Abstract
The recognition of the soil-root interface as a zone of high microbial activity is over a century old, but a rational and evidence-based confi - dence in the possibility of its manipulation is much more recent. Today the major emphases in fundamental rhizosphere research are towards describing microbial diversity, translating the chemical language that plants and microbes use and deciphering how the soil properties infl uence communication. Successful modifi cation of the rhizosphere for plant growth promotion and the retention or recovery of soil quality will be dependent on a clear appreciation of the many and often subtle relationships that plants have with each other as well as with the vast numbers of harmful and benefi cial soil microbes in their vicinity. Th e rapidly growing catalogue of plant and microbial genomes and a fast-expanding knowledge of how signals are generated and perceived are playing a big part in our improving understanding. Also important is an acceptance that plant-microbe relationships have co-evolved and are continuing to do so as land use, agricultural practices, soil quality, climate and crop selection change. Albert Rovira's writings over the past 50 years have played a major role in our exploration and explanation of the rhizosphere. His contributions are as varied as they are profound and encompass technical advances and experimental investigations of the rhizosphere (root exudates, microbial enumeration, ultrastructure, nutrient accession, virulence factors, etc.) as well as applied aspects closely related to plant health and soil fertility (biological control of fungal pathogens and nematodes, ammonifi cation and nitrifi cation, pesticide aff ects, soil structure, climatic impacts, soil management, etc.). Rovira's research is that rare combination of fundamental studies and their successful application to the real (and often harsh) world of agriculture. Some of the many ways in which Albert Rovira's discoveries and ideas have provided signposts for current investigations and, ultimately, for accomplishing the sustainable management of soil are summarised in this article.