| 摘要: |
| 【目的】研究黄土丘陵区刺槐林不同土层土壤碳通量，以准确评估该区域土壤碳排放量。【方法】以坡耕地(对照)以及10，20，30和40年生的刺槐(Robinia pseudoacacia)林为研究对象，用气体井法测定CO2浓度，使用Fick扩散法(5种扩散系数模型)计算0～200 cm土层土壤剖面碳通量，并用Li-8100腔室法对表层土壤碳通量进行实地监测，最后将黄土丘陵区刺槐林地不同深度土层土壤碳通量的估算结果与实测值进行对比分析。【结果】1)5种扩散系数模型对土壤剖面碳通量的模拟结果有较大差异，其中Penman模型计算结果与实测值差异最大，Moldrup模型计算值与实测值差异最小。2)5种扩散系数模型计算的土壤碳通量均大于实测值，但与实测值均具有显著相关性(P＜0.05)。3)在黄土丘陵区刺槐林地0～20，80～140，200 cm土层估算土壤碳通量的最佳扩散系数模型分别为Moldrup-2000、Moldrup-1997和Millington模型。4)在黄绵土0，20，80，140，200 cm土层，土壤CO2扩散系数分别为0.15，0.14，0.20，0.22和0.27，据此计算的各土层土壤碳通量分别为0.72，0.32，0.30，0.24和0.17 μmol/(m2·s)，可见随着土层深度的增加，土壤碳通量逐渐降低。【结论】黄土丘陵区不同刺槐林地各土层的环境因子有一定差异，所以估算不同深度土壤碳通量的最佳模型有所区别；研究确定的黄土区不同土层碳通量估算模型和气体扩散系数模型中的各种参数，对于准确评估区域土壤碳排放具有重要参考价值。 |
| 关键词: 黄土丘陵区 刺槐林地 土壤碳通量模型 扩散系数 |
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| 基金项目:国家自然科学基金项目(41171228)；中科院战略性先导科技专项子课题(XDA05050504)；中科院知识创新重要方向项目(KZCX2-YW-443) |
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| Modeling soil CO2 flux of Robinia pseudoacacia woodland in the Loess Hilly Region |
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DONG Li-ru,XU Ming-xiang,SUN Hui
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| Abstract: |
| 【Objective】This study explored the carbon fluxes at different soil layers of Robinia pseudoacacia woodland in the Hilly Loess Region,to accurately assess soil carbon emissions in this region.【Method】Crop land (the control) and black locust (Robinia pseudoacacia) woodlands with different ages (10,20,30,and 40 years) were selected.CO2 concentration in each soil layer was measured by gas-well method,CO2 flux of 0-200 cm soil profile was calculated using Fick diffusion method,and Li-8100 chamber method was used to monitor the surface soil carbon flux.At last,the predicted and measured soil carbon fluxes were compared and analyzed.【Result】1) Carbon fluxes simulated by the five diffusion models showed big differences.Moldrup model was the best whereas Penman model was the poorest.2) Simulated carbon fluxes by the five diffusion models were all higher than the measured values with significant correlations (P＜0.05).3) The optimal models for simulating soil carbon fluxes at layers of 0-20,80-140,and 200 cm were Moldrup 2000,Moldrup-1997 and Millington-1961,respectively.4) The soil CO2 diffusion coefficients at soil depths of 0,20,80,140 and 200 cm were 0.15,0.14,0.20,0.22 and 0.27,respectively,and the estimated CO2 fluxes were 0.72,0.32,0.30,0.24 and 0.17 μmol/(m2·s), respectively.Soil carbon flux decreased as the increase of soil depth in the studied woodlands.【Conclusion】The best models for simulating soil carbon fluxes at different soil layers were different due to the differences in environmental factors in different soil depths of different Robinia pseudoacacia woodlands in the Hilly Loess Region.The research identified optimal soil carbon flux models and their parameters suitable for the Hilly Loess-Region,which improved the assessment of regional soil carbon emission. |
| Key words: Hilly Loess Region Robinia pseudoacacia woodland soil carbon efflux models diffusion coefficient |
