grassland had higher AM fungal colonization rate and spore density than no-tillage area. In different seasons, mycorrhizal colonization rate reached its highest value in summer, and then followed orderly by autumn, spring, and winter. Both the arbuscule and vesicles percentages were higher in summer/autumn than in spring/winter. While the number of AM fungi spores in rhizosphere soil reached its peak in autumn, then followed orderly by summer, spring, and winter. In conclusion, for adult pomelo trees, in terraced field, AM fungi infection rate reached its highest in summer, and AM fungal spore density reached largest in autumn. In sloping fields or lying land, both AM fungi colonization rate and spore density were improved significantly by sod culture.