广西仙岛公园和沙井红树林土壤碳氮储量的空间分布

Spatial Distribution of Soil Carbon and Nitrogen Stocks in Mangrove Wetland of Xiandao Park and Shajing in Guangxi

通过对广西茅尾海的仙岛公园和沙井红树林土壤有机碳(SOC)、全氮(TN)含量和空间分布特征,以及碳氮比(C/N)与SOC和TN的相关性研究,结果显示,仙岛公园红树林的SOC和TN的平均含量分别为24.5和1.06 g/kg,沙井红树林的SOC和TN平均含量分别为11.9和0.71 g/kg。仙岛公园和沙井红树林的SOC储量分别为181.03和92.4 t/hm2,存在显著性差异(P<0.05),仙岛公园和沙井红树林的TN储量分别为8.23和5.12 t/hm2,SOC和TN储量垂直分布,随土层深度的增加呈先减少后增加的趋势(沙井TN除外)。沙井红树林的SOC与TN储量之间相关性极显著(P<0.01,R=0.947),仙岛公园红树林的SOC与TN储量之间相关系数为0.407。这2个研究地点的C/N值为16.77~24.39,其有机质主要来源于陆地,仙岛公园红树林的C/N值与SOC储量存在显著的相关性(P<0.01),沙井红树林的C/N值与TN储量呈显著负相关(P<0.05)。仙岛公园红树林的SOC储量高于我国森林土壤平均碳储量,显示了红树林土壤较高的固碳能力。

The contents and storage patterns of soil organic carbon(SOC)and total nitrogen(TN),spatial distribution characteristics of SOC and TN,C/N ratios,and correlation between SOC and TN in Xiandao Park and Shajing(Guangxi)mangrove wetlands were assessed.The average SOC and TN contents of the Xiandao Park mangrove wetlands were 24.5 and 1.06 g/kg,respectively,and those of the Shajing mangrove wetlands were 11.9 and 0.71 g/kg,respectively.SOC storage capacities of the Xiandao Park and Shajing mangrove wetlands were 181.03 and 92.4 t/hm2,respectively,and were significantly different(P<0.05).TN storage capacities of Xiandao Park and Shajing mangrove wetlands were 8.23 and 5.12 t/hm2,respectively.The highest-to-lowest vertical distribution of SOC storage at both sites and TN storage at Xiandao Park was 20~40 cm>40~60 cm>0~20 cm,while TN storage at Shajing decreased with increasing soil depth.A significant correlation was observed between SOC and TN contents at Shajing(P<0.01);the correlation coefficient was 0.947.C/N ratio at both sites ranged from 16.77 to 24.39,indicating that the organic matter came primarily from the land.A significant correlation between soil C/N and SOC storage was evident at Xiandao Park(P<0.01),and a significant negative correlation between C/N and TN storage was evident at Shajing(P<0.05).The SOC storage of the Xiandao Park mangrove wetlands was higher than that of Chinese forests,indicating that mangrove soil has a higher carbon sequestration capacity.