中文摘要：

[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／LK2SO4 2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K2SO。更适合用于提取土壤NHd—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NO卜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。

英文摘要：

[Objective] The extraction efficiency of soluble nitrogen in common moun- tain red soil under different conditions was analyzed to provide experimental refer- ences for the extraction of soil soluble nitrogen. [Method] The fresh soil and air-dried soil, which were the common mountain red soil under evergreen broad-leaved forest vegetation, were used as the experimental materials. The 2 mol/L KCI and 0.5 mol/L K2SO4 were used as the extractants to extract the soil soluble nitrogen with the extractant-to-soil volume ratio at 4：1, 6：1 and 10：1, respectively, to examine the extrac- tion efficiency of soluble nitrogen in the experimental soil with different extraction conditions. [Result] Compared with K2SO4, the NH4＋-N extracted by KCI was better in quantity and stability; while only at high extractant-to-soil volume ratio could K2SO4 fully extract the soil NH4＋-N. The 2 extractants showed small difference in extracting NO3--N, but at low extractant-to-soil volume ratio, the stability of NO3--N extracted by KCI was higher than that extracted by K2SO4. The properties of NO2- -N extracted by the 2 extractants were very similar. As for soil SON extraction, there was small dif- ference between the 2 extractants. However, the SON extracted by KCI was fewer in quantity than that by K2SO4, but had higher stability, and the extracted SON amount of the 2 extractants showed significant correlation. The extractant-to-soil ratio had little effect on MBN extraction using K2SO4, but the effect was significant when using KCI to extract MBN. The difference between the extraction efficiency of KCI and K~SO4 in extracting fresh soils was greater than that in extracting air-dried soil; therefore, the extractants should be carefully selected in soluble nitrogen extraction from fresh soil. [Conclusion] The results lay the experimental foundation for improving the extraction efficiency of soil soluble nitrogen and increasing the comparability of measurement results.