| 内蒙古典型草原季节性冻土区土壤剖面CO2、N2O特征 |
| 摘要点击 1541 全文点击 602 投稿时间：2017-09-20 修订日期：2017-10-30 |
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| 中文关键词 冻融作用 典型草原 土壤剖面 温室气体 放牧 |
| 英文关键词 freeze-thawing typical steppe soil profile greenhouse gas grazing |
| 作者 | 单位 | E-mail | | 李晋波 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | 453768869@qq.com | | 姚楠 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | | | 李秀 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | | | 赵英 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | yzhaosoils@gmail.com | | 张阿凤 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | | | 兰志龙 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | | | 范庭 | 西北农林科技大学资源环境学院, 农业部西北植物营养与农业环境重点实验室, 杨凌 712100 | |
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| 中文摘要 |
| 为了评估放牧对内蒙古典型草原季节性冻土区温室气体产生机制的影响，通过气体原位采集系统对该区土壤剖面不同土层N2O、CO2浓度动态变化进行了为期1a的田间原位监测.共设3个处理：1979年以来规划的禁牧（UG79）、1999年以来规划的禁牧（UG99）和持续放牧（CG）小区.结果表明：土壤剖面N2O、CO2浓度具有明显的时空分布特征：①3个处理不同时期土壤剖面CO2平均浓度均表现为：生长期 > 冻融期 > 冻结期，且生长期CO2浓度要远大于冻融期和冻结期；UG79土壤剖面CO2浓度最高，CG最低；不同土层间CO2浓度有所差异，具体表现为UG79、UG99：20 cm≥50 cm≥35 cm≥10 cm≥5 cm；CG：50 cm≥35 cm≥20 cm≥10 cm≥5 cm；②土壤剖面N2O浓度时空变化特征则与CO2不同，UG79、UG99呈现出"单峰型"变化规律，CG为"双峰型"变化规律，即虽然CG在生长期N2O也有微弱的释放，但3个处理土壤剖面N2O浓度均在土壤冻融期内急剧增加，其中CG处理土壤剖面N2O平均浓度最高，与UG79、UG99差异显著（P<0.05）；不同土层土壤剖面N2O浓度表现为UG79：20 cm≥50 cm≥35 cm≥10 cm≥5 cm；CG：50 cm≥35 cm≥20 cm≥10 cm≥5 cm；UG99：35 cm≥50 cm≥20 cm≥10 cm≥5 cm.研究得出放牧可以使该区土壤剖面CO2浓度降低、N2O浓度升高，这为我国草原季节性冻土区温室气体的准确评估提供了重要的理论支持. |
| 英文摘要 |
| In order to evaluate the effect of grazing on the mechanism for greenhouse gas emissions in the seasonal frozen soils for a typical steppe in Inner Mongolia, variations of N2O and CO2 concentrations in different soil layers were monitored by an in situ gas collection system. Three conditions were selected:ungrazed since 1979 (UG79), ungrazed since 1999 (UG99), and continuously grazed (CG). The results showed that the profile soil N2O and CO2 concentrations demonstrated a significant spatio-temporal distribution. ① The average concentrations of CO2 in the soil profile of the three conditions were:CO2 in the growth period > in the freezing-thawing period > in the freezing period. The CO2 concentrations in the growing period were much higher than in the freezing-thawing period and freezing period. The CO2 concentration was the highest in the UG79, and the lowest was in the CG. The concentration of CO2 in different soil layers was ordered as 20 cm ≥ 50 cm ≥ 35 cm ≥ 10 cm ≥ 5 cm at the UG79 and UG99 sites, and 50 cm ≥ 35 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm at the CG site. ② The spatial and temporal variation of N2O concentration in the soil profile was different from that of CO2. While the UG79 and UG99 sites showed a "single peak type" change, the CG site had a "bimodal" pattern. The N2O concentration of the three conditions increased sharply during the soil freezing-thawing period, and the N2O was also released weakly during the growing season at the CG site (P<0.05). The average N2O concentration of the CG was significantly higher than that of UG79 and UG99 (P<0.05). The results show that the concentration of N2O in different soil layers was ordered as follows:UG79:20 cm ≥ 50 cm ≥ 35 cm ≥ 10 cm ≥ 5 cm; CG:50 cm ≥ 35 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm, and UG99:35 cm ≥ 50 cm ≥ 20 cm ≥ 10 cm ≥ 5 cm. The results concluded that grazing decreased the profiled soil CO2 concentration and increased N2O concentration, which provides a basis for the accurate estimation of greenhouse gas emissions in the seasonal frozen soil in grasslands. |
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