Abstract: Due to soil microbial community structure and diversity and their change to a certain extent reflect the quality of the soil,the saline soil microbial diversity and population structure have certain application value for saline soil improvement. Saline soil is a special kind of soil type,may be a lot of salt resistance,alkali resistance and halophilic extremophiles groups,and has great development and utilization value,can build saline soil microbial macro gene pool,and screen out useful genetic resources used by mankind. To establish a method of total DNA extraction for investigation of the microbial population structure and diversity at saline-alkali soil in Hexi corridor,four kinds of methods that are M1(Omega kit method ),M2(MoBio kit method ),M3(modified high-salt method) and M4(Calcium chloride-SDS-Enzymatic) were used. The results showed that: 23.1 kb DNA fragments were obtained by the methods,and no DNA degradation. But the DNA extraction results were very different between the 4 methods,M1 and M2 shows no clear bands but high pure DNA; M3 and M4 obtain higher DNA amount than M1 and M2,however,the DNA obtained by M3 has more impurities which affects the accuracy of subsequently analysis. The DNA purity by M4 are more approximate to the kit method,the amount of DNA extraction reached 452.875 μg·g^-1,much higher than the other 3 kinds of methods,more suitable for the subsequent experiments. The results indicated that M4 is suitable for total DNA extraction to study microbial abundance and diversity from saline-alkali soil in Hexi Corridor.

Key words: saline-alkali soil, microorganism, total DNA extraction method, Hexi Corridor