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在江苏盐城新洋港互花米草(Spartina alterniflora)盐沼选择光滩(MF),互花米草入侵1a(SAF-1),3a(SAF-3),5a(SAF-5)和12a(SAF-12)样地,采集0—20 cm表层土壤样品,分别测定土壤有机碳(SOC)、顽固性有机碳(RC)和活性有机碳(LC)含量,碳氮比(C/N),土壤有机碳和顽固性有机碳的δ13C值,分析互花米草海向入侵过程中土壤有机碳组分、分布及来源变化。结果表明:(1)SOC、RC、LC含量分别介于0.82—7.60 mg/g,0.58—4.02 mg/g和0.23—3.58 mg/g,由海向陆呈递增趋势:SAF-5>SAF-12>SAF-3>MF>SAF-1。入侵12 a的SAF-12样地表土SOC储量最大,年均碳汇积累速率为1.8 t/hm2。(2)互花米草来源SOC、RC和LC含量分别为0.06—3.01 mg/g、0.04—1.06 mg/g和0.03—2.00 mg/g,各占5.75%—47.40%、6.77%—31.77%和3.20%—64.40%。互花米草来源SOC、RC、LC由海向陆均呈递增趋势:SAF-12>SAF-5>SAF-3>SAF-1>MF。(3)互花米草植物来源SOC、RC、LC含量、比例与入侵时间显著正相关(P<0.01)。互花米草入侵对LC的影响较大,对RC的影响较小。(4)随着入侵时间的增长,互花米草来源有机碳的输入显著改变了土壤SOC组分。以上结果表明,短期内互花米草海向入侵能够提高土壤碳汇能力。
Light field (SAF-1), 3a (SAF-3), 5a (SAF-5) and 12a (SAF-1) were selected in the salt marsh of Spartina alterniflora in Yancheng, Jiangsu Province. (SOC), intractable organic carbon (RC) and active organic carbon (LC), carbon / nitrogen ratio (C / N) , Δ13C values of soil organic carbon and intractable organic carbon, and analyzed the changes of soil organic carbon components, distribution and sources during the invasion of Spartina alterniflora. The results showed that: (1) The contents of SOC, RC and LC ranged from 0.82-7.60 mg / g, 0.58-4.02 mg / g and 0.23-3.58 mg / g, respectively. 12> SAF-3> MF> SAF-1. The SAF-12-like topsoil with the 12-year invasion had the largest SOC reserves with annual average carbon sink accumulation rate of 1.8 t / hm2. (2) The SOC, RC and LC contents of Spartina alterniflora were 0.06-3.01 mg / g, 0.04-1.06 mg / g and 0.03-2.00 mg / g respectively, accounting for 5.75% -47.40%, 6.77% -31.77% And 3.20% -64.40%. The SOC, RC and LC of Spartina alterniflora showed an increasing trend from sea to land: SAF-12> SAF-5> SAF-3> SAF-1> MF. (3) The contents of SOC, RC and LC in Spartina alterniflora plants were significantly and positively correlated with the invasion time (P <0.01). Spartina alterniflora has a greater impact on LC but less on RC. (4) As the invasion time increased, the input of SOC from Spartina alterniflora significantly changed the soil SOC content. The above results show that in the short term, Spartina alterniflora invasion can increase soil carbon sink capacity.