Determining the Effects of Silicon Content in Rice Husk Biochar of Southern Taiwan on the Germination of Corn Seeds (Zea mays L.)

Abstract

To our knowledge, not many investigations about this topic have been done in Southern Taiwan, where the potential of rice residues from agriculture fields is abundant. Farmers are not aware that they could improve crop production and increase stress and disease resistance by adding a source of available silicon to the soil. Still, reports on the Si effect of rice husk biochar on plant seed germination are scant. In line with the above, the objective of this study is to assess the potential effects of biochar from pyrolyzed rice husks on corn (Zea mays L.) seed germination and its effect on plant growth. Our purpose for those rice residues is to transform them into biochar. Our experiment was conducted in Pingtung County, where we studied the characteristics of rice husk biochar, applying different types of combustion and temperatures in the process, as well, the effects on corn (Zea mays L.) seed germination. The experimental trial was composed of seven (7) different treatments, including rice husk, rice husk biochar, and chemical fertilizer. The biochar treatments used a mixture of 50% biochar and 50% soil to balance the quantities of rice husk biochar that could be incorporated into clayey soils. The effect of biochar application on corn growth was evaluated. Results showed that silicon content in rice husk biochar could inhibit seed germination linearly. Silicon in this study was found to be harmful significantly to corn seed germination when Si content in rice husk biochar was higher than 25 to 30 wt%, indicating that increased levels of silicic acid and quantities of the amendment above 8-10 tons per hectare can reduce the germination rate. The most promising effect is the apparent reduction in the total availability contents of heavy metals in bottom ash, suggesting that using binary mixtures in vegetation production is safe.