有机物料深混还田对白浆土微生物群落特征的影响

Effects of deep incorporation of organic materials on microbial community characteristics in albic soil

  • 摘要: 为探究有机物料深混还田对白浆土耕层和亚耕层微生物群落特征的影响,本研究基于白浆土为期两年的田间定位试验,设置深翻35 cm(DT,无有机物料)、深翻35 cm+秸秆(DTS)、深翻35 cm+有机肥(DTM)、深翻35 cm+秸秆+有机肥(DTSM),以农民常规浅翻15 cm(CT,无有机物料)为对照,开展秸秆和有机肥对白浆土微生物群落特征影响的研究。结果表明:与CT处理相比,DTM和DTSM处理显著增加了耕层土壤速效钾(AK)含量和pH值,DTSM处理显著增加了土壤碱解氮(AN)含量(P<0.05)。在亚耕层,DT、DTS、DTM和DTSM处理下土壤有机碳(SOC)、全氮(TN)、AN和AK含量较CT处理显著增加(P<0.05)。有机物料深混还田对耕层和亚耕层土壤微生物群落特征有影响,变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)和酸杆菌门(Acidobacteriota)构成主要细菌类群,真菌群落则以子囊菌门(Ascomycota)和被孢霉门(Mortierellomycota)为优势种群。DTSM处理显著提升耕层的Chao1和Shannon指数,以及亚耕层的Shannon指数(P<0.05)。主坐标分析(PCoA)表明,土壤细菌和真菌群落结构在不同处理间存在差异,其中DTSM和DTM显著改变了细菌的群落结构,并与CT和DT处理明显分离,而CT和DT处理的细菌和真菌群落相似性相对较高。冗余分析表明,耕层土壤微生物群落特征变化主要与AN、AK和pH值呈显著正相关关系(P<0.05),而亚耕层主要与SOC和TN呈显著正相关关系(P<0.05)。随机森林模型分析表明,pH值和AK分别是影响细菌和真菌群落的关键因子,贡献度分别为0.25和0.28。有机肥或秸秆配施有机肥是提高白浆土养分含量和微生物群落特征的最佳策略。

     

    Abstract: In order to investigate the effects of deep incorporation of organic materials on microbial community characteristics in the plow layer and subsoil of albic soil, a two-year field experiment was conducted. The experiment included the following treatments: deep tillage at 35 cm (DT, no organic material), deep tillage at 35 cm plus straw (DTS), deep tillage at 35 cm plus manure (DTM), deep tillage at 35 cm plus straw and manure (DTSM), with conventional shallow tillage at 15 cm (CT, no organic materials) as the control. The results show that compared to the CT treatment, DTM and DTSM significantly increase the content of AK (available potassium) and pH in the plow layer, while DTSM significantly increases the content of AN (available nitrogen) (P<0.05). In the subsoil, the contents of SOC (soil organic carbon), TN (total nitrogen), AN, and AK are significantly higher in the DT, DTS, DTM, and DTSM treatments compared to CT (P<0.05). Deep incorporation of organic materials significantly influences soil microbial community characteristics in both the plow layer and subsoil. The dominant bacterial phyla are Proteobacteria, Actinobacteriota, and Acidobacteriota, while the fungal communities are primarily dominated by Ascomycota and Mortierellomycota. DTSM treatment significantly increases the Chao1 and Shannon indices in the plow layer and the Shannon index in the subsoil (P<0.05). Principal coordinate analysis (PCoA) indicates differential effects of the treatments on soil microbial communities. A pronounced shift in bacterial community characteristics is observed in DTSM and DTM treatments, which clearly separate from the clusters of the CT and DT treatments. In contrast, CT and DT treatments maintain highly similar bacterial and fungi community profiles. Redundancy analysis indicates that changes in microbial community in the plow layer are significantly positively correlated with AN, AK, and pH (P<0.05), while in the subsoil, they are significantly positively correlated with SOC and TN (P<0.05). Random forest model analysis showed that pH value and available potassium (AK) were the key factors affecting bacterial and fungal communities, with contribution degrees of 0.25 and 0.28, respectively. In conclusion, the application of organic fertilizer alone or combined with straw (DTSM/DTM) represents the optimal strategy for enhancing nutrient content and microbial community characteristics in albic soil.

     

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