Journal of Geographical Sciences >
Increased soil organic carbon storage in Chinese terrestrial ecosystems from the 1980s to the 2010s
Author: Xu Li, PhD and Assistant Professor, specialized in global carbon cycle. E-mail: xuli@igsnrr.ac.cn
Received date: 2018-03-30
Accepted date: 2018-06-22
Online published: 2019-01-25
Supported by
The Chinese Academy of Sciences Strategic Priority Research Program, No.XDA19020302, National Key Research Project of China, No.2016YFC0500202
National Natural Science Foundation of China,No.31290221, No.41571130043, No.31570471
Copyright
Soil stores a large amount of the terrestrial ecosystem carbon (C) and plays an important role in maintaining global C balance. However, very few studies have addressed the regional patterns of soil organic carbon (SOC) storage and the main factors influencing its changes in Chinese terrestrial ecosystems, especially using field measured data. In this study, we collected information on SOC storage in main types of ecosystems (including forest, grassland, cropland, and wetland) across 18 regions in China during the 1980s (from the Second National Soil Survey of China, SNSSC) and the 2010s (from studies published between 2004 and 2014), and evaluated its changing trends during these 30 years. The SOC storage (0-100 cm) in Chinese terrestrial ecosystems was 83.46 ± 11.89 Pg C in the 1980s and 86.50 ± 8.71 Pg C in the 2010s, and the net increase over the 30 years was 3.04 ± 1.65 Pg C, with an overall rate of 0.101 ± 0.055 Pg C yr-1. This increase was mainly observed in the topsoil (0-20 cm). Forests, grasslands, and croplands SOC storage increased 2.52 ± 0.77, 0.40 ± 0.78, and 0.07 ± 0.31 Pg C, respectively, which can be attributed to the several ecological restoration projects and agricultural practices implemented. On the other hand, SOC storage in wetlands declined 0.76 ± 0.29 Pg C, most likely because of the decrease of wetland area and SOC density. Combining these results with those of vegetation C sink (0.100 Pg C yr-1), the net C sink in Chinese terrestrial ecosystems was about 0.201 ± 0.061 Pg C yr-1, which can offset 14.85%-27.79% of the fossil fuel C emissions from the 1980s to the 2010s. These first estimates of soil C sink based on field measured data supported the premise that China’s terrestrial ecosystems have a large C sequestration potential, and further emphasized the importance of forest protection and reforestation to increase SOC storage capacity.
Key words: Chinese terrestrial ecosystems; change; storage; soil organic carbon
XU Li , YU Guirui , HE Nianpeng . Increased soil organic carbon storage in Chinese terrestrial ecosystems from the 1980s to the 2010s[J]. Journal of Geographical Sciences, 2019 , 29(1) : 49 -66 . DOI: 10.1007/s11442-019-1583-4
Table 1 Eatimates of organic carbon(SOC) density and storage in Chinese terrestrial ecosystems reported in different studies |
Figure 1 Regional division of China’s terrestrial ecosystems and the distribution of soil samples collected in China in the 1980s and 2010s |
Table 2 The properties of soil samples and SOC density (kg C m-2) across different ecosystems of China in the 1980s and 2010s |
1980s | 2010s | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Forest | Grassland | Cropland | Wetland | Others | Forest | Grassland | Cropland | Wetland | Others | ||
0-20cm | N† | 1990 | 1367 | 4175 | 498 | 867 | 1861 | 931 | 840 | 796 | 108 |
Min | 0.04 | 0.13 | 0.05 | 0.14 | 0.09 | <0.01 | 0.03 | 0.28 | 0.18 | 0.11 | |
Max | 15.02 | 16.94 | 17.09 | 57.42 | 12.26 | 13.59 | 13.40 | 7.91 | 23.75 | 6.28 | |
Mean | 3.93 | 3.39 | 2.95 | 7.11 | 2.52 | 4.48 | 4.06 | 3.03 | 5.60 | 1.72 | |
SD | 2.45 | 2.53 | 1.89 | 5.15 | 1.74 | 2.83 | 2.99 | 1.56 | 4.82 | 1.24 | |
CV | 0.62 | 0.74 | 0.64 | 0.72 | 0.69 | 0.63 | 0.74 | 0.51 | 0.86 | 0.72 | |
0-100cm | N | 1989 | 1349 | 4175 | 498 | 867 | 1344 | 842 | 544 | 328 | 89 |
Min | 0.04 | 0.13 | 0.23 | 0.71 | 0.11 | 0.50 | 0.39 | 0.94 | 0.55 | 0.41 | |
Max | 55.87 | 30.84 | 49.89 | 176.17 | 40.98 | 34.66 | 30.01 | 22.44 | 85.12 | 27.50 | |
Mean | 10.11 | 8.56 | 8.49 | 23.80 | 7.06 | 10.12 | 8.23 | 8.16 | 14.87 | 5.96 | |
SD | 6.90 | 6.02 | 5.76 | 19.07 | 4.50 | 6.23 | 5.74 | 4.06 | 14.81 | 5.09 | |
CV | 0.68 | 0.70 | 0.68 | 0.80 | 0.64 | 0.62 | 0.70 | 0.50 | 0.99 | 0.85 |
†N, sample number; Min, Max and Mean, the minimum, maximum, and mean value of SOC density (kg C m-2); SD, standard deviation; CV, the coefficient of variation. |
Figure 2 Flow diagram of soil organic carbon (SOC) storage change calculation during the 1980s-2010s |
Figure 3 SOC density (a, kg C m-2) and storage (b, Pg C) in China during the 1980s-2010s |
Figure 4 SOC density (a, b; kg C m-2) and storage (c, d; Pg C) across different ecosystems of China |
Figure 5 Absolute (a, Pg C) and relative (b, %) changes in soil organic carbon (SOC) storage across different ecosystems of China |
Table 3 Changes in SOC density (kg C m-2) and storage (Pg C) across different ecological regions of China from the 1980s to the 2010s |
Table 4 Changes in SOC density (kg C m-2) and storage (Pg C) across different ecological regions of China from the 1980s to the 2010s (0-20 cm layer) |
Table 5 Changes in SOC density (kg C m-2) and storage (Pg C) across different ecological regions of China from the 1980s to the 2010s (0-100 cm layer) |
Figure 6 Overall terrestrial ecoystems C sink in China, Europe, and the United States |
The authors have declared that no competing interests exist.
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