有机和常规苹果园的土壤微生物结构差异研究

Comparison of soil microbe community structure between organic and conventional apple orchards

【目的】研究有机苹果园和常规苹果园的土壤微生物结构差异,为苹果园土壤改良提供理论依据。【方法】以北京市昌平区连续5 a应用有机栽培方法的10个苹果园和4个常规管理苹果园的土壤为对象,利用磷脂脂肪酸多态性(PLFA)技术和稀释平板计数法研究两种管理方式下果园土壤微生物的结构差异。【结果】结果表明,有机园和常规园的土壤微生物群落结构差异显著。常规果园土壤微生物总PLFA为114.99 nmol·g-1,是有机果园(43.44 nmol·g-1)的2.6倍,但有机果园PLFA丰富度高19%,生物多样性高。有机苹果园土壤微生物中革兰氏阳性菌与革兰氏阴性菌的比例为1.50,常规苹果园为0.30;有机苹果园真菌生物量占2.84%,常规果园为6.55%,差异显著。二类果园可培养微生物数量差异不显著。【结论】有机苹果园和常规苹果园的土壤微生物结构存在显著差异,常规苹果园农药及化肥的使用降低了微生物群落的丰富度和功能多样性。

[Objective]The difference of soil microbe community structure between organic apple orchards and conventional apple orchards was studied. [Method]Soil microbe community structure of 10 organic apple orchards and 4 conventional apple orchards in Beijing was studied employing PLFA method for the whole microbe community and serial dilution-plate counting method for cultivable microbe. [Result]The difference of soil microbe community structure was significant. Total PLFA of organic apple orchards mi- crobe was 43.44 nmol-g-l, which was 62% lower than that of conventional orchards （114.99 nmol. g-l）, on the contrary, the richness index of PLFA in organic orchards was 19% higher, indicating that organic or- chards maintained more complex microbe community. Ratio of Gram-positive bacteria to Gram-negative bacteria was 1.5 in organic orchards, which was 5 folds compared to conventional orchards （0.3） ; the total fungi PLFA of organic orchards and conventional orchards were 2.84% and 6.55%, respectively. The cul- tivable microbe showed no significant difference, indicating that the main difference resulted form non- cultivable species. [Conclusion]Organic apple orchards and conventional apple orchards showed remark- able difference in soil microbe community, conventional management reduced the richness of microbe, while ratio of Gram-positive bacteria to Gram-negative bacteria and percentage of fungi could be impor- tant index for monitoring orchard soil quality