[目的]针对目前土壤可溶性氮的提取方法在提取剂种类、水土比及土样保存状态(新鲜和风干)等方面的不同,分析普通山地红壤可溶性氮不同条件下的提取效率,以期为土壤可溶性氮提取提供试验依据。[方法]利用常绿阔叶林植被下普通山地红壤,分别以其新鲜土和风干土为试验材料,探讨2mol/LKCl和0.5mol/LK2SO42种提取剂在水土比4:1、6:1和10:1下提取土壤可溶性氮的差异,研究该类型土壤可溶性氮不同提取条件下的提取效率。[结果]KCl比K2SO4更适合用于提取土壤NH4+-N,KCl提取的NH4+-N不仅量大且稳定性好,K2SO4则需在较大水土比下才能充分提取土壤NH4+-N;2种提取剂在NO3--N提取上的差异性很小,但低水土比下KCl提取NO3--N的稳定性高于K2SO4;两者提取的NO2--N性能非常接近;在土壤SON的提取中,2种提取剂的差异较小,KCl提取的SON量少于K2SO4,但稳定性高于K2SO4,二者的SON提取量具有极显著相关性;用K2SO4提取MBN时可以不考虑水土比的影响,但使用KCl则必须慎重选择水土比。提取新鲜样时KCl和K2SO4之间的差异大于提取风干样时的差异,所以在对新鲜样中可溶性氮提取时应更注重提取剂的选择。[结论]该试验结果为提高土壤可溶性氮的提取效率,增加测定结果的可比性奠定了试验基础。 [Objective] The purpose of this study was to analyze the extraction efficiency of soluble nitrogen in common mountain red soils at different extraction conditions, such as the type of extractant, ratio of soil to water and soil sample (fresh and air dried) Nitrogen extraction provides the experimental basis. [Method] The red soil of common mountainous area under the evergreen broad-leaved forest was used to study the effects of 2mol / L KCl and 0.5mol / L K2SO42 extractants on the ratio of water to soil 4: 1, 6: 1 and dry soil The difference of soil soluble nitrogen was extracted under 10: 1, and the extraction efficiency under different extraction conditions of soil soluble nitrogen was studied. [Result] KCl was more suitable than K2SO4 for extracting NH4 + -N from soil, NH4 + -N extracted from KCl was not only large in quantity and good in stability, but K2SO4 needed sufficient extraction of soil NH4 + -N at large ratio of soil to water. The difference of NO3 - N extraction was small, but the stability of NO3 - N extracted by KCl was higher than that of K2SO4 at low ratio of water to soil. The NO2 - N extracted by the two methods was very close to each other. , The difference of the two extractants is smaller, the amount of SON extracted by KCl is less than that of K2SO4, but the stability is higher than that of K2SO4. The extraction of SON has a very significant correlation. The extraction of MBN with K2SO4 can not consider the effects of water and soil ratio , But KCl must be carefully selected water and soil ratio. The difference between KCl and K2SO4 when extracting fresh samples is greater than that when extracting dried samples, so the extraction solvent should be more focused on the extraction of soluble nitrogen in fresh samples. [Conclusion] The results of this experiment laid the experimental foundation for improving the extraction efficiency of soil soluble nitrogen and increasing the comparability of determination results.