Litter decomposition and the C and N dynamics as affected by N additions in a semi-arid temperate steppe, Inner Mongolia of China
文献类型：SCI/SSCI论文
| 作者 | Peng Q. |
| 发表日期 | 2014 |
| 关键词 | litter decomposition N deposition N level N form C sequestration semi-arid temperate grassland soil organic-matter long-term decomposition nitrogen deposition nutrient release boreal forest phosphorus dynamics enzymatic-activity grazing intensity foliar litter needle litter |
| 英文摘要 | Litter decomposition is the fundamental process in nutrient cycling and soil carbon (C) sequestration in terrestrial ecosystems. The global-wide increase in nitrogen (N) inputs is expected to alter litter decomposition and, ultimately, affect ecosystem C storage and nutrient status. Temperate grassland ecosystems in China are usually N-deficient and particularly sensitive to the changes in exogenous N additions. In this paper, we conducted a 1,200-day in situ experiment in a typical semi-arid temperate steppe in Inner Mongolia to investigate the litter decomposition as well as the dynamics of litter C and N concentrations under three N addition levels (low N with 50 kg N/(hm(2)center dot a) (LN), medium N with 100 kg N/(hm(2)center dot a) (MN), and high N with 200 kg N/(hm(2)center dot a) (HN)) and three N addition forms (ammonium-N-based with 100 kg N/(hm(2)center dot a) as ammonium sulfate (AS), nitrate-N-based with 100 kg N/(hm(2)center dot a) as sodium nitrate (SN), and mixed-N-based with 100 kg N/(hm(2)center dot a) as calcium ammonium nitrate (CAN)) compared to control with no N addition (CK). The results indicated that the litter mass remaining in all N treatments exhibited a similar decomposition pattern: fast decomposition within the initial 120 days, followed by a relatively slow decomposition in the remaining observation period (120-1,200 days). The decomposition pattern in each treatment was fitted well in two split-phase models, namely, a single exponential decay model in phase I (< 398 days) and a linear decay function in phase II (> 398 days). The three N addition levels exerted insignificant effects on litter decomposition in the early stages (< 398 days, phase I; P > 0.05). However, MN and HN treatments inhibited litter mass loss after 398 and 746 days, respectively (P < 0.05). AS and SN treatments exerted similar effects on litter mass remaining during the entire decomposition period (P > 0.05). The effects of these two N addition forms differed greatly from those of CAN after 746 and 1,053 days, respectively (P < 0.05). During the decomposition period, N concentrations in the decomposing litter increased whereas C concentrations decreased, which also led to an exponential decrease in litter C:N ratios in all treatments. No significant effects were induced by N addition levels and forms on litter C and N concentrations (P > 0.05). Our results indicated that exogenous N additions could exhibit neutral or inhibitory effects on litter decomposition, and the inhibitory effects of N additions on litter decomposition in the final decay stages are not caused by the changes in the chemical qualities of the litter, such as endogenous N and C concentrations. These results will provide an important data basis for the simulation and prediction of C cycle processes in future N-deposition scenarios. |
| 出处 | Journal of Arid Land |
| 卷 | 6 |
| 期 | 4 |
| 页 | 432-444 |
| 收录类别 | SCI |
| 语种 | 英语 |
| ISSN号 | 1674-6767 |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/29654]  |
| 专题 | 地理科学与资源研究所_历年回溯文献 |
| 推荐引用方式 GB/T 7714 | Peng Q.. Litter decomposition and the C and N dynamics as affected by N additions in a semi-arid temperate steppe, Inner Mongolia of China. 2014. |
入库方式： OAI收割
来源：地理科学与资源研究所
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