再植桃园不同改良措施对桃树根际土壤理化性质和细菌多样性的影响

Effects of different improvement measures on physicochemical properties and bacterial diversity of rhizosphere soil in replanted peach orchard

  • 摘要:目的】分析不同改良措施对桃树根际土壤理化性质和细菌多样性的影响,为缓解桃树连作障碍、推动桃种植业可持续发展提供理论依据。【方法】以再植桃树根际土壤为研究对象,设置3个处理:原土深翻后轮作一季水稻+自然生草(DR+NG)、原土深翻后轮作一季水稻+苜蓿生草(DR+PA)和原土深翻+自然生草(DT+NG)。通过测定土壤理化性质及高通量测序,分析不同改良措施下桃园根际土壤细菌群落的组成和多样性,并进行功能预测。【结果】土壤理化性质分析结果显示,与DT+NG处理相比,DR+NG处理可显著提高土壤pH及碱解氮和有机质含量(P<0.05,下同),显著降低电导率和速效钾含量;与DR+NG处理相比,DR+PA处理的土壤pH、电导率以及碱解氮和有机质含量均显著降低,速效钾含量显著提高。细菌群落分析结果显示,与DT+NG处理相比,DR+NG处理的拟杆菌门(Bacteroidota)、泉古菌门(Crenarchaeota)、匿杆菌门(Latescibacterota)、NB1-j和硝化螺旋菌门(Nitrospirota)相对丰度均呈显著或极显著(P<0.01)上升;与DR+NG处理相比,DR+PA处理的放线菌门(Actinobacteriota)、脱硫菌门(Desulfobacterota)、厚壁菌门(Firmicutes)和绿弯菌门(Chloroflexi)相对丰度均呈显著或极显著(P<0.01)上升。不同处理下土壤微生物多样性具有显著差异,与DT+NG处理相比,DR+NG处理的ACE和Chao指数分别上升7.30%和6.90%,Simpson指数极显著上升44.09%(P<0.001),Shannon指数极显著下降2.27%(P<0.001);与DR+NG处理相比,DR+PA处理的ACE、Chao和Shannon指数分别极显著上升13.50%、13.30%和2.80%(P<0.001),Simpson指数极显著下降25.68%(P<0.001)。功能预测结果显示,水稻轮作和生草处理显著影响碳氮循环相关功能,与DT+NG处理相比,DR+NG处理的硝化作用(Nitrification)功能的相对丰度极显著提高103.6%(P<0.01);与DR+NG处理相比,DR+PA处理的化能异养(Chemoheterotrophy)、有氧化能异养(Aerobic chemoheterotrophy)和固氮作用(Nitrogen fixation)功能的相对丰度分别极显著提高17.3%、22.0%和88.3%(P<0.01)。【结论】深翻后轮作一季水稻结合苜蓿生草处理可改善桃园土壤理化性质,为桃树早期生长提供理想的微生物环境,较传统自然生草和单一深翻具有更优的综合改良效果,可在老桃园更新中推广应用。

     

    Abstract:Objective】This study aimed to analyze the effects of different improvement measures on physicochemical properties and bacterial diversity of peach rhizosphere soil, providing theoretical basis for peach continuous crop obstacle alleviation and sustainable development of peach cultivation.【Method】Replanted peach rhizosphere soil was used as the research object. Three treatments were established: deep tillage of original soil followed by rice rotation + natural grass (DR+NG), deep tillage of original soil followed by rice rotation + alfalfa grass (DR+PA), and deep tillage of original soil + natural grass (DT+NG). Soil physicochemical property determination and high-throughput sequencing were used to analyze the composition and diversity of bacterial communities of rhizosphere soil in peach orchard under different improvement measures, and function prediction was performed.【Result】The analysis results of soil physicochemical pro-perty showed that, compared with the DT+NG treatment, the DR+NG treatment significantly increased soil pH, alkali-hydrolyzable nitrogen, and organic matter content (P<0.05, same below), and significantly decreased electrical conductivity and available potassium content. Compared with the DR+NG treatment, the DR+PA treatment significantly decreased soil pH, electrical conductivity, alkali-hydrolyzable nitrogen content, and organic matter content while significantly increased available potassium content. Bacterial community analysis showed that, compared with the DT+NG treatment, the relative abundance of Bacteroidota, Crenarchaeota, Latescibacterota, NB1-j, and Nitrospirota significantly or extremely significantly (P<0.01) increased; compared with the DR+NG treatment, the relative abundance of Actinobacteriota, Desulfobacterota, Firmicutes, and Chloroflexi significantly or extremely significantly (P<0.01) increased. Soil microbial diversity showed significant differences among treatments. Compared with the DT+NG treatment, the ACE and Chao indexes under the DR+NG treatment increased by 7.30% and 6.90% respectively, the Simpson index extremely significantly increased by 44.09% (P<0.001), and the Shannon index extremely significantly decreased by 2.27% (P<0.001); compared with the DR+NG treatment, the ACE, Chao, and Shannon indexes under the DR+PA treatment extremely significantly increased by 13.50%, 13.30%, and 2.80% (P<0.001) respectively, and the Simpson index extremely significantly decreased by 25.68% (P<0.001). Function prediction results showed that rice rotation and grass treatments significantly affected carbon and nitrogen cycling-related functions, and compared with the DT+NG treatment, relative abundance of nitrification function under the DR+NG treatment extremely significantly increased by 103.6% (P<0.01); compared with the DR+NG treatment, relative abundance of chemoheterotrophy, aerobic chemoheterotrophy, and nitrogen fixation functions under the DR+PA treatment extremely significantly increased by 17.3%, 22.0%, and 88.3% respectively (P<0.01).【Conclusion】Deep tillage followed by rice rotation combined with alfalfa grass treatment can improve soil physicochemical properties and provide an ideal microbial environment for early peach growth. Compared with conventional natural grass and deep tillage alone, it shows better comprehensive improvement effects and can be applied in the renewal of old peach orchards.

     

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