Disease response and silicon concentration in rice in Italy

Rice is a silicon (Si) accumulator and the plant benefits from Si nutrition. Silicon application increases rice yield and has direct and indirect beneficial effects on the rice grown. Different Si sources are available as fertilizer but some characteristics as high content of available Si, low cost and low content of heavy metal reduce the number of products able to be used. This work was aimed to analyze the effects of calcium silicon slag on rice production and on Brown spot, a disease strictly linked with Akiochi incidence, that is largely diffuse in some Italian sandy soils. An experimental trial was set up with treatments including no amendment and calcium silicon slag at different rates up to 1 ton/ha Calcium silicon slag was fully characterized, soil samples were analyzed for Si extractable in water and in 1 M sodium acetate buffered at pH 4. Y leaves, straw and rice husks were analysed for total Si content. Yield, Brown spot disease incidence and were also determined. The soil and the plant Si content resulted lower than the deficiency limit. So the large incidence of Brown spot can be attributed to Si deficiency. Yield, Si extractable in water and Si content of plants was not increased by the fertilizer addition while Si extractable in sodium acetate increased significantly. Identification of more efficient fertilizers seem to be a priority.