广西珍珠湾三种红树林林分土壤碳氮储量的研究

为了探讨不同红树林林分土壤有机碳(soil organic carbon,SOC)和全氮(total nitrogen,TN)储量空间的分布特征以及与C/N的相关性,该研究以广西防城珍珠湾红树林湿地为对象,通过样地调查取样和实验室分析,测定了SOC和TN的含量以及土壤碳储量的计量,揭示了广西北仑河珍珠湾秋茄、木榄和混交林三种红树林林分SOC和TN储量空间的分布特征以及C/N与SOC和TN的相关性。结果表明:(1)秋茄、木榄和混交林的SOC储量分别为140.73、124.94、144.71 t·hm~(-2),三者无显著性差异(P0.05);木榄和混交林垂直分布特征表现为20～40 cm0～20 cm40～60 cm,秋茄表现为随着土层深度的增加而递减。(2)秋茄、木榄和混交林的TN储量分别为6.49、5.01、5.87 t·hm~(-2),表现为随着土层深度的增加而减少的趋势。(3)秋茄、木榄和混交林的SOC与TN储量之间的相关性极显著(P0.01),相关系数分别为0.924、0.971和0.844,说明SOC与TN之间存在一定的耦合效应。(4)三种林分的C/N比值范围为16.77～24.39,表明有机质主要来源于陆地,木榄和混交林土壤的C/N值与SOC储量有显著的相关性(P0.05),三种林分的C/N比值与TN储量相关性均不显著。(5)三种红树林林分的土壤碳储量均高于我国森林土壤碳储量的平均值,且SOC与TN储量之间的相关性极显著。

Soil carbon and nitrogen storages in three mangrove stands of Zhenzhu Gulf, Guangxi

Inorder to probe the storage and spatial distribution characteristics of soil organic carbon(SOC)and total nitrogen(TN)and the relationship between C/N and SOC and TN in soil of mangrove stands of different ages, SOC, TN contents and soil carbon storage were measured and analyzed, based on plot sampling investigation and laboratory analysis, and storage and spatial distribution characteristics of SOC and TN, and the relationship between C/N and SOC and TN were discovered in soils of three kinds of mangrove stands of Kandelia candel, Bruguiera gymnorrhiza and mixed forests in Zhenzhu Gulf, Beilun River of Guangxi. The results were as follows:(1)The SOC storage of Kandelia candel, Bruguiera gymnorrhiza and mixed forests were 140.73, 124.94, 144.71 t·hm^-2, respectively, and there was no significant differences among them(P<0.05); The SOC storage of Bruguiera gymnorrhiza and mixed forests from the highest to the lowest invertical distribution was 20-40 cm > 0-20 cm > 40-60 cm, and the SOC storage of Kandelia candel decreased with the increase of soil depth.(2)TN storage of Kandelia candel, Bruguiera gymnorrhiza and mixed forests were 6.49, 5.01, 5.87 t·hm^-2, respectively, decreasing with the increase of soil depth.(3)There was a significant correlation between SOC andTN storage in Kandelia candel, Bruguiera gymnorrhiza and mixed forests(P<0.01), and correlation coefficients were 0.924, 0.971 and 0.844, respectively, which indicated that there was coupling effect between SOC and TN.(4)The C/N of three stands ranged from 16.77 to 24.39, indicating that the organic matter mainly came from land. There was a significant correlation between soil C/N and SOC storage in Bruguiera gymnorrhiza and mixed forests(P<0.05), but there was no significant correlation between C/N and TN storage in the three stands.(5)The soil carbon storage of three mangrove stands was higher than the average value of forest soil carbon storage in China, and there was extremely significant correlation between SOC and TN.