干旱半干旱地区砂田交界层土壤微生物区系研究

Study on soil micro flora in boundary soil layer of gravel and sand mulched field in arid and semiarid area of China

为探讨干旱半干旱地区砂田土壤微生物特征,对不同砂龄砂田交界层土壤微生物区系及其影响因素进行试验研究。结果表明:在交界层土壤中的微生物区系以细菌为主,放线菌次之,真菌最少;砂田交界层土壤微生物数量与砂田砂龄有关,砂龄为13 a的土壤细菌数量达最高,砂龄为26 a砂田,土壤真菌数量达最高,放线菌的数量和比例都达到最大;随着砂田的老化程度加深,细菌数量减少,真菌和放线菌的数量增加,土壤微生物数量可以作为监测砂田老化程度的指标之一。碳源是限制微生物生长的主要因素之一;在较小的pH值变动范围内,pH值对细菌、真菌和放线菌的数量无显著影响,土壤呼吸强度与细菌数量有关;土壤水分是限制微生物生长的主要因素。

To study the soil microbial characters in gravel and sand mulched field（GSMF） in arid and semiarid area,the soil micro flora and the influence factors of GSMF and its boundary layer in different age of GSMF had been studied through experimentation.The results showed that the quantity of micro flora in boundary layer was bacteriaactinomycetefungi.It is related on soil microbial number and the age of GSMF,that is the number of bacteria reached the highest number when the age of GSMF was 13 a.When the age of GSMF was 26 a,the number of fungi and actinomycete reached the highest number,and the percentage of actinomycete reached the highest rate of total microbial number too.That was with the aging degree adding of the GSMF,the number of bacteria decreased,and the number of fungi and actinomycete increased.So the number of microbial can be the target that forecast the aging degree of the GSMF.C source was one of the main factors that restrict microbial development.It was no significant influence to bacteria,fungi and actinomycete by pH value when it in lesser alteration.The soil respiration intensity was related to bacteria quantity.Soil moisture content is the main factor which restricts bacteria development.