Soil carbon fractions in grasslands respond differently to various levels of nitrogen enrichments
文献类型：SCI/SSCI论文
| 作者 | Song B. ; Niu S. L. ; Li L. H. ; Zhang L. X. ; Yu G. R. |
| 发表日期 | 2014 |
| 关键词 | Carbon sequestration Grassland Labile carbon Nitrogen addition Microbial biomass Soil carbon fraction northern temperate forests organic-matter microbial biomass terrestrial ecosystems climate-change elevated co2 deposition additions storage sequestration |
| 英文摘要 | Soil contains many different C fractions which have diverse physical and chemical compositions. Examining these differential soil C fractions in response to N enrichment is helpful for better understanding soil C changes under the predominantly increasing N deposition. In this study, we used a field N addition experiment in a grassland to explore the effects of various N enrichment levels on soil C fractions. We conducted a field manipulative experiment which used a Latin square design with six N addition levels of 0, 2, 4, 8, 16 and 32 g N m(-2) year(-1) since 2003 in a semiarid grassland in northern China. Soil samples were collected in August (when plants have the greatest biomass), 2011. We measured C and N concentrations in soil light fraction, microbial biomass, extractable organic matter, heavy fraction, and total soil C and N. The results showed that total soil C and N, and heavy fraction C and N were not significantly affected by N addition after 9 years of treatments. In contrast, different N enrichment levels changed soil light fraction C and N, ranging from 4.3 to 27.7 % and 3.3-30.0 %, respectively. Moreover, both light fraction C and N had a nonlinear relationship with N addition rates, and the threshold for N-induced change in light fraction C and N was near 16 g N m(-2) year(-1) in this semiarid grassland. Increases of soil light fraction C and N primarily resulted from changes in biotic (N-stimulated aboveground biomass) and abiotic (soil temperature, moisture and pH) factors under N enrichment. Soil microbial biomass exponentially declined with increasing N, but extractable organic C showed a positive linear response to N enrichment rates. Changes in microbial biomass C and extractable organic C were primarily due to the reduced soil pH under N addition. Our findings suggest that various soil C fractions differentially respond to elevated N, because different sets of biotic and abiotic factors regulate those fractions under N enrichment. |
| 出处 | Plant and Soil |
| 卷 | 384 |
| 期 | 1-2 |
| 页 | 401-412 |
| 收录类别 | SCI |
| 语种 | 英语 |
| ISSN号 | 0032-079X |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/29612]  |
| 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 | Song B.,Niu S. L.,Li L. H.,et al. Soil carbon fractions in grasslands respond differently to various levels of nitrogen enrichments. 2014. |
入库方式： OAI收割
来源：地理科学与资源研究所
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