期刊
SOIL BIOLOGY & BIOCHEMISTRY
卷 133, 期 -, 页码 97-107出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.soilbio.2019.02.019
关键词
Belowground assimilate allocation; Carbon cycling; Carbon sequestration; Carbon isotope labeling; Rhizodeposition and root exudation; Rice production
类别
资金
- National Key Research and Development Program [2016YFE0101100]
- Australia-China Joint Research Centre Healthy Soils for Sustainable Food Production and Environmental Quality [ACSRF48165]
- National Natural Science Foundation of China [41671253, 41601305, 41807089, 41761134095]
- China Postdoctoral Science Foundation [2017M612573]
- International Postdoctoral Exchange Fellowship Program for 2018 [20180017]
- Hunan Province Base for Scientific and Technological Innovation Cooperation [2018WK4012]
- Chinese Academy of Sciences President's International Fellowship Initiative [2018VCA0031]
- Youth Innovation Team Project of ISA, CAS [2017QNCXTD_GTD]
- RUDN University program 5-100
Knowledge of belowground C input by rice plants and its fate is essential for managing C cycling and sequestration in paddy soils. Previous reviews have summarized C input and the pathways of root-derived C in upland soils by labeling with C-14 or C-13(C-13(/)14), while rice rhizodeposition and C input in paddy soils have not been comprehensively evaluated. Here, we analyzed the results of C-13(/)14 pulse and continuous labeling studies using 112 datasets from 13 articles on the allocation and pathways of photosynthesized C by rice plants to assess C input, budget, and amount stabilized in paddy soils. Overall, C-13(/)14 partitioning estimated by continuous labeling was 72% to the shoots, 17% to the roots, 10% to the soil, and 1.3% was recovered in microbial biomass. Pulse-labeling studies showed a similar C partitioning: 79%, 13%, 5.5%, and 2.1%, respectively. The total belowground C input estimated based on continuous labeling was 1.6 Mg ha(-1) after one rice season, of which rhizodeposition accounted for 0.4 MgC ha(-1). Carbon input assessed by pulse labeling was slightly lower (total belowground C input, 1.4 Mg ha(-1); rhizodeposition, 0.3 MgC ha(-1); 14 days after labeling). Rice C input after one cropping season was lower than that by upland plants (cereals and grasses, 1.5-2.2 Mg ha(-1)). In contrast to upland crops, most paddy systems are located in the subtropics and tropics and have two or three cropping seasons per year. We conclude that (1) pulse labeling underestimates the total belowground C input by 15%, compared with that by continuous labeling, and (2) rhizodeposition of rice accounts for approximately 26% of the total belowground C input, regardless of the labeling method used. Based on allocation ratios, we suggest a simple and practical approach for assessment of the gross C input by rice into the soil, for partitioning among pools and for long-term C stabilization in paddies.
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