【摘要】 利用祁连山区3个气象站常年监测的冻土与温度资料,研究了0~60 cm层次土壤有机碳和全氮分布及与海拔高度、土壤温度的关系,并在室内模拟研究了冻融过程(-20~15℃)对祁连山青海云杉林和高山灌丛林土壤有机碳和氮矿化过程的影响.结果表明:土壤的有机碳和全氮含量随海拔上升呈增加趋势,土壤有机碳和全氮含量与海拔呈显著正相关关系,与土壤温度呈显著负相关关系.室内模拟实验表明,经过多次冻融循环过程,冻融处理抑制了土壤有机碳矿化过程,对照处理土壤有机碳矿化速率高于冻融处理.冻融次数也是影响土壤有机氮矿化的一个重要因素,经过42次冻融,青海云杉林和高山灌丛林土壤中有机氮质量分数分别提高了2.42倍和2.82倍.土壤冻融过程促进了土壤有机氮的矿化,有利于土壤中有效氮的累积.更多还原

【Abstract】 The vertical distribution patterns of surface soil( 0 ~ 60 cm) organic carbon( SOC) and total nitrogen( TN) from three main monitoring stations in the Qilian Mountains were studied. The results indicate that SOC and TN have significant positive correlation with altitude,and significant negative correlation with soil temperature. The laboratory experiment of freezing and thawing cycles(- 20 ~ 15 ℃) showed that with the circles of freezing-thawing increasing,the carbon mineralization rate was higher than that in soil of Picea crassifolia forest and alpine scrub forest,meanwhile,the inorganic nitrogen concentration was 2. 42 and 2. 82 times as that of the control treatment after reciprocal incubation. Thus,soil freezing and thawing process is benefited to the accumulation of soil inorganic nitrogen content.更多还原