伏牛山3种典型针叶林植硅体碳的封存特性及稳定性比较研究

Storage and Stability of Phytolith-occluded Carbon in Three Typical Coniferous Forests at Mt.Funiu

【目的】通过对伏牛山3种针叶林植物器官、枯落物和土壤中植硅体及植硅体碳的研究,探讨不同林分间植硅体碳的封存特性及稳定性差异,为长期固碳提供理论依据。【方法】在伏牛山的雪松(Cedrus deodara)、圆柏(Sabina chinensis)、侧柏(Platycladus orientalis)3种森林中对植物各器官、枯落物和0~50 cm深的土壤剖面进行采样,基于质量平衡法研究了土壤与植物体内的植硅体、植硅体碳和二氧化硅(SiO_(2))的含量。【结果】雪松各器官植硅体含量在1.49~3.27 g·kg^(−1),植硅体碳含量在0.030~0.114 g·kg^(−1)。圆柏各器官植硅体含量在1.44~2.56 g·kg^(−1),植硅体碳含量在0.036~0.085g·kg^(−1)。侧柏各器官植硅体含量在1.86~2.90 g·kg^(−1),植硅体碳含量在0.038~0.083 g·kg^(−1)。本研究估算了植硅体碳在各林分中的生产通量与周转时间,圆柏林中土壤植硅体碳储量(1.64 t·hm^(−2))高于雪松林(1.17 t·hm^(−2))和侧柏林(0.77 t·hm^(−2)),且圆柏林植硅体碳周转时间(1813.16 a)长于雪松林(218.78 a)和侧柏林(556.44 a)。【结论】不同的森林类型对植硅体及植硅体碳的生产速率和周转时间会有显著影响,在未来的针叶林森林管理计划中优化圆柏的造林/再造林会显著增强未来几个世纪的生物地球化学碳汇。

【Objective】Sequestration and stability of phytoliths and phytolith-occluded carbon(PhytOC)in plant organs,ground litter,and soil in three typical coniferous forests at Mt.Funiu in Henan province were analyzed to better understand the long-term carbon fixation in the eco-system.【Method】Contents of phytoliths,C in phytoliths,PhytOC,and SiO_(2)in the plant organs,ground litter,and 0-50 cm soil in Cedrus deodara,Sabina chinensis,and Platycladus orientalis forests at Mt.Funiu were collected according to the mass balance method.【Result】The contents of phytoliths,C in phytoliths,PhytOC,and SiO_(2)in various organs of the trees and soil of the forests in the area varied significantly.The phytolith contents in the plant organs ranged 1.49-3.27 g·kg^(−1)for C.deodara,1.44-2.56 g·kg^(−1)for S.chinensis,and 1.86-2.90 g·kg^(−1)for P.orientalis,while the PhytOC at the C.deodara forest,0.030-0.114 g·kg^(−1),at the S.chinensis forest,0.036-0.085 g·kg^(−1),and at the P.orientalis forest,0.038-0.083 g·kg^(−1).The production fluxes estimated by this study indicated that the soil PhytOC storage at the S.chinensis forest was 1.64 t·hm^(−2),which was higher than 1.17 t·hm^(−2)at the C.deodara forest and 0.77 t·hm^(−2)at the P.orientalis forest.The estimated PhytOC turnover time for the S.chinensis forest soil was 1813.16 a,which was significantly longer than 218.78 a for the C.deodara forest soil or 556.44 a for the P.orientalis forest soil.【Conclusion】Significant variations existed on the phytolith content in the plant organs and the PhtyOC production rate and turnover time of the soil at the 3 forests.By optimizing and/or re-establishing the coniferous S.chinensis forest in the mountain,the biogeochemical carbon sink of the environment could be significantly enriched.