不同调酸处理对土壤细菌群落结构及雪茄烟株青枯病发生的影响

Effects of different acid-conditioning treatments on soil bacterial community structure and bacterial wilt incidence of cigar tobacco plants

为探索改善连作烟田土壤酸化现象的最佳措施,降低烟草青枯病发病率,选择常年种植雪茄烟、土壤酸化现象严重且青枯病频发的烟田为试验地,分析增施石灰、油菜还田及增施石灰+油菜还田3种调酸处理对土壤化学性状、细菌群落结构及雪茄烟株青枯病发生的影响。研究结果表明,增施石灰处理能显著提升土壤pH,改善土壤酸化现象,而油菜还田处理可显著增加土壤速效钾含量。相比对照,增施石灰处理土壤的碱解氮、速效钾、有机质含量分别增加17.04%、17.65%、21.74%,油菜还田处理分别增加1.42%、27.38%、23.73%,增施石灰+油菜还田处理分别增加26.79%、47.66%、49.10%。16S rDNA扩增子测序结果表明,对酸化植烟土壤增施石灰能显著增加细菌群落的整体相对丰度。其中,有益菌属芽单胞菌属(Gemmatimonas)的相对丰度相比对照提高124.84%。此外,增施石灰+油菜还田处理能显著提高可降解环境有害物质的细菌—鞘氨醇单胞菌属(Sphingomonas)的相对丰度,降低致病菌青枯雷尔氏菌属(Ralstonia)的相对丰度。移栽后90 d时增施石灰、油菜还田及增施石灰+油菜还田处理相比对照青枯病发病率分别降低37.11%、15.45%、46.01%。

In order to investigate the best measures to improve soil acidification in continuous tobacco fields and reduce the incidence rate of tobacco bacterial wilt,cigar tobacco fields with severe soil acidification and frequent bacterial wilt were selected as the experimental sites.Effects of three acid-conditioning treatments,namely lime application,rape return-to-field,and the combination of lime application and rape return-to-field,were evaluated on the chemical properties of the soil,the structure of the bacterial community,and the bacterial wilt incidence of cigar tobacco plants.The results showed that lime application could significantly increase soil pH and improve soil acidification,while rape returning could significantly increase the amount of available potassium in the soil.Compared to the control,the contents of alkali-hydrolyzable nitrogen,available potassium and organic matter in the soil increased by 17.04%,17.65%and 21.74%after the application of lime,increased by 1.42%,27.38%and 23.73%after rape returning,and increased by 26.79%,47.66%and 49.10%with the combination of the two measures,respectively.The results of 16S rDNA amplification sequence showed that lime application significantly increased the overall relative abundance of bacteria.Compared to the control,lime application increased the relative abundance of the beneficial bacterium Gemmatimonas by 124.84%.In addition,the combination of the two acid-conditioning measures significantly increased the relative abundance of Sphingomonas,which could degrade environmental harmful substances,and decreased the relative abundance of the harmful bacteria Ralstonia.Compared to the control,applying lime,returning rape and the combination of the two measures on day 90 after transplanting reduced the incidence rate of bacterial wilt by 37.11%,15.45%,and 46.01%,respectively.