川西北高寒沙地红柳灌丛内外有机碳及腐殖质碳组分变化特征

摘要

为了解川西北高寒沙地红柳对土壤有机碳及腐殖质碳组分的影响,选取了沙地上修复24a的红柳灌丛作为研究对象,通过野外调查并结合土壤样品采集和室内分析,研究了川西北沙地红柳灌丛根区(SR)、灌丛中部(SM)、灌丛边缘(SE)、灌丛外部(SO)的0～20,20～40 cm和40～60 cm土层土壤有机碳及腐殖质碳组分变化特征.结果表明:随着距灌丛植株水平距离的增加,土壤有机碳(SoC)、胡敏酸碳(HAC)、富里酸碳(FAG)和胡敏素碳(HMC)含量均呈现下降的特征;0～20 cm表层土壤,灌丛根区、灌丛中部和灌丛边缘土壤有机碳含量分别为灌丛外部的1.86倍、2.35倍和1.63倍,灌丛根区、灌丛中部和灌丛边缘土壤腐殖质碳含量分别为灌丛外部的1.96倍、0.68倍和1.22倍;在距灌丛植株水平距离相同条件下,随土层深度增加,土壤有机碳及腐殖质碳各组分含量呈降低趋势;在灌丛根区,20～40 cm和40～60 cm土层土壤有机碳相对于0～20 cm土层分别降低了32.31％和38.38％,20～40 cm和40～ 60 cm土层土壤腐殖质碳相对于0～20 cm土层分别降低了49.34％和53.40％.研究得出,红柳灌丛内外土壤有机碳及腐殖质碳组分存在空间异质性分布.%In order to identify the effect of organic carbon and humus carbon under or outside the branchy tamarisk canopy in sand land in Northwest Sichuan province,the semi-restored sand with 24-year ecological restoration age was taken as sample.We studied the varying characteristics of soil organic carbon and humus carbon of shrub rhizosphere (SR),shrub middle (SM),shrub edge (SE) and shrub without (SO) at different sand land layers.Field investigation,sample collection and laboratory analysis were employed.The results are as follows.The content of soil organic carbon (SOC),humic acid carbon(HAC),fulvic acid carbon(FAC) and humin carbon(H-MC) decreased with the increase of the horizontal distance from the shrub.The content of SOC in SR,SM,and SE in 0-20cm depth was respectively 1.86,2.35 and 1.63 times of that in SO.HC in SR,SM,and SE in 0 ～ 20 cm depth was respectively 1.96,0.68 and 1.22 times of that in SO.Under the same conditions of the horizontal distance from the shrub,soil organic carbon and humus carbon contents showed a trend of decrease with the increase of soil depth.In SR,SOC in 20 ～ 40 cm and 40 ～ 60 cm soil layer decreased by 32.31％ and 38.38％ respectively compared with 0 ～ 20 cm.HC in 20～40 cm and 40 ～ 60 cm soil decreased by 49.34％ and 53.40％ respectively in relation to the 0 ～ 20 cm soil.We found that spatial heterogeneity of SOC and HC was high.