Pedosphere 31(1): 191--203, 2021
ISSN 1002-0160/CN 32-1315/P
©2021 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Interactive effects of elevated CO2 and nitrogen fertilization levels on photosynthesized carbon allocation in a temperate spring wheat and soil system |
Yu ZHAO1,2, Chao LIANG1, Shuai SHAO1,2, Jie LI1, Hongtu XIE1, Wei ZHANG1, Fusheng CHEN3, Hongbo HE1 , Xudong ZHANG1 |
1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016(China)
2University of Chinese Academy of Sciences, Beijing 100049(China)
3Jiangxi Provincial Key Laboratory of Silviculture, Jiangxi Agricultural University, Nanchang 330045(China) |
| ABSTRACT |
| Increasing atmospheric CO2 concentration impacts the terrestrial carbon (C) cycle by affecting plant photosynthesis, the flow of photosynthetically fixed C belowground, and soil C pool turnover. For managed agroecosystems, how and to what extent the interactions between elevated CO2 and N fertilization levels influence the accumulation of photosynthesized C in crops and the incorporation of photosynthesized C into arable soil are in urgent need of exploration. We conducted an experiment simulating elevated CO2 with spring wheat (Triticum aestivum L.) planted in growth chambers. 13C-enriched CO2 with an identical 13C abundance was continuously supplied at ambient and elevated CO2 concentrations (350 and 600 μmol mol-1, respectively) until wheat harvest. Three levels of N fertilizer application (equivalent to 80, 120, and 180 kg N ha-1 soil) were supplied for wheat growth at both CO2 concentrations. During the continuous 62-d 13CO2 labeling period, elevated CO2 and increased N fertilizer application increased photosynthesized C accumulation in wheat by 14%-24% and 11%-20%, respectively, as indicated by increased biomass production, whereas the C/N ratio in the roots increased under elevated CO2 but declined with increasing N fertilizer application levels. Wheat root deposition induced 1%-2.5% renewal of soil C after 62 d of 13CO2 labeling. Compared to ambient CO2, elevated CO2 increased the amount of photosynthesized C incorporated into soil by 20%-44%. However, higher application rates of N fertilizer reduced the net input of root-derived C in soil by approximately 8% under elevated CO2. For the wheat-soil system, elevated CO2 and increased N fertilizer application levels synergistically increased the amount of photosynthesized C. The pivotal role of plants in photosynthesized C accumulation under elevated CO2 was thereby enhanced in the short term by the increased N application. Therefore, robust N management could mediate C cycling and sequestration by influencing the interactions between plants and soil in agroecosystems under elevated CO2. |
| Key Words: C cycling,C sequestration,continuous 13C-enriched CO2 labeling,growing season,isotope composition,N management,wheat tissue biomass |
| Citation: Zhao Y, Liang C, Shao S, Li J, Xie H T, Zhang W, Chen F S, He H B, Zhang X D. 2021. Interactive effects of elevated CO2 and nitrogen fertilization levels on photosynthesized carbon allocation in a temperate spring wheat and soil system. Pedosphere. 31(1): 191-203. |
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