| 长期施氮对茶园土壤细菌群落结构、功能类群及群落构建的影响 |
| 摘要点击 1450 全文点击 13 投稿时间：2025-07-02 修订日期：2025-10-12 |
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| 中文关键词 长期施氮 细菌群落组成 细菌生态功能 共现性网络 群落构建 |
| 英文关键词 long-term nitrogen application bacterial community structure bacterial ecological functions co-occurrence network community assembly |
| DOI 10.13227/j.hjkx.202507019 |
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| 中文摘要 |
| 氮肥施用是提升茶叶产量和品质的重要因素之一，也是影响土壤细菌群落结构的主要人为因素. 依托于2011年开始的长期田间水泥池定位试验，设置4种施氮水平（不施氮肥，0 kg·hm-2，N0；低量施氮水平，112.5 kg·hm-2，N1；中量施氮水平，225 kg·hm-2，N2；高量施氮水平，450 kg·hm-2，N3；均以N计）. 2020年春茶（5月）和秋茶（10月）期间采集了表层土壤（0~20 cm），利用16S rRNA高通量测序，分析了长期施氮对茶园土壤细菌群落结构、功能多样性及群落构建的影响，并阐明土壤菌群和环境因子的互作关系. 结果表明：① 土壤细菌多样性随施氮量增加呈单峰变化，与N0处理相比，春季采样期N2和N3处理土壤细菌Ace、Chao1和Shannon指数分别显著下降了6.47%~18.74%、5.93%~19.72%和3.99%~6.61%，秋茶采样期N2和N3处理土壤细菌Ace、Chao1和Shannon指数分别显著下降了10.94%~25.95%、11.02%~25.30%和3.61%~8.62%. ②主坐标分析（PCoA）和置换多元方差分析（PERMANOVA）结果表明施氮显著改变了土壤细菌群落结构；与N0处理相比，N2和N3处理显著增加了两个季节厚壁菌门的相对丰度，N3处理均降低了酸杆菌门和黏球菌门的相对丰度，铵态氮、酸性磷酸酶和硝态氮是影响细菌群落差异的最主要因素. ③ FAPROTAX细菌功能分组主要以化能异养（33.01%）、好氧化能异养（32.34%）和纤维素分解（11.76%）等为主，施氮显著改变了土壤细菌生态功能，N2和N3处理显著降低了参与氮素循环中功能类群的相对丰度，铵态氮、有效钾和全氮是解释细菌生态功能差异的最主要因素. ④ 与N0处理相比，N1处理增加了土壤细菌网络结构稳定性，N2和N3处理降低了细菌网络结构稳定性. 在群落演替过程中，随机性过程主导长期施氮下茶园土壤细菌群落构建，高氮处理增强了确定性过程在群落组装中的作用. ⑤相关性分析表明，放线菌门、厚壁菌门和WPS-2与茶叶产量、游离氨基酸含量之间呈显著正相关，与大多数儿茶素组分之间呈显著负相关，可能是影响茶叶品质变化的主要因素之一. 总体而言，长期施氮改变了茶园土壤细菌群落结构和代谢功能，中低氮处理有利于保持茶园土壤细菌多样性和结构稳定性. |
| 英文摘要 |
| Nitrogen fertilizer application is an essential aspect of tea plantation management to improve the yield and quality of tea， and the nitrogen fertilizer constitutes the major artificial factor affecting the soil bacterial community structure. The field experiment （small cement pond） was set up in the base of the Tea Research Institute of Fujian Province （beginning in 2011）， and four nitrogen levels were applied： N0 （0 kg·km-2）， N1 （112.5 kg·hm-2）， N2 （225 kg·hm-2）， and N3 （450 kg·hm-2， all measured by N）， and each treatment was repeated four times. We used 16S rRNA high-throughput sequencing to analyze the effects of long-term nitrogen applications on the soil bacterial diversity， functional groups， and community assembly. Further， the Pearson correlation analysis and redundancy analysis （RDA） were also used to examine the soil property factors that drive the community structure. The results showed that： ① The soil bacterial diversity followed a unimodal trend with increasing N concentration. Compared with that in the N0 treatment， the soil bacterial diversity index （Ace， Chao1， and Shannon） of N2 and N3 treatments significantly decreased by 6.4%-18.74%， 5.93%-19.72%， and 3.99%-6.61% in the spring sampling period， and the soil bacterial diversity index of N2 and N3 treatments significantly decreased by 10.94%-5.95%， 11.02%-25.30%， and 3.61%-8.62% in the autumn sampling period. ② The results of principal coordinates analysis （PCoA） and permutational multivariate analysis of variance （PERMANOVA） showed that long-term nitrogen application drastically changed the community structures of soil bacteria in tea plantations. Compared with N0， N2 and N3 significantly increased the relative abundance of Firmicutes in two seasons， but N3 significantly decreased the relative abundance of Acidobacteria and Myxococcota， and the most important factors affecting the differences in bacterial communities were ammonium nitrogen， acid phosphatase， and nitrate nitrogen. ③ The functional prediction with FAPROTAX showed that chemoheterotrophy （33.01%）， aerobic chemoheterotrophy （32.34%）， and cellulolysis （11.76%） were the main ecological functions in tea garden soils. Long-term nitrogen application significantly changed the ecological functions of bacteria in tea garden soils， and the relative abundances of several functional genes associated with N cycling were reduced by medium-high nitrogen treatments （N2 and N3）. Redundancy analysis （RDA） showed that the ammonium nitrogen， available potassium， and total nitrogen were the most important factors to explain the differences in bacterial ecological functions. ④ Network analysis revealed that the N1 treatment increased the number of edges， average degree， average clustering coefficient， and network density of bacterial networks， and the N2 and N3 treatments significantly decreased the number of edges， average degree， and network density of bacterial networks compared with those in the N0 treatment， indicating that the of soil bacterial networks were reduced by the middle and high nitrogen treatments. In the process of community succession， stochastic processes dominated the construction of the tea garden soil bacterial community under long-term nitrogen application， and the deterministic processes were enhanced in the community assembly under high nitrogen treatments. ⑤ Correlation analysis showed that Actinobacteria， Firmicutes， and WPS-2 were significantly positively correlated with tea yield and free amino acid and significantly negatively correlated with most of the catechin components， which may be one of the main microbial groups affecting the change in tea quality. Overall， long-term nitrogen application changed bacterial community structure and metabolic function of the tea garden soil， and the medium and low nitrogen treatments were beneficial for maintaining the bacterial diversity and structural stability of the tea garden soil. |
