【摘要】 对祁连山北坡垂直带山地草原、森林、高山灌丛土壤有机碳和全氮的分布特征进行了研究,结果表明:土壤有机碳和全氮含量山地草原<青海云杉林<高山灌丛,表现为随海拔升高呈现上升趋势,且海拔3 100 m以上土壤碳、氮含量显著高于3 100 m以下土壤碳、氮含量;土壤有机碳和全氮在土壤剖面中的垂直分布大多表现为0~10 cm含量高于10 cm以下各层次的含量。土壤有机碳和全氮含量与土壤水分含量呈显著正相关(r=0.913,0.874,n=117,p=0.001),和年平均气温呈显著负相关(r=-0.883,-0.869,n=10,p=0.001),表明了气候因子对有机碳和全氮在垂直带上的空间分布起决定作用。整个垂直带土壤碳氮比在7.8~24.7间,有利于有机质矿化过程中养分的释放。作为祁连山北坡垂直带乔木林主体部分,青海云杉(Picea crassifolia)林土壤碳密度为18.13kg/m2,与一般常绿针叶林土壤碳密度相当,但远小于针叶林中的云冷杉林土壤碳密度。更多还原

【Abstract】 A study on soil organic(SOC) and total nitrogen(TN) was conducted in the mountainous grassland,Picea crassifolia forest and alpine shrubs along the altitudinal belts in the northern slope of Qilian Mountains,results showed that SOC and TN increased with elevation,in the order of mountain grassland<Picea crassifolia forest < alpine shrub,and SOC and TN above 3 100 elevation were much higher than that below the elevation gradient.Furthermore,SOC and TN mostly peaked at 10 cm soil depth along the soil profile.SOC and TN showed significant positive correlations with soil water content(r=0.913,0.874,n=117,p=0.000)and significant negative correlations with annual mean air temperature(r=-0.883,-0.869,n=10,p=0.001),which indicated that climate factors controlled SOC and TN distribution pattern along the altitudinal belt.Moreover,the ratio of carbon to nitrogen ranged from 7.8 to 24.7,indicated a easer nutrients release to soil during the process of organic matter decomposition.Additionally,as the main forest component of Qilan Mountains,Picea crassifolia forests showed a mean soil carbon density of 18.13 kg/m~2,which is similar to evergreen conifer forests,but much lower than spruce and fir families.更多还原