Microbial N turnover and N-oxide (N2O/NO/NO2) fluxes in semi-arid grassland of Inner Mongolia
Microbial N turnover and N-oxide (N2O/NO/NO2) fluxes in semi-arid grassland of Inner Mongolia
复制标题
DOI：
10.1007/s10021-007-9043-x
复制
发表时间：
2007-06-01
期刊：
影响因子：
3.7
通讯作者：
Han, Xingguo
中科院分区：
文献类型：
--
作者：
Holst, Jirko;Liu, Chunyan;Han, Xingguo
在内蒙古锡林河流域不同放牧和未放牧的草原样地，测定了土壤氮素矿化和硝化的总速率以及N2 O、NO和NO2的土壤-大气通量。中国，在2004年和2005年的生长季节。实验地点是自1979年以来未放牧的地块（UG 79），自1999年以来未放牧的地块（UG 99），冬季适度放牧的地块（WG）和过度放牧的地块（OG），所有这些地块彼此非常接近。在原位土壤水分和土壤温度条件下测定的氮素矿化和硝化的总速率在0.5-4.1 mg N kg（-1）上标停止土壤干重日（-1）的范围内。在2005年，总氮周转率显着高于UG 79地块比UG 99地块，这反过来又显着高于WG和OG地块的总氮周转率。WG和OG情节没有显着差异，总氨化和总硝化速率。在SOC含量，容重和质地的网站差异可以解释只有不到15%的总氮周转率观察到的网站差异。N2 O和NO（x）通量在两个生长季节都很低。没有显着差异，N示踪气体通量之间的地块。N2 O通量的平均值在0.39和1.60 μ g N2 O-N m（-2）h（-1）之间变化，相当于0.03-0.14 kg N2 O-N ha（-1）y（-1），大大低于同一区域以前报告的数值。NO（x）通量率在0.16和0.48 μ g NO（x）-N m（-2）h（-1）之间，分别相当于0.01-0.04 kg NO（x）-N ha（-1）上标stop y（-1）。N2 O排放通量与土壤温度和土壤湿度呈显著正相关。然而，相关性只能解释不到20%的通量方差。
Gross rates of N mineralization and nitrification, and soil-atmosphere fluxes of N2O, NO and NO2 were measured at differently grazed and ungrazed steppe grassland sites in the Xilin river catchment, Inner Mongolia, P. R. China, during the 2004 and 2005 growing season. The experimental sites were a plot ungrazed since 1979 (UG79), a plot ungrazed since 1999 (UG99), a plot moderately grazed in winter (WG), and an overgrazed plot (OG), all in close vicinity to each other. Gross rates of N mineralization and nitrification determined at in situ soil moisture and soil temperature conditions were in a range of 0.5-4.1 mg N kg(-1) supercript stop soil dry weight day(-1). In 2005, gross N turnover rates were significantly higher at the UG79 plot than at the UG99 plot, which in turn had significantly higher gross N turnover rates than the WG and OG plots. The WG and the OG plot were not significantly different in gross ammonification and in gross nitrification rates. Site differences in SOC content, bulk density and texture could explain only less than 15% of the observed site differences in gross N turnover rates. N2O and NO (x) flux rates were very low during both growing seasons. No significant differences in N trace gas fluxes were found between plots. Mean values of N2O fluxes varied between 0.39 and 1.60 mu g N2O-N m(-2) h(-1), equivalent to 0.03-0.14 kg N2O-N ha(-1) y(-1), and were considerably lower than previously reported for the same region. NO (x) flux rates ranged between 0.16 and 0.48 mu g NO (x) -N m(-2) h(-1), equivalent to 0.01-0.04 kg NO (x) -N ha(-1) supercript stop y(-1), respectively. N2O fluxes were significantly correlated with soil temperature and soil moisture. The correlations, however, explained only less than 20% of the flux variance.