作 者 ：孙文义,郭胜利*
期 刊 ：生态学报 2010年 30卷 10期 页码：2611~2620
Keywords:C, N, sequestration capacity, secondary forests, manmade forests, subsurface,
摘 要 ：研究深层土壤有机碳\,氮（Soil organic C，SOC，Total soil N，TSN）量对摸清陆地生态系统深层碳氮固定潜力，寻找碳汇丢失之谜和应对全球气候变暖具有重要意义。以黄土区子午岭林场3种典型人工林（油松、刺槐、小叶杨）和3种天然次生林（辽东栎、白桦、鼠李）为对象，在设立的18个样方内，分层测定了0-100 cm土层SOC、TSN和DOC（Dissolved organic C，DOC）量变化，监测了样方内地表长年凋落物积累量及其碳氮组成。1m土层内SOC、TSN和DOC含量天然次生林显著高于人工林。与人工林相比，天然次生林表层（0-20cm）SOC、TSN储量分别高42%、22%，但20-100cm土层SOC、TSN储量相对量最大。人工林下， 20-100cm土层SOC储量为33.6 t hm-2，占1m土层的55%；TSN储量为3.9 t hm-2，占1m土层的57%；天然次生林下， 20-100cm土层SOC、TSN储量分别为55.3 t hm-2、6.0 t hm-2，占1m土层储量分别为59%和63%。其中， 40-60cm天然次生林比人工林碳氮储量分别高了82%、65%；其次为20-40cm，天然次生林比人工林碳氮储量分别高了73%、65%。不同植被恢复条件下，SOC与DOC、TSN、Olsen-P都表现出较强的相关性。研究表明，植被恢复有利于土壤碳氮的积累，不仅表层土壤，深层土壤也具有较强的碳氮固定能力；天然次生林土壤碳氮固定能力和长年地表凋落物量都高于人工林。
Abstract:Exploring contents of soil organic C (SOC) and total soil N (TSN) in subsoil is crucial to finding out soil organic C and N sequestration potential in terrestrial ecosystem, the missing carbon sink and dealing with global warming. Data were presented on changes in soil organic C (SOC), total soil N (TSN) and Dissolved organic C (DOC) in three manmade forests (Pinus tabulaeformis, Robinia pseudoacacia, Pobulus simonii) and three secondary forests (Quercus liaotungensis, Betula platyphyllum, Rhamnus davurica) in Ziwuling site in hilly loess region, China. Eighteen sample plots were established to gather litter accumulation on aboveground and sample soils from 0-100cm soil profiles under different vegetation types at the hilly region. SOC, TSN and DOC in 0-100 cm soil layers and litter accumulation were determined to study soil organic C and N sequestration potential in subsoil under different vegetation. Storages of SOC, DOC and TSN of secondary forests were significantly higher than that in manmade forests. SOC and TSN sequestration quantity in surface soil (0-20cm) were 42% and 22% higher than that in manmade forests, respectively, but the relative C, N sequestration capacity in subsurface soil (20-100cm) were higher than that surface soil. For manmade forests, SOC storage （33.6 t hm-2）in 20-100cm soil layer account for 55% of the amount of 1m soil layers and the storage of TSN（3.9 t hm-2）in 20-100cm soil layer account for 57% of 1m soil layers respectively. For secondary forests, SOC storage (55.3 t hm-2) in 20-100cm soil layer account for 59% of 1m soil layers and TSN storage (6.0 t hm-2) in 20-100cm soil layer account for 63% of 1m soil layers. The relative storages of SOC and TSN in 40-60cm were increased by 82%, 65% respectively, followed by 20-40cm the relative storages of SOC and TSN were increased by 73%, 65%, respectively. With increasing of SOC under the different revegetation conditions, there is a strong correlation between SOC DOC, TSN, Olsen-P. The results suggested that revegetation could significantly enhance C and N sequestration capacity not only in surface soil but also in subsurface soil. Soil C and N sequestration capacity and litter accumulation under secondary forests were higher than that under manmade forests.
全 文 ：