Long‐Term Grazing Alters Soil Trace Gas Fluxes from Grasslands in the Foothills of the Rocky Mountains, Canada
Long‐Term Grazing Alters Soil Trace Gas Fluxes from Grasslands in the Foothills of the Rocky Mountains, Canada
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DOI：
10.1002/ldr.2664
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发表时间：
2018-02
影响因子：
4.7
通讯作者：
Xinlei Gao;B. Thomas;R. Beck;D. Thompson;Mengli Zhao;W. Willms;X. Hao
中科院分区：
文献类型：
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作者：
Xinlei Gao;B. Thomas;R. Beck;D. Thompson;Mengli Zhao;W. Willms;X. Hao
长期放牧可能会使草原土壤退化，但土壤CO2，CH 4和N2 O通量对长期放牧的反应知之甚少。因此，我们量化了土壤CO2，CH 4和N2 O通量，以响应四个水平（无，轻，重，非常重）的长期（>65年）放牧牛在加拿大落基山脉山麓的粗糙的牛毛草草地上的三个放牧季节。放牧草地土壤比非放牧土壤排放的CO2多37%至51%。放牧草地土壤是CH 4的小汇和N2 O的小源，其累积通量受放牧率×年份交互作用的影响显著，说明放牧效应受环境条件的影响。土壤CH 4吸收量与土壤湿度呈负相关（r =-0.59）。2013年放牧季节的降水量比平均水平高出约41%，与非放牧土壤相比，放牧显著降低了CH 4吸收量31%至38%。N2 O的排放量为122至179%以上，在雨季，不受放牧在正常的降水季节和72%，轻放牧比没有在旱季。由于气候条件、土壤性质和放牧强度之间的相互作用，放牧草地土壤中痕量气体通量的时空预测是困难的。然而，长期放牧增加了土壤CO2通量，而放牧对CH 4吸收的影响依赖于降水，土壤N2 O通量响应于放牧强度和降水。© 2016 Her Majesty the Queen in Right of Canada.《土地退化与发展》，John Wiley & Sons Ltd.出版
Long‐term cattle grazing may degrade grassland soils, but how soil CO2, CH4 and N2O fluxes respond to long‐term cattle grazing is poorly understood. Therefore, we quantified soil CO2, CH4 and N2O fluxes in response to four levels (none, light, heavy, very heavy) of long‐term (>65 years) cattle grazing on a rough fescue grassland in the foothills of the Rocky Mountains, Canada over three grazing seasons. The grazed grassland soils emitted 37 to 51% more CO2 than non‐grazed soils. Grazed grassland soils were small CH4 sinks and small N2O sources each season, and their cumulative fluxes were significantly affected by a cattle stocking rate × year interaction, indicating the grazing effect was influenced by environmental conditions. Soil CH4 uptake was negatively correlated with soil moisture (r = −0·59). The 2013 grazing season had about 41% greater precipitation than average and grazing significantly decreased CH4 uptake 31 to 38% compared with non‐grazed soils. The N2O emissions were 122 to 179% greater with heavy and very heavy grazing than none in the wet season, unaffected by grazing in the normal precipitation season and 72% lower with light grazing than none in the dry season. Predicting trace gas fluxes from grazed grassland soils across space and time is difficult because of interactions among weather conditions, edaphic properties and grazing intensity. However, long‐term cattle grazing increased soil CO2 fluxes, while the grazing effect on CH4 uptake depended on precipitation and the soil N2O flux responded as a function of grazing intensity and precipitation. © 2016 Her Majesty the Queen in Right of Canada. Land Degradation & Development Published by John Wiley & Sons Ltd.