Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
School of Environmental and Material Engineering, Yantai University, 30 Qingquan Road, Yantai 264005, China.
Environ Int. 2020 Jul;140:105766. doi: 10.1016/j.envint.2020.105766. Epub 2020 May 1.
Soil microbial communities play a central role in driving multiple ecosystem functions and ecological processes that are key to maintaining the plant productivity. However, we lack sound evidence for the linkage between soil microbial diversity and plant productivity, which hinders our ability to predict the consequences of microbial diversity loss for food security under the context of global environmental change. Here, we used the dilution-to-extinction approach to test the consequences of soil microbial diversity loss for the aboveground plant biomass in a glasshouse experiment. Compared with original soils, the bacterial alpha-diversity (Observed operational taxonomic units and Shannon index) significantly decreased in treatments with serially diluted inoculum. Principal coordinates analysis showed that the overall bacterial community compositions (beta-diversity) in original soils were clearly separated from the treatments with serially diluted inoculum. The aboveground biomass of lettuce harvested from the original soils was significantly higher than that from the sterilized soils regardless of the inoculation. The ordinary least squares regression model showed a significant linear relationship between the plant biomass and bacterial alpha-diversity, indicating that reduction in soil microbial diversity could result in a significant decline in the biomass of lettuce. No significant correlation was observed between plant biomass and soil processes including soil basal respiration and denitrification rates. Structural equation models suggested that the effects of soil microbial diversity on the plant biomass were maintained even when simultaneously accounting for other drivers (soil properties and biological processes). Our study provides experimental evidence that soil microbial diversity is important to the maintenance of the plant productivity and suggests that the functional redundancy in soil microbial communities may be overestimated especially in the agroecological system.
土壤微生物群落在驱动多种生态系统功能和生态过程中发挥着核心作用，这些功能和过程对维持植物生产力至关重要。然而，我们缺乏土壤微生物多样性与植物生产力之间联系的有力证据，这限制了我们预测在全球环境变化背景下微生物多样性丧失对粮食安全的影响的能力。在这里，我们使用稀释至灭绝的方法来检验土壤微生物多样性丧失对温室实验中地上植物生物量的影响。与原始土壤相比，细菌α多样性（观察到的操作分类单元和香农指数）在连续稀释接种物处理中显著降低。主坐标分析表明，原始土壤中的细菌群落组成（β多样性）明显与连续稀释接种物处理区分开来。从原始土壤中收获的生菜地上生物量明显高于灭菌土壤中的生物量，无论接种与否。普通最小二乘回归模型显示，植物生物量与细菌α多样性之间存在显著的线性关系，表明土壤微生物多样性的减少可能导致生菜生物量的显著下降。在植物生物量和土壤过程（包括土壤基础呼吸和反硝化速率）之间没有观察到显著的相关性。结构方程模型表明，即使同时考虑到其他驱动因素（土壤特性和生物过程），土壤微生物多样性对植物生物量的影响仍然存在。我们的研究提供了实验证据，表明土壤微生物多样性对植物生产力的维持很重要，并表明土壤微生物群落的功能冗余可能被高估，尤其是在农业生态系统中。
