不同经营模式山核桃林地土壤pH值、养分与细菌多样性的差异

Difference in pH value and nutrient and bacterial diversity in the Carya cathayensis forest soil under different management models

为探究土壤细菌多样性及其功能对山核桃(Carya cathayensis)经营模式的指导作用,本文采用16S r RNA基因高通量测序技术检测并比较了生态经营和过度经营的山核桃林土壤中的细菌群落,分析了山核桃干腐病发病期干腐病感病指数、土壤pH值、养分与细菌多样性的相关性。结果表明:(1)生态经营山核桃林的感病指数(3.3±3.35)显著低于过度经营山核桃林(81.9±1.27)。(2)生态经营山核桃林土壤pH(6.64±0.06)显著高于过度经营山核桃林(5.80±0.04)。(3)过度经营山核桃林土壤的速效磷、速效钾和速效氮含量分别为18.10±0.58 mg/kg、698.63±11.24mg/kg和227.13±3.81 mg/kg,均分别显著高于三者在生态经营山核桃林土壤中的含量(14.94±0.27 mg/kg、497.13±6.19 mg/kg和195.28±6.01 mg/kg)。(4)生态经营和过度经营山核桃林土壤分别有14和21个主要细菌属,其中鞘氨醇单胞菌属(Sphingomonas)、Gaiella和溶杆菌属(Lysobacter)为生态经营山核桃林土壤的优势属,其相对多度显著高于过度经营山核桃林;而Bryobacter、Candidatus Solibacter和慢生根瘤菌属(Bradyrhizobium)为过度经营山核桃林土壤中的优势属,其相对多度显著高于生态经营山核桃林。两种经营模式下山核桃林土壤的OTUs、Ace指数、Chao指数、Shannon指数和Simpson指数无显著差异。RDA分析与蒙特卡罗检验表明,p H值、速效磷和速效氮均对土壤细菌优势菌群群落结构有显著影响(P<0.05)。

To optimize management of the Carya cathayensis forest through the diversity and function of soil bacteria, disease index, soil p H, and nutrient and soil bacterial diversity were investigated under ecological management and excessive management during the Botryosphaeria dothidea infected period using 16 S r RNA gene high-throughput sequencing technology. The correlations between each interrelationship factors were also analyzed. Results showed that the disease index of the ecologically managed forest was 3.3±3.35, which was significantly lower than that of the excessively managed forest with 81.9±1.27. Moreover, ecological management significantly improved the ability of hickory forest resistant to B. dothidea. The soil p H value of the ecologically managed forest was near neutral with a reading of 6.64±0.06, which was significantly higher than that of excessively managed forest soil with 5.80±0.04. The contents of available phosphorus, available potassium, and available nitrogen in the excessively managed forest soil were 18.10±0.58 mg/kg, 698.63±11.24 mg/kg and 227.13±3.81 mg/kg, which were significantly higher than those in the ecologically managed forest respectively, with 14.94±0.27 mg/kg, 497.13±6.19 mg/kg and 195.28±6.01 mg/kg. There were 14 and 21 major bacterial genera found in the ecologically and excessively managed forest soil samples, respectively. In ecologically managed forest soils, the dominant genera were Sphingomonas, Gaiella and Lysobacter, and the relative abundance of these was significantly higher than excessively managed forest soils. Bryobacter, Candidatus Solibacter, and Bradyrhizobium were the dominant genera in the excessively managed forest soils, and their relative abundance was significantly higher than the ecologically managed forest soils. There was no significant difference of OTUs or Ace, Chao, Shannon and Simpson indices between ecologically and excessively managed forest soils. Redundancy analysis（RDA） and Monte Carlo testing showed that pH value, available phosphorous and available nitrogen had significant effects on the bacterial flora of the dominant bacterial species in the soil（P 〈 0.05）. Our results can provide valuable references for the sustainable management of hickory forests.