【摘要】 以祁连山西段草地土壤氮为研究对象,采用PVC管野外培养法,测定分析土壤氮及其理化指标,计算氮矿化量、矿化速率,分析引起土壤氮矿化的主要环境变量。结果表明:（1）全氮、p H值在海拔上均差异显著（P<0.05）,有机质差异不显著（P>0.05）,NH₄⁺-N在2 700 m、2 800 m、2 850 m、2 900 m、3 000 m、3 050 m差异显著（P<0.05）,其他海拔差异不显著（P>0.05）,NO₃^--N在海拔上差异显著（P<0.05）。（2）野外培养能促进土壤氮矿化,矿化速率在海拔上遵循二次多项式。（3）土壤理化指标对土壤氮矿化速率影响大小依次为:pH值>K>NH₄⁺-N>全氮>水分>温度>容重,土壤氮矿化速率与全氮、K、pH值、NH₄⁺-N、水分之间均有较显著的相关性（P<0.05）,与全氮、K、NH₄⁺-N、水分之间有二次多项式显著相关性,与pH值有显著的线型正相关,容重有对数正相关,土温有幂函数正相关,后两者相关性不强。（4）通过研究发现能促进土壤氮矿化各变量因子的赋值范围为:pH值（7.2⁸.4）、水分（21.8%³3.27%）、土温（4.41⁸.91℃）。更多还原

【Abstract】 In order to explore the characteristics and the main causes of soil nitrogen mineralization in western Qilian Mountains,Gansu Prouince,China,the experiments were conducted in the grassland there utilizing the PVC pipe culture method in the field to measure the soil nitrogen and its associated physical and chemical elements. The nitrogen mineralization amount and the nitrogen mineralization rate were calculated in order to understand the main environmental variables that cause soil nitrogen mineralization. The results showed that,there were significant differences（ P < 0. 05） in total nitrogen and p H value along with the altitude while the difference in organic matter was not significant（ P > 0. 05）. There were obvious differences in NH₄⁺-N at various elevations including 2 700 m,2 800 m,2 850 m,2 900 m,3 000 m,and 3 050 m（ P < 0. 05）,while no significant difference for NO₃^--N along with the altitude（ P < 0. 05）.（ The soil nitrogen mineralization was promoted by field culture） The value of mineralization rate was following a quadratic polynomial in altitude. The impacts of physicochemical elements on the rate of soil nitrogen mineralization appeared in the sequence as follows based on descending order of influencing extent: pH value,K,NH₄⁺-N,total nitrogen,the water content,the temperature and soil bulk density. For the soil nitrogen mineralization rate,there were a significant correlation（ P < 0. 05） with total nitrogen,K,p H value,NH-4-N and water content as a quadratic polynomial correlation,a significant positive linear correlation with the p H value,a logarithm positive correlation with the soil bulk density,and a power function positive correlation with the soil temperature. However the correlation between the soil nitrogen mineralization rate and the latter two was not strong. The study also found that,the value ranges of the variable factors that can promote soil nitrogen mineralization were,pH value from 7. 2 to 8. 4,water content from 21. 8% to 33. 27%,and soil temperature from 4. 41°C to 8. 91°C.更多还原