Diversity of Arbuscular Mycorrhizal Fungi in Oak-Pine Forests and Agricultural Land Prevalent in the Kumaon Himalayan Hills, Uttarakhand, India.

ABSTRACT

The diversity and abundance of arbuscular mycorrhizal fungi (AMF) was assessed in the Kumaon Himalayan foothills. Four typical ecosystems were selected in the Sat-Tal area located in the Nainital, district in Uttarakhand, India, representing vegetation change due to human settlement and selective logging of native oak. Besides a natural oak forest, a mixed pine-oak forest, a pure pine stand and an arable field were sampled. The latter was cropped with black gram (Vigna mungo L. Hepper) and maize (Zea mays L.) during the rainy season from June to September and rotated with wheat (Triticum aestivum L.) during winter for the last 10 years. Only cow dung compost used for fertilization. The highest AMF spore abundance throughout the year was recorded in soil samples from the pine-oak mixed forest, followed by the pine and oak forests and the agricultural field. At all sites, the lowest spore abundance was recorded at the end of the winter season in March, and the highest in October after the rainy season. Whereas in October, Glomus claroideum, Acaulospora scrobiculata and A. spinosa were found at all sites, in March it was only G. intraradices which occurred everywhere. The highest AMF spore morphotype richness was recorded in samples from the oak forest. In AMF-trap cultures set up with field soil inocula, the dominant species recovered were G. intraradices, G. etunicatum and A. scrobiculata. As compared to the field samples, trap culturing of one year enhanced spore abundance but entailed a loss of AMF richness. The study revealed differences in AMF community composition and structure among sites characterized by different land use systems.