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| Contributions of wheat and maize growth to soil carbon input and output |
| Received:March 11, 2021 |
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| KeyWord:wheat;maize;rhizodeposition;root-derived respiration;rhizosphere priming effect |
| Author Name | Affiliation | E-mail | | SUN Zhaoan | Key Laboratory of Biochemistry and Molecular Biology in University of Shandong, College of Biological and Agricultural Engineering, Weifang University, Weifang 261061, China
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | | | ZHU Biao | Institute of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China | | | ZHANG Yiwen | Agricultural Technology Extension Center of Zhaoyuan Agricultural and Rural Bureau, Zhaoyuan 265499, China | | | LI Mengyu | Key Laboratory of Biochemistry and Molecular Biology in University of Shandong, College of Biological and Agricultural Engineering, Weifang University, Weifang 261061, China | | | MENG Fanqiao | Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China | mengfq@cau.edu.cn |
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| Abstract: |
| In agroecosystem, partitioning exogenous C input and endogenous C release is a prerequisite for quantifying soil C balance. The contribution of different C sources to soil organic C(SOC) and soil CO2 can be accurately distinguished using the C isotope method. This method can not only quantify soil C input in the form of rhizodeposition but can also estimate the rhizosphere priming effects on SOC decomposition, which increases the accuracy of soil C balance assessments. Through a survey of the literature on 13C/14C tracer experiments, the study analyzed photosynthetic C allocation, belowground C input, different contributions of soil CO2 emission, and rhizosphere priming effects. The results showed that the photosynthesized C of wheat allocated to aboveground, roots, SOC, and soil CO 2 emissions were 73.1%, 12.5%, 4.6%, 9.8% of the net assimilated C, respectively, and those of maize were 68.4%, 16.0%, 4.6%, and 11.1%, respectivedly. The amounts of the photosynthetic C transferred into soil were 1 058 kg·hm-2 and 1 025 kg·hm-2 by wheat and maize, among which the contribution of rhizodeposition was 0.45 and 0.38, respectively. The contribution of root-derived respiration to total soil CO2 emissions in wheat- and maize-planted soils accounted for 51.3% and 56.7%, respectively. The growth of wheat and maize showed positive rhizosphere priming effects on SOC decomposition, with average magnitudes of 172% and 15%, respectively. If the traditional root exclusion method was used to distinguish soil respiration, the positive rhizosphere priming effects would be ignored, which might lead to the overestimation of root-derived respiration. The net rhizodeposition during the growth of wheat and maize accounted for 27% and 22% of the net belowground C input(root + rhizodeposition), respectively. If the traditional root washing method was used, rhizodeposition could not be quantified, resulting in an underestimation of the net belowground C input. |
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