Due to dessilication process, weathered soils (Alfisols,Inceptisols, Oxisols, Ultisols, etc.) of the sub-tropics and tropics (D'Hoore and Coulter, 1972) and problematic organic soils (Histosols) are most likely to be low or deficient in plant-available Si. They may not be able to support healthy and productive growth of crops that absorb relatively large
amounts of Si from soil. In other soils intensive cultivation of high yielding sugarcane cultivars having very short fallow
periods, may show signs of temporary depletion of bio-available Si. Decreasing
trends in yields of ratoon crops could be an example of the temporary depletion. In order to address these soil Si related issues, periodical Si status surveys of soils, plants and waters should be helpful for sustaining sugarcane yields over a long time. The better understanding of soluble or plant-available Si in soil during crop growth may assist formulating efficient region-specific integrated nutrient management systems for sugarcane.