Pedosphere 28(3): 478--487, 2018
ISSN 1002-0160/CN 32-1315/P
©2018 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Soil Macropore Structure Characterized by X-Ray Computed Tomography Under Different Land Uses in the Qinghai Lake Watershed, Qinghai-Tibet Plateau
HU Xia1,2, LI Zongchao1,2, LI Xiaoyan1,2, WANG Pei1,2, ZHAO Yunduo1,2, LIU Lianyou1,3, LÜ Yanli1,3
1State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875(China)
2School of Natural Resources, Faculty of Geographical Science, Beijing Normal University, Beijing 100875(China)
3Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875(China)
Corresponding Author:HU Xia
ABSTRACT
      Quantification of soil macropores is important to enhance our understanding of preferential pathways for water, air, and chemical movement in soils. However, the soil architecture of different land uses is not well understood in elusive alpine regions. The objective of this study was to quantify the architecture of soil macropores in a Kobresia meadow, farmland, and sand in the Qinghai Lake watershed of northeastern Qinghai-Tibet Plateau, China using X-ray computed tomography. Nine soil cores at 0-50 cm depth were collected at three sites with three replicates. At each site, the three collected cores were scanned using a GE HiSpeed FX/i medical scanner (General Electric, USA). To analyze soil architecture, the number of macropores, macroporosity, and mean macropore equivalent diameter within the 50 cm soil profile were determined from the X-ray computed tomography. Analysis of variance indicated that land use significantly influenced macroporosity, mean macropore equivalent diameter, and number of macropores. The soils of the Kobresia meadow and farmland had greater macroporosity and developed deeper and longer macropores than that of sand. For the Kobresia meadow, macropores were distributed mainly in the 0-10 cm soil layer, while they were distributed in the 0-20 cm soil layer for the farmland. The large number of macropores observed in the soils of the Kobresia meadow and farmland could be attributed to greater root development. The results of this study provided improved quantitative evaluation of a suite of soil macropore features with significant implications for non-equilibrium flow prediction and chemical transport modeling in soils.
Key Words:  farmland,Kobresia meadow,macroporosity,root development,sand,soil architecture
Citation: Hu X, Li Z C, Li X Y, Wang P, Zhao Y D, Liu L Y, LÜ Y L. 2018. Soil macropore structure characterized by X-ray computed tomography under different land uses in the Qinghai Lake watershed, Qinghai-Tibet Plateau. Pedosphere. 28(3):478-487.
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