川东低山丘陵区农业旅游活动对土壤微生物群落结构的影响

Effects of Agricultural Tourism on Soil Microbial Community Structure in Hilly Area of East Sichuan

开展农业旅游对土壤生态环境影响的专题研究,可为休闲农业旅游区的合理开发和有效保护提供理论基础,为评估未来农业旅游活动对土壤生态的影响提供科学依据。本研究以重庆市铜梁区黄桷门奇彩梦园和北碚区金果园游步道两侧的土壤样区为研究对象,通过现场调查、采样以及磷脂脂肪酸谱图分析(PLFAs),系统研究并比较了土壤微生物受影响的距离、主要微生物群落组成及其受冲击程度。结果显示:微生物群落结构受冲击范围在4 m以内(P<0.05),微生物生物量在土壤中的分布随着离游径的距离变小有明显下降趋势;在受农业旅游冲击的范围内细菌,革兰氏阳性细菌,革兰氏阴性菌,真菌的生物量随着离游径的距离变小有明显下降趋势,放线菌在部分样区表现出该规律,原生动物无此规律;对所测PLFAs数据进行多样性和冲击指数分析后得出假单胞菌(16∶0),好氧细菌G+(19∶0 cyclo w8c,15∶0 iso)等受影响程度较大,节杆菌(17∶0),真菌(18∶3 w6c(6,9,12))等受影响程度较小,受冲击程度大小与该微生物在生物总量中所占的比重呈正相关。综上,通过对两园区微生物群落进行评价分析发现调查样区土壤生态系统的稳定性已受到冲击。

The study on the impact of agricultural tourism on soil ecological environment can provide a theoretical basis for assessing the impact of agri-tourism activities on soil environment in future. For this study, soil samples were collected from both sides of tour trail in Qicaimengyuan, Huangjiaomen, Tongliang District and in Jin＇guoyuan, Beibei District. By using field investigation, sampling and phospholipid fatty acid （PLFAs） spectrum graph analysis method, the main microbial community composition, impact range and degree by soil microorganism were investigated systematically in this study. The results showed that impact range on microbial community structure was within 4 m （P 〈 0.05）, while soil microbial biomass clearly declined with the decrease in distance from the tour trail. Within the impact scope by agricultural tourism, the clear downward trends of the biomass were found in bacteria, Gram-positive bacteria, Gram-negative bacteria and fungal with the shortening distance from the trails. Also the above trends happened in some actinomycetes, but not in protozoa. Analysis of diversity and impact index for PLFAs data indicated that Pseudomonas （16 ： 0） and Burkholderia bacteria （19 ： 0 cyclo w8c, 15 ： 0 iso） was more affected, whereas fungi [18 ： 3 w6c （6,9,12）] and arthrobacter （17 ： 0） was less affected. And the impact degree was closely related to the percentage of the microorganism in total biomass. Through the analysis of soil microbial community in the two agricultural parks, soil ecological stability had been affected in sampled region.