Angelia L. Seyffertha c 
Benjamin D. Kocarb Jessica A. Leec Scott Fendorfc. Seasonal dynamics of dissolved silicon in a rice cropping system after straw incorporation.Geochimica et Cosmochimica ActaVolume 123 15 December 2013 Pages 120–133
Abstract
Rice is an important staple for over half the world’s population and silicon (Si) is a vital nutrient that helps to improve yields through its role in alleviating biotic and abiotic stresses. Despite Si being abundant in crustal materials it is only slowly released to soil pore-waters through chemical weathering. However biocycling of Si through plant material (i.e. phytoliths) and back into soil is comparatively rapid and thus may exert a dominant control on the biogeochemical cycling of Si within soils and near-surface sediments in some environments. Despite the potential importance of this pathway Si cycling is poorly resolved in cultivated systems such as rice cropping. Here we monitored seasonal trends of Si in pore-water plants and soil over a two-year period in a California rice cropping system where straw is incorporated into the soil during the fallow season. There was a clear seasonal trend of high pore-water Si concentrations during the winter fallow that approached predicted equilibrium with amorphous Si followed by low concentrations during the growing season within the top 20 cm of the profile. The seasonal change in Ge-Si ratios from low values during the winter fallow to high values—up to 36 μmol