互花米草入侵对土壤理化性质及养分含量的影响

Influence of Spartina alterniflora Loisel.Invasion on Soil Physicochemical Properties and Nutrient Content

互花米草作为外来入侵物种,其大量繁殖严重影响了湿地土壤结构和养分含量,危害湿地生态系统的稳定性。通过野外调查收集了天津北大港湿地自然保护区不同入侵程度的互花米草土壤,并测定了土壤绝对含水率、pH值、电导率和容重4种理化指标和总碳含量、总氮含量和总磷含量3种养分含量指标,结果表明:就理化性质而言,互花米草入侵对土壤绝对含水率无显著影响,但可显著影响土壤pH值、电导率和容重;互花米草入侵后,土壤pH值显著下降,土壤电导率显著升高,土壤容重显著降低;就养分含量而言,互花米草入侵对土壤总碳含量、土壤总氮含量和土壤总磷含量均存在显著影响;完全入侵阶段土壤的总碳含量、总氮含量和总磷含量均最高;从土壤氮、磷、钾化学计量学特征来看,互花米草入侵对土壤C/N和土壤N/P均存在显著影响,完全入侵阶段的土壤C/N最大,未入侵阶段和初步入侵阶段的N/P相对较高。

As an alien invasive species,the rapid proliferation of Spartina alterniflora Loisel.has severely impacted wetland soil structure and nutrient content,posing a threat to the stability of wetland ecosystems.In this study,soil samples of Spartina alterniflora Loisel.at different invasion levels were collected through field investigations in Tianjin Beidagang Wetland Nature Reserve.Four physicochemical indicators including soil moisture content,pH value,electrical conductivity,bulk density,and three nutrient content indicators including total carbon,total nitrogen,and total phosphorus were measured.The results showed that Spartina alterniflora Loisel.invasion had no significant effect on soil moisture content,but significantly influenced soil pH value,electrical conductivity,and bulk density.Following the invasion of Spartina alterniflora Loisel.,soil pH value significantly decreased;soil electrical conductivity significantly increased,and soil bulk density significantly decreased.Regarding nutrient content,Spartina alterniflora invasion had a significant impact on total carbon,total nitrogen,and total phosphorus in the soil.The fully invaded stage exhibited the highest levels of total carbon,total nitrogen,and total phosphorus.Analysis of soil nitrogen,phosphorus,and potassium stoichiometry indicated that Spartina alterniflora Loisel.invasion significantly affected soil C/N and soil N/P ratios,with the highest soil C/N ratio observed in the fully invaded stage and relatively higher N/P ratios in the non-invaded and preliminary invasion stages.