贺兰山西坡不同海拔梯度上土壤氮素矿化作用的研究  

Study of Soil Nitrogen Mineralization at Different Altitudes on Western Slopes of Helan Mountains,China

作　　者：王斌[1] 陈亚明[2] 周志宇[1] 

机构地区：[1]兰州大学草地农业科技学院,甘肃兰州730020 [2]兰州大学生命科学学院,甘肃兰州730000

出　　处：《中国沙漠》2007年第3期483-490,共8页Journal of Desert Research

基　　金：国家自然科学基金西部环境研究资助项目计划(90102011);中国科学院寒区旱区环境与工程研究所创新工程资助项目(210097)

摘　　要：采用封顶埋管法对贺兰山西坡不同海拔梯度上土壤铵态氮（NH4＋N）和硝态氮（NO3-N）以及N净矿化速率进行了研究。结果表明：①在海拔1 370-2 940 m的范围内,土壤铵态氮和硝态氮含量随海拔高度的降低而降低。②土壤N净矿化速率随海拔高度的降低呈现出明显的“V”字型变化规律,在海拔2 940 m处最高（平均为0.272 mg.kg^-1.d^-1）,在海拔2 100 m处最低（平均为0.001 mg.kg^-1.d^-1）,之后又随海拔高度的降低而上升,在海拔1 370 m处达到0.136 mg.kg^-1.d^-1的水平。③回归分析显示,土壤矿化氮含量（NH4＋N＋NO3-N）与土壤含水量、全氮、有机质、群落中植物密度、地上生物量呈极显著正相关,与土壤容重、pH值呈极显著负相关。但土壤N净矿化速率与土壤含水量、全氮、有机质、容重、pH值之间却没有相关性。The Close-Top Incubation method was applied to study the variation of NH4＋^-N, NO3^-N and net N mineralization at different altitudes on the western slopes of the Helan mountains. The results are summarized as follows： （1）The mean values of soil NH4＋^-N and NO3^--N decreased with elevation decreasing at the altitudes of between 1 370 m and 2 940 m.（2）Net N mineralization rate decreased rapidly first and then increased with elevation decreasing, it took on ＂V＂ shapes from elevation 1 370 m to 2 940 m. Net N mineralization rate was the highest （0. 272 mg. kg^-1·d^-1 ） at 2 940 m and the lowest（0. 001 mg. kg^-1. d^-1） at 2 100 m, it increased with decreasing elevation below 2 100 m and reached 0. 136 mg.kg^-1.d^-1 at 1 370 m. （3）Regression analysis indicated that soil mineral nitrogen content had a closely positive relationship with soil water content, soil organic matter, soil total nitrogen, soil density, plant population density, plant aboveground biomass, and a closely negative relationship with soil density and soil pH; however, the net N mineralization rate had no correlation with soil water content, soil organic matter, soil total nitrogen, soil density, and soil pH.

关 键 词：封顶埋管法 铵态氮 硝态氮 N净矿化速率 贺兰山 

分 类 号：S153.61[农业科学—土壤学]