引用本文:张 祎,李 鹏,肖 列,赵宾华,时 鹏.黄土高原丘陵区地形和土地利用对土壤有机碳的影响[J].土壤学报,2019,56(5):1140-1150.
ZHANG Yi,LI Peng,XIAO Lie,ZHAO Binhua,SHI Peng.Effects of Topography and Land Use on Soil Organic Carbon in Hilly Region of Loess Plateau[J].Acta Pedologica Sinica,2019,56(5):1140-1150
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黄土高原丘陵区地形和土地利用对土壤有机碳的影响
张 祎, 李 鹏, 肖 列, 赵宾华, 时 鹏
西安理工大学, 西北旱区生态水利工程国家重点实验室培育基地
摘要:
土壤有机碳(SOC)作为土壤中重要的组成部分及植物生长的主要元素,在地球生态系统中起着举足轻重的作用,是全球环境尤其是气候变化的重要影响因素。以黄土高原王茂沟小流域为研究对象,通过间隔为150 m经纬网格分5层采集0~100 cm土壤样品,采集土壤样品包括4种地形(坡顶、坡上、坡中、坡下)和5种土地利用类型(坡耕地、林地、草地、灌木、梯田),共采集土壤样品1 540个,探讨地形和土地利用方式对黄土丘陵沟壑区小流域SOC含量和分布影响,并通过Kriging插值计算流域内SOC空间分布。结果表明,黄土丘陵第一副区王茂沟小流域在0~100 cm土层中,SOC平均含量坡上(4.49 g•kg-1)和坡中(4.30 g•kg-1)含量最高,其次为坡下(3.97 g•kg-1),坡顶SOC含量最低(3.34 g•kg-1);坡耕地SOC含量最低。林地(4.31 g•kg-1)、梯田(4.25 g•kg-1)、草地(4.12 g•kg-1)和灌木(3.82 g•kg-1)分别较坡耕地(3.47 g•kg-1)SOC含量增加24.2%、22.4%、18.7%和10.1%。表层SOC更易受到环境因子的影响,梯田等水土保持措施可明显固存深层(>20 cm)SOC。方差成分估计表明,土地利用、地形、深度以及土地利用与地形的交互作用对流域剖面SOC含量空间分布有着极显著的影响(P <0.01),其中地形对SOC含量的贡献率最高(32.50 %)。土地利用与地形的交互作用在各因子的交互作用中表现出对SOC含量变异解释度最高(7.4 %)。流域SOC在空间上呈斑块分布,随着深度的增加,流域SOC的空间分布向均一性发展。研究结果为黄土区水土保持措施规划及退耕还林的固碳效益评价提供了科学依据。
关键词:  黄土丘陵区  土壤有机碳  地形  土地利用
DOI:10.11766/trxb201901220367
分类号:
基金项目:国家自然科学基金项目(41701603,41601092)、陕西省技术创新引导专项(2017CGZH-HJ-06)
Effects of Topography and Land Use on Soil Organic Carbon in Hilly Region of Loess Plateau
ZHANG Yi, LI Peng, XIAO Lie, ZHAO Binhua, SHI Peng
State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi’ an University of Technology
Abstract:
【Objective】As an important component of agricultural soil a major element for plant growth, soil organic carbon (SOC) plays an important role in the earth ecosystem. Huge amounts of organic carbon are stored in the soil, and even a minor change in soil carbon could significantly change the concentration of CO2 in the atmosphere, which drives global climate change. How SOC is distributed and stored is a very important factor affecting soil quality and SOC fixation.【Method】In this study, soil samples were collected from 5 soil layers in each of the 0~100cm soil profiles distributed in a 150m rectangular grid pattern in fields different in slope position (slope top, upper slope, middle slope, and down slope) and in land use (cultivated land, forest land, grassland, shrubland, terrace) in the Wangmaogou watershed of the Loess Plateau. A total of 1080 soil samples were gathered for analysis of how topographies and land use patterns infuence on content and distribution of SOC via Kriging interpolation.【Result】 Among the slope positions, the upper slopes were the highest, (4.49g•kg-1) and followed by the middle slopes (4.30g•kg-1), the down slopes (3.97 g•kg-1)and slope tops (3.34 g•kg-1) in average SOC content of the 0~100cm soil profiles, while among the land use patterns. the forest land (4.31 g•kg-1) was the highest, and followed by the terraced field (4.25 g•kg-1), grassland (4.12 g•kg-1), shrub land (3.82 g•kg-1) and cultivated land (3.47g•kg-1). Obviously the forest land, terraces, grassland and shrub land was 24.2%, 22.4%, 18.7% and 10.1%, respectively, higher than the cultivated land. SOC in the topsoil was more susceptible to environmental factors, like terracing and some other soil erosion control practices, which can obviously sequestrate SOC in the deep soil layers (>20 cm). Variance component estimation shows that interactions between land use, topography, depth, land use and topography had extremely significant influences on spatial distribution of SOC content (P <0.01). Topography contributed the most to total SOC, reaching 32.50%. And interactions between land use & topography explained 7.4% of the variability of SOC. Spatially, SOC was distributed in patch and increased with depth in the watershed, and turned to be homegeneeous in distribution. 【Conclusion】All the findings in this study may serve as theoretical foundations for water and soil conservation and evaluation of carbon sequestration effects.
Key words:  Loess Hilly Region  Soil organic carbon  Topographies  Land uses