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- Song, Zhaoliang, et al.
(author)
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High potential of stable carbon sequestration in phytoliths of China's grasslands
- 2022
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 28:8, s. 2736-2750
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Journal article (peer-reviewed)abstract
- Phytolith carbon (C) sequestration plays a key role in mitigating global climate change at a centennial to millennial time scale. However, previous estimates of phytolith-occluded carbon (PhytOC) storage and potential in China's grasslands have large uncertainties mainly due to multiple data sources. This contributes to the uncertainty in predicting long-term C sequestration in terrestrial ecosystems using Earth System Models. In this study, we carried out an intensive field investigation (79 sites, 237 soil profiles [0-100 cm], and 61 vegetation assessments) to quantify PhytOC storage in China's grasslands and to better explore the biogeographical patterns and influencing factors. Generally, PhytOC production flux and soil PhytOC density in both the Tibetan Plateau and the Inner Mongolian Plateau had a decreasing trend from the Northeast to the Southwest. The aboveground PhytOC production rate in China's grassland was 0.48 x 10(6) t CO2 a(-1), and the soil PhytOC storage was 383 x 10(6) t CO2. About 45% of soil PhytOC was stored in the deep soil layers (50-100 cm), highlighting the importance of deep soil layers for C stock assessments. Importantly, the Tibetan Plateau had the greatest contribution (more than 70%) to the PhytOC storage in China's grasslands. The results of multiple regression analysis indicated that altitude and soil texture significantly influenced the spatial distribution of soil PhytOC, explaining 78.1% of the total variation. Soil phytolith turnover time in China's grasslands was mainly controlled by climatic conditions, with the turnover time on the Tibetan Plateau being significantly longer than that on the Inner Mongolian Plateau. Our results offer more accurate estimates of the potential for phytolith C sequestration from ecological restoration projects in degraded grassland ecosystems. These estimates are essential to parameterizing and validating global C models.
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| 2. |
- Yang, Xiaoming, et al.
(author)
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Spatial distribution of plant-available silicon and its controlling factors in paddy fields of China
- 2021
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In: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 401
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Journal article (peer-reviewed)abstract
- Silicon (Si) is beneficial for rice health and production by alleviating various biotic and abiotic stresses. However, the continual export of grain off-farm may result in Si deficiency for rice plants. The current levels of plant available Si (PASi) in rice paddies in China remain unclear, as do the factors that control PASi content in these soils. We conducted a nationwide sampling campaign across the paddy fields of China between 2016 and 2019, and used calcium chloride extractable Si (Si-CaCl2) and buffered acetate extractable Si (Si-NaAc, pH = 4) to quantify PASi. We show that Si-CaCl2 pool was mainly influenced by mean annual temperature (MAT), soil salinity, soil organic carbon (SOC), mean annual precipitation (MAP), and soil pH, suggesting both pedological and biological control mechanisms. However, the Si-NaAc pool was influenced most by soil pH, MAT and MAP, implying pedological control. Compared to data from the 1990s, the Si-NaAc content decreased by 14.1% on a national scale with an annual decline rate of 0.54%. Based on our investigation, at least 65% of China’s paddy fields are deficient in PASi, which is an increase in area of ~15% over the last 20 years. The principal regions where PASi deficiency was recorded are mainly located in southern China, with the levels of Si deficiency lowering as the paddy fields are located further north. The continual off-site removal of PASi from rice grain and straw will need to be addressed through the use of Si-fertilizers, including organic amendments, to maintain a productive and sustainable rice industry in China.
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