State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China.
Sci Total Environ. 2023 Jun 1;875:162663. doi: 10.1016/j.scitotenv.2023.162663. Epub 2023 Mar 7.
Diazotrophs are potential bacterial biofertilizers with efficacy for plant nutrition, which convert atmospheric N into plant available nitrogen. Although they are known to respond strongly to fertilization, little is known about the temporal dynamics of diazotrophic communities throughout plant developmental under different fertilization regimes. In this study, we investigated diazotrophic communities in the wheat rhizosphere at four developmental stages under three long-term fertilization regimes: no fertilizer (Control), chemical NPK fertilizer only (NPK), and NPK fertilizer plus cow manure (NPKM). Fertilization regime had greater effect (explained of 54.9 %) on diazotrophic community structure than developmental stage (explained of 4.8 %). NPK fertilization decreased the diazotrophic diversity and abundance to one-third of the Control, although this was largely recovered by the addition of manure. Meanwhile, Control treatment resulted in significant variation in diazotrophic abundance, diversity, and community structure (P = 0.001) depending on the developmental stage, while the NPK fertilization resulted in the loss of temporal dynamics of the diazotrophic community (P = 0.330), which could be largely recovered by the addition of manure (P = 0.011). Keystone species identified in this study were quite different among the four developmental stages under Control and NPKM treatment but were similar among stages under NPK treatment. These findings suggest that long-term chemical fertilization not only reduces diazotrophic diversity and abundance, but also results in a loss of temporal dynamics of rhizosphere diazotrophic communities.
固氮菌是具有植物营养功效的潜在细菌生物肥料，可将大气氮转化为植物可用氮。尽管已知它们对施肥有强烈的响应，但在不同施肥制度下，固氮菌群落在植物发育过程中的时间动态知之甚少。在这项研究中，我们调查了在三种长期施肥制度下（无肥对照（Control）、仅施用化学 NPK 肥（NPK）和 NPK 肥加牛粪（NPKM））的四个发育阶段小麦根际中的固氮菌群落。施肥制度对固氮菌群落结构的影响大于发育阶段（解释了 54.9%）。尽管添加了有机肥，但 NPK 施肥使固氮菌的多样性和丰度减少到对照的三分之一。同时，对照处理导致固氮菌丰度、多样性和群落结构的显著变化（P = 0.001），这取决于发育阶段，而 NPK 施肥导致固氮菌群落的时间动态丧失（P = 0.330），这可以通过添加有机肥来很大程度上恢复（P = 0.011）。本研究在对照和 NPKM 处理的四个发育阶段中确定的关键种非常不同，但在 NPK 处理的各阶段中相似。这些发现表明，长期施用化学肥料不仅降低了固氮菌的多样性和丰度，而且导致根际固氮菌群落的时间动态丧失。
