不同施肥年限对红壤细菌多样性及群落结构演替的影响

为探讨不同年限施肥处理对旱地红壤细菌多样性和群落结构演替的影响,基于中国科学院红壤生态实验站设置的不同秸秆还田方式长期定位试验,采集种植玉米后第1年(Y2011)、第3年(Y2013)和第7年(Y2017)的土样进行分析。试验处理分为不施肥(CK)、化肥(N)和化肥+秸秆猪粪配施(NSM)3个处理,通过高通量测序技术研究旱地红壤细菌多样性和群落结构差异。结果表明:(1)施肥处理显著提高了土壤有机碳、全氮、全磷和有效磷养分含量,NSM处理对土壤肥力的提升效果比N处理好,且随着施肥年限的延长,提升效果越显著;(2)与Y2011相比,Y2013和Y2017下CK、N和NSM处理的细菌α多样性均显著提高,且N和NSM处理细菌多样性显著高于CK处理;(3)主坐标分析和聚类分析表明,土壤细菌群落主要通过施肥年限聚类在一起,但同一施肥年限下不同施肥处理之间细菌群落结构没有显著差异;(4)土壤全磷是驱动细菌多样性和群落结构变异的最关键因子。本研究从细菌多样性增加的角度,为探索有机培肥下红壤肥力提升和生态系统健康管护提供了科学依据。

Effects of Long-term Fertilization on Bacterial Diversity and Community Structure Succession in Red Soil

A long-term field experiment was conducted in corn mono-cropping system at the National Agro-Ecosystem Observation and Research Station in Yingtan to investigate the effects of fertilization treatment and year on bacterial diversity and community structure in an upland red soil, in which the treatments included CK (no fertilizer), N (chemical fertilizer) and NSM (chemical fertilizer with straw and manure). Soil samples were collected in the 1^st year (Y2011), the 3^rd year (Y2013), and the 7^th year (Y2017), and high-throughput sequencing technology was used to determine bacterial diversity and community structure. The results showed that the contents of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available phosphorus (AP) were significantly increased under fertilization treatments. NSM showed a better effect on soil fertility than N, and the effect became more significant with the increase of fertilization history. Bacterial α-diversity was significantly improved in Y2013 and Y2017 compared with Y2011, and was significantly higher under N and NSM than CK. Principal coordinate analysis and cluster analysis based on Bray-Curtis distance consistently showed that bacterial communities were clustered together primarily through the fertilization year. There was no significant difference in bacterial community structure between different fertilization treatments in the same fertilization year. TP was the most critical factor driving variations in the bacterial diversity and community structure. This study provides the scientific proof for the enhancement of red soil fertility and ecosystem health under organic fertilization from the viewpoint of promoting microbial diversity.