Liu Fang, Liu Cong-qiang, Wang Shi-lu, Lü Ying-chun
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
Ying Yong Sheng Tai Xue Bao. 2008 Aug;19(8):1829-34.
By using close chamber-GC method, the N2O fluxes in de-farming grassland, bush land, Pinus massoniana forestland, and broadleaved forestland in central Guizhou were measured in situ in 2006 and 2007 to investigate the seasonal change patterns of soil N2 O flux under different vegetations in karst region of southwest China. The results indicated that in a whole year round, the soils in all test sites played the source of atmospheric N2O, only acting as a N2O sink in exceptional months. The soil type and the vegetation had obvious effets on the N2O flux from soil. Yellow soil had a smaller N2O flux than calcareous soil, except for broadleaved forestland. The N2O fluxes from de-farming grassland and bush land were higher in spring and lower in autumn and winter, and varied within the range of -20.7 - 103.09 microg N x m(-2) x h(-1) and -33.0-67.3 microg N x m(-2) x h(-1), respectively; while those from P. massoniana forestland and broadleaved forestland were the highest in spring but had no definite change patterns in other seasons, and varied within the range of -5.3 - 35.0 microg N x m(-2) x h(-1) and -14.4 - 152.8 microg N x m(-2) x h(-1), respectively. The correlation analysis showed that there existed a negative correlation between soil moisture content and N2O flux, suggesting that soil moisture was the main factor driving the seasonal change of N2O flux. Temperature indirectly affected the soil N2O flux through affecting soil moisture.
采用密闭箱-气相色谱法，于2006年和2007年对贵州中部退耕草地、灌丛地、马尾松林林地和阔叶林林地的N2O通量进行了原位测定，以研究中国西南喀斯特地区不同植被下土壤N2O通量的季节变化规律。结果表明，全年各试验点土壤均为大气N2O的源，仅在个别月份为N2O汇。土壤类型和植被对土壤N2O通量有明显影响。除阔叶林林地外，黄壤的N2O通量低于石灰土。退耕草地和灌丛地的N2O通量春季较高，秋冬较低，变化范围分别为-20.7～103.09μg N·m-2·h-1和-33.0～67.3μg N·m-2·h-1；而马尾松林林地和阔叶林林地的N2O通量春季最高，其他季节变化无规律，变化范围分别为-5.3～35.0μg N·m-2·h-1和-14.4～152.8μg N·m-2·h-1。相关性分析表明，土壤含水量与N2O通量呈负相关，说明土壤水分是驱动N2O通量季节变化的主要因素。温度通过影响土壤水分间接影响土壤N2O通量。
