石灰与绿肥对连作雪茄烟田土壤理化性质与真菌群落的影响

Effects of lime and green manure on soil physicochemical properties and fungal community in a continuous cropping cigar tobacco field

【目的】明确石灰与绿肥对连作烟田土壤理化性状、土壤微生物量及真菌群落的影响差异,为科学改良连作土壤提供依据。【方法】在湖北来凤县选择连作12年、土壤类型为黄棕壤的雪茄烟田为研究对象,设置施石灰(L)、施石灰+绿肥还田(LGM)、绿肥还田(GM) 3种土壤改良措施和不施石灰+不种绿肥处理(CK),用5点取样法采集耕层(0—20 cm)土样,分析不同措施对土壤理化性状与不同区系微生物数量的差异影响。采用Illumina NovaSeq高通量测序技术和FUNGuild平台分析烟田土壤真菌群落多样性、组成结构、营养型组成及功能类群变化,并比较了不同处理的雪茄烟经济效益。【结果】3种土壤改良措施均不同程度地增加了土壤全氮、有机质、速效钾含量,且以LGM效果最佳,但改善土壤酸化现象则以L效果最佳。L、LGM、GM处理均显著增加细菌与微生物总量,细菌数量分别较CK增加23.22%、68.07%、46.70%,微生物总量分别增加22.06%、62.12%、42.42%,但仅GM处理显著增加土壤中真菌数量,增幅12.25%。3种土壤改良措施均显著影响土壤真菌群落结构,其中GM处理显著增加真菌群落丰富度,相比对照增加15.01%。L处理增加毛霉属(Mucor)的相对丰度,GM处理增加木霉属(Trichoderma)的相对丰度。L、LGM和GM处理均降低病原菌镰刀菌属(Fusarium)在土壤中的相对丰度,降幅分别为19.32%、13.78%和9.71%。LEfSe分析结果显示,相比对照3种土壤改良措施均显著提高土壤中毛壳菌科(Chaetomiaceae)的相对丰度,LGM和GM处理显著提高腐质霉属(Humicola)的相对丰度,L和LGM处理显著提高短梗蠕孢属(Trichocladium)的相对丰度。FUNGuild分析结果表明,3种土壤改良措施均不同程度降低土壤中植物病原真菌的相对丰度,优化真菌的营养型组成结构。L、LGM和GM处理均显著提高雪茄烟的均价、产量与产值,其中产值分别提高14.56%、27.45%、21.47%,且LGM处理的产值显著高于L处理。【结论】3种土壤改良措施均不同程度地提高土壤质量,在增加真菌群落丰富度、提高有益菌属相对丰度、改善真菌营养型组成结构、优化真菌功能类群方面,绿肥还田处理的效果最好,施石灰+绿肥还田或绿肥单独还田提高土壤肥力、增加雪茄烟经济效益的效果要优于单施石灰。

【Objectives】This study aimed to clarify the effects of lime and green manure on soil physical and chemical properties,soil microbial biomass,and fungal community in continuous cropping tobacco fields,and the basis for scientific improvement of continuous cropping soil was provided.【Methods】In Laifeng County,Hubei Province,a 12 year continuous cropping field with yellow brown soil was selected as the research object.Three soil improvement measures,lime(L),lime + green manure(LGM) and green manure(GM),were adopted to collect 0-20 cm soil samples from the tilled layer by 5-point sampling method.The effects of different measures on soil physicochemical properties and microbial biomass of different flora were analyzed.Illumina NovaSeq high-throughput sequencing technology and the FUNGuild platform were used to analyze the differences in soil fungal community diversity,composition structure,nutrient type composition,and functional group division in soil.The economic benefits of cigars produced by different treatments were also compared.【Results】 1) The three soil improvement measures could increase the contents of total nitrogen,organic matter and available potassium to different degrees,and LGM had the best effect on enhancing soil fertility,but L had the most significant effect on improving soil acidification.L,LGM and GM treatments could significantly increase the number of bacteria and the total number of microorganisms in soil,the bacteria increased by 23.22%,68.07%and 46.70%,and the total number of microorganisms increased by 22.06%,62.12% and 42.42%,respectively.However,only GM treatment could significantly increase the number of fungi in soi by 12.25%.2) The three soil improvement measures had significant effects on the soil fungal community structure,and there were significant differences among them.Specifically,the GM treatment could significantly increase the fungal community richness by 15.01% compared to the control.Treatment L could increase the relative abundance of Mucor,treatment GM could increase the relative abundance of Trichoderma,and L,LGM,and GM treatments could reduce the relative abundance of the pathogen Fusarium in soil by 19.32%,13.78% and 9.71%,respectively.3) LEfSe analysis results showed that the relative abundance of Chaetomiaceae in soil could be significantly improved by all three improvement measures.LGM and GM could significantly increase the relative abundance of Humicola,and L and LGM could significantly increase the relative abundance of Trichocladium.4) FUNGuild analysis results indicated that the three improvement measures could reduce the relative abundance of pathogenic fungi and optimize the nutrient composition of fungi.5) The average price,yield,and output value of cigars could be significantly increased by L,LGM and GM treatments,with the output value increasing by 14.56%,27.45%,21.47%,respectively,and the output value of LGM was significantly higher than that of L treatment.【Conclusions】The three soil improvement measures could improve soil to different degrees.The GM treatment is more effective in increasing the richness of the fungal community,increasing the relative abundance of beneficial fungi,improving the nutrient composition of fungi,and optimizing the functional groups of fungi.The effects of LGM and GM treatments on improving soil fertility and the economic benefits of cigars are better than those of the L treatment.