• 关键词：生物结皮  土壤CO₂通量  温度敏感性  Q₁₀  侵蚀区

• 基金项目：国家自然科学基金项目(No.41171422,40971174);中国科学院战略性先导科技专项(No.XDA05050504);中国科学院知识创新工程重要方向性项目(No.KZCX2-YW-443)

• 王爱国
• 1. 西北农林科技大学林学院, 杨凌 712100;
  2. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100

• 赵允格
• 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100

• 许明祥
• 1. 西北农林科技大学林学院, 杨凌 712100;
  2. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100

• 王一贺
• 1. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100;
  2. 中国科学院大学, 北京 100049

• 杨丽娜
• 1. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100;
  2. 中国科学院大学, 北京 100049

• 明姣
• 1. 西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100;
  2. 中国科学院大学, 北京 100049

• 摘要：利用LI-8100 土壤碳通量自动观测系统监测了黄土高原不同侵蚀区(水蚀区、水蚀风蚀交错区、风蚀区)生物结皮土壤CO₂通量的日变化,分析了土壤呼吸的温度敏感性.结果表明:以去除生物结皮为对照,具有生理活性的生物结皮降低了土壤CO₂通量,其中,水蚀区、交错区和风蚀区土壤日平均CO₂通量分别降低了5.0%、8.9%和20.5%.水蚀区、交错区和风蚀区生物结皮土壤CO₂通量日动态均呈单峰型曲线,峰值出现在12:00—14:00左右,大小分别为1.64、1.64和1.37 μmol·m^-2·s^-1,但日变化幅度差异明显.土壤呼吸速率随温度的升高呈上升趋势,指数函数能够较好地描述二者的关系.生物结皮土壤呼吸的温度敏感性指数Q₁₀在空间尺度上存在一定变异,其中,水蚀区、交错区Q₁₀值变化范围为1.93~2.43,而风蚀区Q₁₀值变化范围为4.80~5.56,说明风蚀区生物结皮土壤呼吸对温度的敏感性大于水蚀区和交错区.本研究表明,在探求黄土高原地区土壤碳交换时,应当考虑生物结皮的影响及不同侵蚀区生物结皮土壤CO₂通量的差异性.

• Abstract：Biological soil crusts (biocrusts), as ubiquitous living covers on soil surface in arid and semi-arid regions, exerted a potential effect on soil CO₂ flux. In the study, the diurnal dynamic of soil CO₂ flux of biocrusts in different erosion regions (water erosion region, water-wind alternated erosion region and wind erosion region) on the Loess Plateau was measured by LI-8100 automated soil CO₂ flux system and the temperature sensitivity of soil respiration was analyzed. The results showed that CO₂ flux of soil with activated biocrusts decreased compared with the flux without biocrusts in the three regions. The daily soil CO₂ flux with biocrusts was reduced by 5.0%, 8.9% and 20.5% in the water erosion region, water-wind alternated erosion region and wind erosion region, respectively. The soil CO₂ fluxes in the daytime showed a simple peak curve. The peak fluxes were observed during 12:00—14:00. The value of CO₂ flux in the water erosion region, the water-wind alternated erosion region and the wind erosion region was 1.64, 1.64 and 1.37 μmol·m^-2·s^-1, respectively. Soil respiration rate increased along with the rising temperature, and the relationship can be described by an exponent model. The range of temperature sensitivity quotients (Q₁₀) was changed between 1.93 and 2.43 in the water erosion region and in the water-wind erosion region while the range of Q₁₀ values was 4.80~5.56 in the wind erosion region, which indicated that the effect of temperature on biocrusts soil respiration in the wind erosion region was more sensitive than that in the water erosion region and the water-wind erosion region. The study suggested that the effect of biocrusts on soil CO₂ flux should be taken into consideration when discussing the soil carbon exchange on the Loess Plateau.

• Key words：biocrusts  soil CO₂ flux  temperature sensitivity  Q₁₀  erosion region

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