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于2012年4—10月逐月月末采集重庆缙云山4种典型林分(常绿阔叶林、毛竹林、针阔混交林和针叶林)样地中不同深度(0~15、>15~30、>30~60 cm)的土壤样品,测定土壤中w(TN)、w(NH4+-N)和w(NO3--N),分析土壤氮素含量的分布特征,并探讨土壤理化性质对土壤氮素含量的影响.结果表明:1不同林分土壤中氮素含量的垂直分布规律相一致,均表现为随土壤深度的增加而不断降低,并且w(NH4+-N)>w(NO3--N);2不同林分0~60 cm土壤平均氮密度表现为毛竹林(1.037 kg/m2)>针阔混交林(0.783 kg/m2)≈常绿阔叶林(0.778 kg/m2)>针叶林(0.747 kg/m2);3不同林分土壤中w(TN)的季节性变化规律不明显,而w(NH4+-N)和w(NO3--N)的季节性变化规律相似,均表现为春季<夏季<秋季;4不同林分土壤中w(TN)、w(NH4+-N)和w(NO3--N)与容重、w(SOC)均呈显著线性相关(P<0.05),而且与土壤其他养分含量之间也存在一定的相关性.
From April to October in 2012, the soil samples collected from four typical stands (evergreen broad-leaved forest, moso bamboo forest, coniferous and broad-leaved mixed forest and coniferous forest) at different depths (0-15,> 15 ~ 30,> 30 ~ 60 cm) soil samples were collected to determine the distribution characteristics of soil nitrogen, w (NH4 + -N) and w (NO3 - N) The results showed that: 1. The vertical distribution of nitrogen in different forest stands was consistent with the decreasing of soil depth, and the ratio of w (NH4 + -N)> w (NO3- -N); 2 The average nitrogen density in 0 ~ 60 cm soil layer in different stands was 1.037 kg / m 2 for the bamboo forest> 0.783 kg / m 2 for the broad-leaved forest> 0.778 kg / m 2> (0.747 kg / m2). The seasonal variations of w (TN) in three stands differed from each other, while the seasonal changes of w (NH4 + -N) and w (NO3 - N) The results showed that there was a significant linear correlation between w (SOC) and w (SOC), w (NH4 + -N) and w (SOC) ), But also some correlation with other soil nutrient contents.