BioSiSol

Recent studies have suggested that land use and particularly agriculture can modify the Si cycle through a depletion of soil available Si. The extent of the perturbation is not known yet but may be a critical factor for maintaining high yields of crops that are Si accumulators i.e. most of the cereals. Albeit generally not considered as an essential element, Si is presently used as a fertilizer in a few countries including Japan, China, South America and USA (Florida) essentially to overcome the depletion of the bioavailable Si in rice cultivation. Si can also be beneficial for crop growth under environmental stress such as water deficit. Therefore, it is relevant to handle the question of the role of Si in the French agriculture considering the importance of crop production where cereals are cultivated half of the arable soils. The aim of the proposal is to determine the status of bioavalaible Si in French soils and to model the Si requirement by crops as a function of agricultural practices (straw exportation, Si fertilization) and climate change (water stress) at the decadal to centennial-scale durations. Wheat cultivation has been choosen considering its importance in French agriculture. The consortium is composed of 4 partners from the French public reseach that have the complementarity required for identify and quantify the Si status in plant and soils. We will apply a multidisciplinary approach combining macroscopical and microscopical analyses of soils and plants, field and laboratory experiments, isotope (d30Si), pseudo-isotope (Ge/Si) biogeochemistry and mechanistic modeling. We will benefit from the existing infrastructure of the French banks of soil samples and of wheat varieties. The present proposal is expected to provide with innovative concepts that may be useful for a better management of cultivated soils.