黄河三角洲芦苇湿地土壤有机碳储量沿盐分梯度的变化特征

Changes of soil organic carbon storage in Phragmites australis wetlands along a salinity gradient in the Yellow River Delta

以黄河三角洲芦苇湿地为研究对象,于2019年6月自海向陆沿盐分梯度采集土壤和植物样品,研究了不同盐度条件下芦苇湿地土壤有机碳含量和储量的空间分布特征及其与土壤属性和植物地下生物量的关系.结果表明,黄河三角洲芦苇湿地100 cm深土壤有机碳储量为4.46~7.65 kg·m^(-2),平均值为6.24 kg·m^(-2).表层浓度因子值表明研究区土壤有机碳储量主要受植物循环作用的影响.表层(0~30 cm)土壤有机碳含量的变异系数较大,至60 cm时变异趋于稳定.总体上,该区域土壤有机碳主要集中在0~60 cm的土层中,占1 m深土壤有机碳储量的70.69%.植物地下生物量在1.24~2.81 kg·m;范围内,植物地下生物量随着土壤盐度的增加而降低.此外,土壤盐度与30 cm深土壤有机碳含量呈显著负相关(p<0.05);土壤有机碳含量和储量与土壤含水率显著正相关(p<0.05).

Soil and plant samples were collected in Phragmites australis wetlands from sea to land along a salinity gradient in the Yellow River Delta in June 2019 to investigate the spatial distributions of soil organic carbon content and storage and their relationships with soil properties and plant belowground biomass.The results showed that soil organic carbon stock of these Phragmites australis wetlands in the Yellow River Delta ranged from 4.46 to 7.65 kg·m^(-2) in the top 100 cm soil,with an average value of 6.24 kg·m^(-2).Top concentration factor values showed soil organic carbon stock was dominantly controlled by plant cycling.Soil organic carbon contents in the top 30 cm soil exhibited relatively high coefficient of variation,and tended to be stable to the depth of 60 cm.Generally,soil organic carbon in this region was mainly concentrated in the top 60 cm soils,accounting for 70.69%of soil organic carbon in the top 100 cm.Plant belowground biomass in this area varied from 1.24~2.81 kg·m^(-2),and they decreased with increasing salinities.Soil organic carbon content and stock were significantly and positively correlated with soil water content.