A Case for Silicon Fertilization to Improve Crop Yields in Tropical Soils

Long period of intensive crop cultivation deplete the available soil silicon (Si). Depletion of available Si in the soil could be one of the possible limiting factors amongst others contributing to declining yields. The lower values for Si in the soil can be justified due to (i) severe and frequent soil erosion and sediment transportation. (ii) Usually plants absorb Si almost equal to the concentration of most of macronutrients. (iii) Due to the desilication process, Si in the soil is continuously lost as the result of leaching process. Subtropical and tropical soils are generally low in available Si and would benefit from Si fertilization. The silicon content in some regions might be limited to sustainable crop production. Hence, improved Si management to increase yield and sustain crop productivity appears to be necessary in temperate as well in tropical countries. In order to address this problem of yield decline or stagnation, it seems necessary to survey the Si status of agriculturally important soils of different parts of the country and develop region-specific integrated nutrient management systems that include the Si element.