Arbuscular mycorrhizal fungal community of wheat under long-term mineral and organic amendments in semi-arid Mediterranean Turkey

A minimal amount of information is currently available concerning arbuscular mycorrhizal (AM) fungal associations with crops in semi-arid zones on Leptosols in Turkey. Therefore, using molecular ecological techniques, we studied the effects of different management practices (without fertilization, chemical fertilization, farmyard manure, and plant compost amendments) on AM fungal communities associated with wheat roots. Experiments were conducted in a field established in 1996 in southern Mediterranean Turkey where soil productivity is low owing to unfavorable climatic effects and soil characteristics. We determined 201 partial sequences of AM fungal nuclear ribosomal large subunit genes. The higher AM fungal richness was found in the control treatment without fertilization and plant compost treatments compared with the chemical fertilization and farmyard manure treatments. Clones related to Rhizophagus were found in all treatments and accounted for 37% of the total AM fungal clones, whereas those of Funneliformis were dominant under chemical fertilization. Redundancy analysis based on the frequency of operational taxonomic units revealed that AM fungal communities were divided into three groups, namely, the control treatment, the chemical fertilization treatment, and the organic treatments (farmyard manure and plant compost treatments). Although different organic amendments supported relatively similar AM fungal communities, plant compost induced higher AM fungal richness than farmyard manure fertilization.