退耕还湖后菜子湖湿地土壤剖面有机碳分布变化

Changes of Distribution of Organic Carbon in Soil Profiles of Wetlands Recovered from Farmlands to Lakes in Caizi Lake

退耕还湖是我国长江中下游地区湿地生态恢复的重要举措,土壤有机碳是评价湿地生态功能恢复的重要组成部分。本文选取菜子湖区不同退耕年限（2、5、8、10、20a）和退耕后不同植被群落（苔草、芦苇和酸模）湿地土壤为研究对象,揭示退耕还湖后退耕年限和植被类型对湿地土壤有机碳恢复的影响。结果表明：随退耕年限的增加,湿地土壤有机碳含量逐渐增加,但土壤有机碳密度随退耕年限增加呈＂升高―降低―升高＂的趋势,总体比油菜地高出61.5%～82.3%;不同植被类型下土壤剖面（0～55 cm）有机碳含量表现为：芦苇（8.90g/kg）〉苔草（8.84g/kg）〉酸模（5.84g/kg）,芦苇土壤剖面有机碳含量随土层深度增加而变化幅度小于苔草和酸模;不同植被类型下土壤剖面（0～55 cm）有机碳密度呈现出芦苇（7.92 kg/m^2）〉苔草（7.42 kg/m^2）〉酸模（5.01 kg/m^2）。结果分析表明退耕还湖后菜子湖湿地植被恢复和理化性质变化促进土壤有机碳含量及其密度变化,而苔草、芦苇和酸模土壤剖面土壤有机碳恢复不一致,芦苇对土壤剖面有机碳密度提升能力最强。

Recovery from far mlands to lakes is an important measure to recover wetlands in the middle and lower reaches of Yangtze River. Soil organic carbon is an important ecological index in assessing the degree of degraded wetland recovery. It is estimated in wetlands with different restoration ages（2, 5, 8, 10, 20a） and different vegetation types（Phragmites australis, Carex maximowiczii and Rumex acetosa Linn） in Caizi Lake.The results show that soil organic carbon contents in wetlands increase with restoration ages while density of soil organic carbon is higher than this in rape field, with ＂increasing-decreasing-increasing＂ tendency,generally 61.5% ～82.3% higher compared with rape fields. Soil organic carbon contents and density of soil organic carbon in 0～55 cm soil profiles show Phragmites australis（8.90g/kg） Carex maximowiczii（8.84g/kg） Rumex acetosa Linn（5.84g/kg） and Phragmites australis（7.92 kg/m^2） Carex maximowiczii（7.42 kg/m^2） Rumex acetosa Linn（5.01 kg/m^2） respectively. With wetland restoration ages, vegetations and physochemical properties recovery induce increase of density soil organic carbon, and Phragmites australis present the strongest ability to increase density of soil organic carbon in Caizi Lake.