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中国西南喀斯特地区土壤营养元素流失形势严峻,揭示不同土地覆被下土壤CO2-C的释放规律,是认识喀斯特这一特殊环境诸多营养元素循环问题的一个重要途径。采用静态箱-气相色谱法对贵州喀斯特地区4种不同土地覆被下的土壤CO2-C释放通量进行观测研究。结果表明,(1)不同的土地覆被下土壤CO2-C释放通量有显著的差别,其释放顺序为:森林((134.1±78.8)mg/(m2·h))>次生林((70.8±122.3)mg/(m2·h))>玉米地((55.5±78.0)mg/(m2·h))>烧荒地((35.5±91.4)mg/(m2·h))。各样点季节变化都比较明显,夏季平均排放量最高,冬季最低。(2)凋落物对森林土壤CO2-C释放的影响较大,有凋落物覆盖的土壤CO2-C释放量((134.1±78.8)mg/(m2·h))高于无凋落物覆盖的林地土壤((111.2±80.3)mg/(m2·h)),凋落物分解对森林土壤CO2-C释放总量的贡献约占17%。基于地面气温,计算得出森林和森林(无凋落物)的Q10分别为1.92、2.10。(3)除次生林和烧荒地外,其余各样地CO2-C释放通量均与土壤各层温度呈显著正相关关系,但绝大多数样地与土壤湿度(WFPS)之间相关性不显著。
The loss of soil nutrient elements in the karst area of Southwest China is severe, revealing the release of soil CO2-C under different land cover is an important way to understand the circulation of many nutrient elements in karst special environment. The CO2-C fluxes of soil under four different land coverings in Guizhou karst area were observed by static box-gas chromatography. The results showed that: (1) There was a significant difference in soil CO2-C fluxes under different land coverings, with the order of release: forest ((134.1 ± 78.8) mg / (m2 · h) 122.3 mg / (m2 · h))> corn land ((55.5 ± 78.0) mg / (m2 · h))> wasteland (35.5 ± 91.4 mg / (m2 · h)). The seasonal changes of all kinds of spots are obvious, with the highest average summer discharge and the lowest winter. (2) The effect of litterfall on CO2-C release from forest soils was larger. The CO2-C release from litter covered soil was higher (134.1 ± 78.8 mg / (m2 · h)) than that of litter-covered forest Soil ((111.2 ± 80.3) mg / (m2 · h)), litter decomposition contributed about 17% to the total amount of CO2-C released by forest soils. Based on the surface air temperature, the Q10 of forests and forests (no litter) were calculated to be 1.92 and 2.10, respectively. (3) There was a significant positive correlation between CO2-C flux and soil temperature except for secondary forest and burning wasteland, but there was no significant correlation between WFPS and most of the plots. .