• ISSN 1008-505X
  • CN 11-3996/S
王西亚, 吕继龙, 何萍, 范分良, 仇少君, 徐新朋, 赵士诚. 玉米秸秆分解过程中细菌群落组成演化特征[J]. 植物营养与肥料学报, 2021, 27(1): 45-53. DOI: 10.11674/zwyf.20242
引用本文: 王西亚, 吕继龙, 何萍, 范分良, 仇少君, 徐新朋, 赵士诚. 玉米秸秆分解过程中细菌群落组成演化特征[J]. 植物营养与肥料学报, 2021, 27(1): 45-53. DOI: 10.11674/zwyf.20242
WANG Xi-ya, Lü Ji-long, HE Ping, FAN Fen-liang, QIU Shao-jun, XU Xin-peng, ZHAO Shi-cheng. Succession in bacterial community during maize straw decomposition[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(1): 45-53. DOI: 10.11674/zwyf.20242
Citation: WANG Xi-ya, Lü Ji-long, HE Ping, FAN Fen-liang, QIU Shao-jun, XU Xin-peng, ZHAO Shi-cheng. Succession in bacterial community during maize straw decomposition[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(1): 45-53. DOI: 10.11674/zwyf.20242

玉米秸秆分解过程中细菌群落组成演化特征

Succession in bacterial community during maize straw decomposition

  • 摘要:
    目的  土壤中存在着大量的分解秸秆的微生物。研究秸秆分解过程中细菌群落组成的演化规律,对了解和调控农田微生物群体组成以促进秸秆分解具有重要意义。
    方法  试验于2014年10月至2015年10月在河南省农业科学院原阳试验基地进行,将成熟期玉米秸秆 (茎和叶) 烘干,剪成长1~2 cm 、 宽0.3~1 cm的碎片,称12 g样品 (相当于8 t/hm2) 装入15 cm × 10 cm的尼龙网包 (孔径0.04 mm) 内,于10月5日冬小麦出苗后埋置在小麦垄间。分别于埋置后0、1、2、4、7、10和12个月收集秸秆包和土壤样品。测定秸秆样品干物质量和碳氮含量,选择埋置了0、2、4、7和12个月的秸秆及其土壤样品分析细菌丰度及群落组成。
    结果  秸秆埋入土壤后的前2个月内分解最快,然后逐步减慢,在1、2、4、7、10和12个月后分别降解了总生物量的19.2%、32.9%、44.2%、52.2%、66.8%和73.8%。秸秆埋入土壤后,秸秆和土壤中细菌丰度均显著增加,分别于第4和7个月达到最高后开始下降。秸秆细菌的丰度指标OTUs、ACE、Chao1和多样性指标Shannon随试验时间的延长逐步增加,而Simpson指数随试验时间延长逐步降低,而土壤中这些指标在试验过程中没有显著变化。与刚埋置秸秆时相比,埋置2个月后的秸秆细菌Bacteroidetes门相对丰度明显增加,主导细菌群为Bacteroidetes和Proteobacteria门。Actinobacteria丰度在埋置2个月后明显降低,然后又随试验时间延长逐步增加。Planctomycetes、Saccharibacteria、Verrucomicrobia、Acidobacteria、Chloroflexi和Gemmatimonadetes丰度在原始秸秆中较低,埋入土壤后随试验时间延长逐步增加。Sphingobacteriia、Gammaproteobacteria、Alphaproteobacteria和Flavobacteriia主导前期细菌纲组成,而Actinobacteria、Anaerolineae和Bacilli纲丰度在后期逐步增加。秸秆分解速率主要受其碳含量影响,秸秆细菌群落组成前期与秸秆碳含量相关,后期与秸秆氮含量相关。随着试验的进展,秸秆细菌群落组成与土壤中的细菌群落组成趋同。
    结论  秸秆埋入土壤后前2个月的分解速率最高,随后逐步降低。秸秆分解前期细菌群落由富营养型组分Bacteroidetes和Proteobacteria门和Sphingobacteriia、Gammaproteobacteria、Flavobacteriia和Alphaproteobacteria纲主导,随后被逐步增加的贫营养型组分Actinobacteria、Acidobacteria、Chloroflexi、Saccharibacteria门和Deltaproteobacteria、Actinobacteria纲等代替。秸秆碳氮含量变化是影响秸秆分解及其过程中细菌群落演化的主要原因。

     

    Abstract:
    Objectives  Many microbial communities exist in soils and play dominant roles during straw decomposition process. Understanding the succession pattern in bacterial community during crop straw decomposition is imperative in regulating and improving straw decomposition.
    Methods  The research was conducted at the Yuanyang Experimental Station of Henan Academy of Agricultural Sciences from October 2014 to October 2015. Dry maize straws (stalks and leaves) were shredded into 1‒2 cm long and 0.3‒1 cm wide, and 12 g of the straw samples were loaded into non-biodegradable nylon mesh bags (15 cm × 10 cm with pore diameter of 0.04 mm), and then buried 12 cm deep in the middle of two rows of winter wheat in October 5, 2014. Straw bags and soil samples were retrieved at 0, 1, 2, 4, 7, 10 and 12 months after burial for the determination of dry matter mass, C/N ratio of straw samples, and the bacterial abundance and diversity in straw and soil samples.
    Results  The rate of straw decomposition was greatest in the first two months after burial in soil, and there after decreased gradually. Reduction in straw masses was 19.2%, 32.9%, 44.2%, 52.2%, 66.8% and 73.8% of the total mass at 1, 2, 4, 7, 10 and 12 months after burial, respectively. The bacterial abundance in residual straw and soil increased significantly after burial, attaining its peak at 4 and 7 months, respectively. The bacteria richness index OTUs, ACE, Chao1 and Shannon in residual straws increased gradually with the extension of the experimental duration, while Simpson index gradually decreased. However, these indexes in soils did not change significantly during the study period. Compared with the initial sampling period (0 month), the relative abundance of phylum Bacteroidetes in straws increased significantly after 2 months. The bacterial communities dominated were Bacteroidetes and Proteobacteria at the early stage, afterwards, their abundances gradually decreased. The abundance of Proteobacteria remained high across the decomposition process while that of Actinobacteria was significantly low at 2 months but gradually increased; the abundances of Chloroflexi, Saccharibacteria, Acidobacteria, Verrucomicrobia, Planctomycetes and Gemmatimonadetes were low initially but also increased with time. Bacterial class composition was dominated by Sphingobacteriia, Flavobacteriia, Gammaproteobacteria and Alphaproteobacteria in the early stage, and the abundance of Actinobacteria, Anaerolineae and Bacilli gradually increased at the later stage. The rate of straw decomposition was mainly affected by its carbon content. Straw bacterial community was correlated with straw carbon and straw nitrogen in the early and later stages of decomposition, respectively. The bacterial community composition in straw tended to be similar to those in soils.
    Conclusions  Decomposition of maize straw is fast during the first 2 months of burial but gradually decreases afterwards. The dominating bacterial communities during the early stage are phylum Bacteroidetes and Proteobacteria, and class Sphingobacteriia, Gammaproteobacteria, Flavobacteriia and Alphaproteobacteria. However, they are succeeded by phylum Actinobacteria, Saccharibacteria, Acidobacteria, Chloroflexi, and class Deltaproteobacteria and Actinobacteria at the later stage of decomposition. The change in the carbon and nitrogen contents of straw is found to be mainly responsible for straw decomposition and the succession in bacterial community structure during straw decomposition process.

     

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