不同恢复年限内陆盐沼湿地土壤氮含量的差异性分析

Differences of Soil Nitrogen Concentration in the Inland Salt Marsh of Different Restored Years

以向海自然保护区内的自然芦苇湿地为对照、以不同恢复年限芦苇湿地为研究对象,用野外采集土壤样本和室内化验分析的方法获取土壤数据,通过数据分析,探讨了三种不同恢复年限湿地土壤氮素含量差异性及其影响因素,并对相关机理进行了阐释。研究结果表明:(1)土壤全氮含量取自地表向下40 cm深度土层的平均值,恢复1 a、恢复3 a、恢复5 a湿地及自然湿地土壤全氮含量取5月、7月和9月的平均值,分别为312.04、526.22、1305.57和1992.45 mg kg^-1,随着恢复年限的增长土壤氮含量增加并且逐渐接近于自然湿地,恢复5年的湿地土壤氮含量与自然湿地间差异已不明显;(2)季节之间比较,7月土壤氮含量最高,9月次之,5月最低;(3)同一土层剖面不同深度土层比较,0~20 cm土层土壤氮素含量最高,越向下层含量越低;(4)湿地土壤氮含量恢复年限间变异性高于垂直剖面土层间变异性,恢复年限间变异系数介于35.77%至81.63%之间,垂直剖面土层间变异系数介于19.15%至48.76%之间。

The difference of nitrogen(N)concentration and its influencing factors of three different restored years were compared in the Phragmites australis wetland of the Xianghai Nature Reserve.The results showed that:(1)The total N concentration is taken from the average of 40 cm of soil depth down the surface.The total N concentration was averaged in May,July and September.The N concentration in 1-year,3-year,5-year restored wetland and natural wetland was 312.04 mg kg^-1,526.22 mg kg^-1,1305.57 mg kg^-1,and 1992.45 mg kg^-1,respectively.The N concentration was increased gradually with the prolongation of restored years and was close to that of natural wetlands.(2)N concentration and its distribution characteristics down soil profile were affected by seasons.The soil N concentration was the highest in July,followed by September and the lowest in May.Soil N was mainly enriched in the 0-20 cm layer.The deeper the soil layer,the lower the N concentration.(3)The variability of N in wetland soil with restored years was higher than that with soil profile,with a coefficient of variation of 35.77%-81.63%and 19.15%-48.76%,respectively.(4)There was no significant difference in soil N concentration between natural wetland and 5-year restored wetland.Considering only soil N,wetland restoration for 5 years can be close to the level of natural wetland.