土壤植硅体碳稳定性的研究进展与展望

植硅体碳（phytolith-occluded organic carbon, PhytOC）是一个重要的长期（数千年）陆地碳组分，从而成为陆地土壤长期固碳的重要机制之一。植硅体碳的稳定性对全球陆地土壤碳库贡献比植硅体碳储量要大得多。综述了土壤植硅体碳的形成机制与特征，研究植硅体碳稳定性的重要意义以及影响植硅体碳稳定性的因素:不同植被类型产生的植硅体碳的稳定性存在显著差异，不同生长环境下同一植被类型的植硅体碳稳定性也存在差异；古土壤中的植硅体碳稳定性大于幼年中的土壤；植物植硅体的形态组合能够响应土壤盐碱浓度及pH值的变化；湿度和降水等影响植硅体的数量、大小、形态组合以及碳、氧同位素；大气二氧化碳浓度对植硅体的类型、大小比率等产生影响；植硅体的硅铝比值越低，稳定性越高。表1参90

Research progress and forecast of phytolith-occluded organic carbon stability in soil

As an important long-term terrestrial carbon fraction, the phytolith-occluded organic carbon (PhytOC) has become an important mechanism in the long-term terrestrial carbon sequestration. The contribution of PhytOC stability to the global terrestrial soil carbon pool is much greater than PhytOC stocks. The paper reviewed the formation mechanism and characteristics of PhytOC, the significance of studying the PhytOC stability, and the determinants of the PhytOC stability. PhytOC produced from different types of vegetations had significantly different stability. PhytOC produced from the same type of vegetations but under different growth environments also had different stability. The PhytOC in ancient soil was more stable than that in young soil. The morphological combinations of phytolith in plants were able to respond sensitively to saline-alkali concentrations and pH values in soil. The humidity and precipitation could affect the quantity, size, morphology, assemblages δ13C and δ18O of phytolith. The smaller the Si/Al ratio of phytolith was, the higher the stability would be.[Ch, 1 tab. 90 ref.]