Distribution of arbuscular mycorrhizal fungi in sugarcane rhizosphere from various agricultural management practices in Northeast, Thailand

Abstract

Sugarcane (Saccharum spp.) is one of the economically most important crops in Thailand. Sugarcane forms symbiotic associations with arbuscular mycorrhizal fungi (AMF). Species diversity of and root colonization by AMF may vary by agricultural management and soil properties. The objective of this study was to investigate the community composition of AMF in sugarcane rhizosphere soil with various cultivation practices. Twelve sugarcane rhizosphere soils were collected from sugarcane fields in three provinces (Nakhon Ratchasima, Khon Kaen, and Buri Ram) with various forms of agricultural management, including organic farming (OM), semi-organic farming (SM), and conventional farming with mineral fertilizers (CM). The results showed that root colonization ranged between 10 and 22%, while spore density ranged from 11 to 168 spores 100 g soil-1. Based on morphological identification of AMF, a total of 43 taxa, representing 11 genera, were observed, viz. the genera Acaulospora, Claroideoglomus, Dentiscutata, Diversispora, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizophagus, and Septoglomus. One unidentified species was found. The dominant genera were Acaulospora and Glomus, which were found in all sites. Diversispora pustulata was the most widely distributed species, isolated in 75% of the sites. Species diversity of AMF, expressed by Shannon–Wiener index of diversity (H’), ranged from 1.03 to 2.14 with the highest diversity in OM systems and lowest diversity in CM systems. Our results may be used for considerations of agricultural management practices to benefit from communities of native AMF, which could be important for sustainable production of sugarcane.