The role of arbuscular mycorrhizal fungi in sustainable cropping systems

Mycorrhizal associations vary widely in structure and function, but the most ubiquitous interaction is the arbuscular mycorrhizal (AM) symbiosis. This interaction forms between the roots of over 80% of all terrestrial plant species and Glomeromycete fungi. This ancient symbiosis confers benefits directly to the host plants growth and development through the acquisition of phosphate and other mineral nutrients from the soil by the fungus, while the fungus receives a carbon source from the host. The symbiosis may also enhance the plant's resistance to biotic and abiotic stresses. Additionally, AM fungi develop an extensive external hyphal network, which makes a significant contribution to the improvement of soil structure. Therefore, these fungi constitute an integral and important component of agricultural systems. AM fungi are particularly important in organic farming systems and other sustainable systems which rely on biological processes, rather than agrochemicals, to supply nutrients and to control weeds, pests and diseases. The exploitation of AM fungi within sustainable cropping systems is dependent on a better understanding of the impact of agricultural management practices on AM fungal population dynamics and functioning. This review explores the links between AM fungi and agricultural management practices. © 2003 Elsevier Science B.V. All rights reserved.