黄土丘陵区水蚀坡面土壤有机碳矿化动态模拟  

Modelling the dynamics of soil organic carbon mineralization on water-eroded sloping land in the Loess Hilly Region

作　　者：张亚锋[1,2] 许明祥[1,3] 陈盖[3] 王超华[3] 

机构地区：[1]中国科学院水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [2]中国科学院大学,北京100049 [3]西北农林科技大学林学院,陕西杨凌712100

出　　处：《中国水土保持科学》2016年第4期9-17,共9页Science of Soil and Water Conservation

基　　金：国家自然科学基金“黄土高原深层土壤有机碳固存及对土地利用/覆被变化的响应”(41171422),“黄土区生物结皮坡面产汇流过程研究”(40971174);中国科学院战略性先导科技专项“西北农田土壤固碳潜力与速率研究”(XDA05050504)

摘　　要：为了深入理解侵蚀影响下的碳排放机制,本文以黄土丘陵区不同有机碳背景的水蚀坡面土壤为研究对象,采用3因素(土壤有机碳水平、温度和土壤含水量)4水平的正交试验设计,通过对坡面不同部位土壤的室内矿化培养实验,分析水蚀坡面土壤有机碳矿化特征,并模拟土壤有机碳矿化动态。结果表明:土壤有机碳质量分数是影响水蚀坡面有机碳矿化的主要因素,不同有机碳背景下,水蚀坡面表现出不同有机碳矿化特征。当土壤有机碳水平较低时,坡面侵蚀促进了沉积区土壤有机碳矿化;当土壤有机碳水平较高时,沉积区土壤有机碳矿化受到抑制。一级动力学方程较好的描述土壤有机碳矿化累积动态(R>0.98),有机碳矿化潜力(Cp值)能综合反映土壤有机碳水平、温度和含水量对有机碳矿化的影响。通过Cp值修正,得到的土壤有机碳矿化多因素方程拟合度较高(R2>0.95),能够很好地拟合不同有机碳水平下土壤有机碳矿化动态。[Background] In order to understand the mechanism of soil carbon emission under soil erosion,we chose the study area located in Ansai County of Shaanxi Province. It is a typical loess hilly and gully region where annual precipitation distribution is not even,precipitation on July-September accounts for about 60% of annual rainfall,and most are heavy rainstorms. The zonal soil is dark loessial one that lost completely due to serious soil erosion,thus soil is mainly loessial one（ calcareous ustic cambisols） developed from parent-soil loess. As one of the most serious water erosion area all over the world,the selected area is suitable for exploring erosion induced carbon emission. [Methods]Based on the orthogonal experiment design with three factors（ soil organic carbon（ SOC） level,soil temperature,and water content） and four levels of the factors,incubation experiment for soil mineralization wasconducted with soil sampled at different slope positions of a water-eroded sloping land under different soil organic carbon background in the Loess Hilly Region. Random sampling method was used to collect samples in the positions of water-eroded sloping land（ control area,eroded area and deposition area）.The dynamic characteristics of SOC mineralization were analyzed and modelled. [Results] 1） SOC level, soil temperature and soil water content affected significantly the mineralization rate and accumulated mineralization amount of SOC（ P〈0. 05）. The primary and secondary relation of the three variables was： SOC level 〉soil temperature 〉soil water content. 2） Based on the first-order kinetic equation,which could well describe the accumulation dynamics of soil organic carbon mineralization,a multi-factor equation with high fitting degree was obtained by modifying the Cpvalue（ R2〉0. 95）.[Conclusions]1） Soil organic carbon content was one of the main factors affecting the soil organic carbon mineralization at different slope positions. The response of soil organic carbon mineralization to s

关 键 词：土壤有机碳 水蚀坡面 矿化动态 影响因素 模拟 

分 类 号：S153.621[农业科学—土壤学]