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-thawingtypical steppesoil profilegreenhouse gasgrazing

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

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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