Pedosphere 26(6): 817--828, 2016
ISSN 1002-0160/CN 32-1315/P
©2016 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Assessment of plant-driven mineral weathering in an aggrading forested watershed in subtropical China |
ZUO Shuang-Miao1,2, YANG Jin-Ling1,2 , HUANG Lai-Ming1,2,3, D. G. ROSSITER1,4 and ZHANG Gan-Lin1,2 |
1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
2University of Chinese Academy of Sciences, Beijing 100049 (China)
3Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)
4Section of Crop & Soil Sciences, Cornell University, Ithaca NY14853 (USA) |
| ABSTRACT |
| Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca2+, Mg2+, Na+, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha-1 year-1, respectively. Taking biomass into consideration, weathering rates of Ca2+, Mg2+, and Si and the sum of weathering rates of Ca2+, Mg2+, Na+, K+, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient (e.g., Ca2+, Mg2+, and K+) absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth’s Critical Zone. |
| Key Words: biogeochemistry, biomass, Earth's Critical Zone, geochemical mass balance, nutrient absorption, stoichiometric analysis, vegetation, weathering mechanisms |
| Citation: Zuo, S. M., Yang, J. L., Huang, L. M., Rossiter, D. G. and Zhang, G. L. 2016. Assessment of plant-driven mineral weathering in an aggrading forested watershed in subtropical China. Pedosphere. 26(6): 817-828. |
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