Pedosphere 31(6): 839--848, 2021
ISSN 1002-0160/CN 32-1315/P
©2021 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Impacts of land use and salinization on soil inorganic and organic carbon in the middle-lower Yellow River Delta
Yang GUO1,4, Xiujun WANG1, Xianglan LI1, Minggang XU2, Yuan LI3, Haonan ZHENG1, Yongming LUO3, Pete SMITH4
1College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875 (China)
2Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agriculture Sciences, Beijing 100081 (China)
3Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)
4Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU (UK)
ABSTRACT
      Soil inorganic carbon (SIC) is an important reservoir of carbon (C) in arid, semi-arid, and semi-humid regions. However, knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C (SOC) under different land use types in the semi-humid region, particularly in coastal zones impacted by soil salinization. We collected 170 soil samples from 34 profiles across various land use types (maize-wheat, cotton, paddy, and reed) in the middle-lower Yellow River Delta (YRD), China. We measured soil pH, electrical conductivity (EC), water-soluble salts, and SOC and SIC contents. Our results showed significant differences in both SOC and SIC among land use types. The dry cropland (maize-wheat and cotton) soils had significantly higher SOC and SIC densities (4.71 and 15.46 kg C m-2, respectively) than the paddy soils (3.28 and 14.09 kg C m-2, respectively) in the 0–100 cm layer. Compared with paddy soils, reed soils contained significantly higher SOC (4.68 kg C m-2) and similar SIC (15.02 kg C m-2) densities. There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils, but a negative relationship in the paddy soils. On average, SOC and SIC densities under maize-wheat cropping were 15% and 4% lower, respectively, in the salt-affected soils in the middle-lower YRD than the upper YRD. This study indicated that land use types had great influences on both SOC and SIC and their relationship, and salinization had adverse effect on soil C storage in the YRD.
Key Words:  C densities,C stocks,land use type,salt-affected soil,soil salinization
Citation: Guo Y, Wang X J, Li X L, Xu M G, Li Y, Zheng H N, Luo Y M, Smith P. 2021. Impacts of land use and salinization on soil inorganic and organic carbon in the middle-lower Yellow River Delta. Pedosphere. 31(6): 839–848.
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