城市化进程中沈阳城市绿地土壤有机碳储量空间分布研究

Spatial Distribution of Soil Organic Carbon Stocks in Urban Green Space with Urbanization in Shenyang,China

城市绿地土壤是城市绿色生态系统重要组成部分,土壤有机碳是土壤质量关键因素。在沈阳三环区域内对城市绿地土壤(0~20cm)取样269份,分析了土壤的有机碳含量及其空间分布。研究结果表明,沈阳城市绿地SOC浓度与碳密度为24.82g/kg和3.98kg/m2,高于研究区周边的郊区和农村表层土壤;SOC浓度和碳密度具有较大的变异范围,CV值达到40%以上;SOC密度与离城市核心距离呈弱的负相关性;SOC密度在不同土地利用类型中表现差异显著,工业用地SOC密度最高,达到4.99kg/m2,居住用地最低,为2.91kg/m2;城市绿地SOC储量随土壤形成时间推移而不断累积,年代越早,SOC密度越高,20世纪80年代最高,达到5.47kg/m2,21世纪10年代最低,为3.18kg/m2。沈阳城市绿地SOC储存的空间分布有以下特点:城市绿地SOC相较于郊区和农村具有一定富集性;其分布不均匀,具有镶嵌性;在各土地利用类型中分布差异性大;碳储量由城市核心向城市边缘递减。沈阳三环内绿地SOC储量为6.438×105t,获得沈阳三环内城市SOC储量空间分布图。

Soil organic carbon(SOC)is a key factor of soil quality,which is an important component of urban green ecosystem.The SOC stocks and its spatial distribution in the Third Ring Road in Shenyang were studied.269 topsoil samples(0~20cm)were collected.The SOC concentration and density of topsoil were analyzed.Results are shown as follows:the SOC concentration and density were 24.82g/kg and 3.98kg/m2 respectively,which were higher than those of suburban and rural soils.The SOC concentrations and densities had a large variation range,whose coefficients of variance(CVs)were more than 40%.There was a weak negative correlation between the SOC densities and the distances from the urban core.The SOC densities showed significant differences in different land use types.The highest value was in the industrial land,reaching 4.99kg/m2.The lowest one(2.91kg/m2)was in the residential land.Further findings revealed that SOC increased with the built-up ages.The spatial distribution of SOC stocks in urban green space in Shenyang had the following characteristics:the SOC in the urban green space was more abundant than that in the suburb and rural areas;its distribution was uneven and mosaic;the SOC stocks varied in different land use types,and decreased from the urban core to the edge.The SOC stocks(0~20cm)in Shenyang Third Ring Road were estimated to be 6.438×105t.The spatial distribution map of SOC stocks was obtained.