为了寻求一种快速、简便、经济且高效的旱地土壤微生物DNA提取方法，在QIN等的稻田土壤DNA提取方法基础上，进行改良试验：（1）称0.3 g干土加入300 μL无菌水，于-80 ℃过夜；（2）研究加入CTAB和SDS的最适配比，CTAB、SDS的总体积为500 μL，并设置加玻璃珠和不加玻璃珠试验，最后将改良方法与试剂盒法进行土壤微生物DNA提取效果对比分析。结果表明，将称取的0.3 g干土中加入300 μL无菌水于-80 ℃过夜，并调整CTAB与SDS的体积配比为100[KG-*4]∶[KG-*4]400，所提取的红壤旱地土微生物DNA含量最高达到6.29 μg/g（略低于试剂盒法的7.46 μg/g），纯度较试剂盒法高，PCR扩增效果良好，此法相对于试剂盒提取法更经济、高效。因此，该改良QIN法适合于红壤旱地土壤微生物DNA的提取。

In order to explore a rapid, simple, economical and efficient DNA extraction method of microorganisms in dryland soil,based on the extraction method of DNA from paddy soil by Qin et al,an improved experiment was carried out:(1)placing 0.3 g dry soil in 300 μL aseptic water for overnight at -80℃ ;(2)determining ratio of CTAB to SDS with the total volume of 500 μL,and exploring the effect of adding glass bead or not,finally the microbial DNA extraction effect of modified method was studied compared with the reagent box method.The results showed that when placing 0.3 g dry soil in 300 μL aseptic water for overnight at -80℃ ,and adjusting the volume ratio of CTAB to SDS to be 100∶400,the highest content of microbial DNA extracted from red soil in dryland by the improved method was 6.29 μg/g,which was lower than the reagent box method(7.46 μg/g),the purity was better than the reagent box method,and the PCR amplification effect was good.Compared with the reagent box method,the improved method was more economical and efficient.Therefore,the modified method was suitable for the extraction of microbial DNA from red soil in dryland.