不同坡位柑橘园土壤团聚体矿物结合态有机碳矿化特征  

Mineralization Characteristics of Mineral-associated Organic Carbon in Citrus Orchards Soil Aggregates at Different Slope Positions

作　　者：唐开钊 张君耀 吴聪 王帅[1] 廖文娟 尹力初[1] 周卫军[1] 崔浩杰 TANG Kaizhao;ZHANG Junyao;WU Cong;WANG Shuai;LIAO Wenjuan;YIN Lichu;ZHOU Weijun;CUI Haojie(College of Resources,Hunan Agricultural University,Changsha 410128,China)

机构地区：[1]湖南农业大学资源学院,长沙410128

出　　处：《土壤学报》2024年第6期1639-1652,共14页Acta Pedologica Sinica

基　　金：国家现代农业产业技术体系建设专项(CARS-26)。

摘　　要：矿物结合态有机碳(MAOC)是土壤有机碳(SOC)的主要组成部分,其矿化特性对土壤固碳和全球气候变化具有重要影响。坡位作为重要的地形因子,显著影响有机碳与土壤矿物的相互作用及稳定性。然而,目前关于不同坡位土壤MAOC矿化特征尚不清楚。本研究以南方丘陵区典型柑橘园土壤为研究对象,通过室内培养探究了不同坡位(坡上、坡中和坡下)柑橘园土壤团聚体MAOC的矿化特征,分析了土壤理化因子和疏水性对MAOC矿化的影响。结果表明:坡下柑橘园土壤MAOC的累积矿化量(C_(t))、矿化速率和潜在可矿化量(C_(o))均明显高于坡上和坡中,但坡下土壤C_(o)/MAOC的比值明显低于坡上和坡中。随着团聚体粒径的减小,各坡位柑橘园土壤MAOC的C_(t)、矿化速率和C_(o)均呈上升的变化趋势,而MAOC的矿化强度逐渐减弱。冗余分析(RDA)表明,MAOC潜在可矿化量(C_(o))与pH、SOC、MAOC、TN和C/N呈显著正相关(P<0.05),与铁铝氧化物(Fed/Ald、Feo/Alo和Fep/Alp)和疏水性呈显著负相关(P<0.05)。C_(o)/MAOC与铁铝氧化物和MAOC疏水性呈显著正相关,而与C_(o)、C_(t)、pH、SOC、MAOC、TN和C/N呈显著负相关。层次分割分析表明,Alo、Alp和Fep是影响MAOC矿化的重要因子。变差分解分析表明,Alo、Alp、Fep、C/N、MAOC和Feo的共同作用显著影响不同坡位团聚体中MAOC的矿化。研究结果对深入认识南方丘陵区不同坡位柑橘园土壤团聚体中矿物结合态有机碳形成机制、稳定特性以及提高土壤固碳具有重要意义。【Objective】Mineral-associated organic carbon(MAOC)is the most important of soil organic carbon(SOC),and its mineralization characteristics have an important impact on soil carbon sequestration and global climate change.As an important topographic factor,slope position significantly affects the interaction and stability of organic carbon and soil minerals.However,the influence of slope positions on mineralization characteristics of MAOC in soils is not fully understood.【Method】In this study,typical citrus orchard soils at different slope positions were sampled,and the aggregates with sizes of>2,2~0.25,0.25~0.053,and<0.053 mm were obtained by physical fractionation.Moreover,the MAOC in aggregates were separated to investigate the mineralization characteristics of MAOC at varying slope positions(upper slope,middle slope,and lower slope)through indoor cultivation.The influence of soil physicochemical factors and hydrophobicity on MAOC mineralization was analyzed by Infrared spectroscopy(FTIR),Redundancy analysis(RDA),and Hierarchical partitioning analysis.【Result】The results showed that the cumulative mineralization(C_(t)),mineralization rate and potential mineralization(C_(o))of MAOC in citrus orchard soil at lower slopes were significantly higher than those at upper and middle slopes,but the ratio of C_(o)/MAOC at lower slope was significantly lower compared with upper and middle slopes.With the decrease in aggregate size,the C_(t),mineralization rate,and C_(o) of MAOC in citrus orchard soil at each slope position showed an upward trend,while the mineralization intensity of MAOC gradually weakened.RDA results showed that the C_(o) was significantly positively correlated with pH,SOC,MAOC,TN,and C/N(P<0.05),and significantly negatively correlated with iron and aluminum oxides(Fed/Ald,Feo/Alo,and Fep/Alp)and hydrophobicity(P<0.05).C_(o)/MAOC was significantly positively correlated with iron and aluminum oxides and hydrophobicity,but significantly negatively correlated with C_(o),C_(t),pH,SOC,MAOC,TN,and C/

关 键 词：矿物结合态有机碳 土壤团聚体 矿化 疏水性 柑橘园土壤 

分 类 号：S153[农业科学—土壤学]