Interaction between soil properties and mycorrhizal status in different land use systems on lowland tropical forest areas of Sumatra (Indonesia)

Under most environmental conditions, trees and also other plants are naturally colonized by mycor-rhizal fungi. These mycorrhizal associations are highly complex and dynamic, a result of the great diversity of mycorrhizal fungi, hosts, and land use systems. The colonization of roots by mycorrhizal fungi can benefit the host by increasing nutrient and water uptake. In exchange, the host plant shares carbohydrate (carbon) from photosynthesis with the mycorrhizal fungi. A substantial portion of this carbon is often trans¬ferred to the rhizosphere and will improve the status of the soil organic matter. In tropical land, arbuscular mycorrhiza fungi (AMF) dominate in plant roots compared to ectomycorrhiza. Any change of the vegetation will influence the soil ecosystem directly through its litter, root exudation and root systems and indirectly through alteration in light, water, temperature and moisture conditions. Therefore, the aim of my study within the CRC 990 is to investigate the interaction of soil biogeochemical factors and plant nutrient status on the AMF in different land use system. The study is being conducted in forest and secondary forest with regenerating rubber (jungle rubber) and areas that have been converted from forests into monoculture plantations with rubber or oil palm plantations in two landscapes (Harapan and Bukit Dua Belas landscapes) that differ in soil texture.