Advancing our understanding of the dynamics of silicon at the soil-plant scale since Bartoli’s work (1980s)

Over the past thirty years, the silicon cycle at the scale of continental ecosystems has become an important topic within the scientific community. Since the 1990s, this research has been driven primarily by growing awareness of the need to quantify the impact of anthropogenic activities on the environment, as well as by advances in understanding the beneficial role of silicon in cultivated plants and its application in agricultural practices. This review highlights the major developments in the study of the silicon cycle at the soil-plant scale since the pioneering work of Bartoli, particularly his cycle model (Bartoli, F. Environ. Biogeochem. Ecol. Bull. 35 (1983), pp. 469–476). Phytoliths are now recognized as key players in the silicon cycle at both local and global scales. They represent a significant source of dissolved silicon (DSi), especially in highly weathered soils. Human activities such as deforestation, grazing, agriculture, and urban land use have been shown to disrupt the Si cycle. The concept of plant-available silicon indicator (PAS) has been developed and is now used alongside other routine soil parameters (e.g., pH and grain size) to identify the drivers of DSi. In the future, greater attention should be given to the determination and the dynamics of the available Si pools in plants, the quantification of the effects of biological factors other than plants, and the impact of atmospheric silicon inputs. The main factors influencing the terrestrial biogeochemical cycle of silicon should be integrated into models to predict the evolution of silicon in soils.