Estimation of Nitrous Oxide Emissions from US Grasslands
Estimation of Nitrous Oxide Emissions from US Grasslands
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DOI：
10.1007/s002679910013
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发表时间：
2000-02
影响因子：
3.5
通讯作者：
D. Mummey;Jeffrey L. Smith;G. Bluhm
中科院分区：
文献类型：
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作者：
D. Mummey;Jeffrey L. Smith;G. Bluhm
2 O）排放量从温带草原是很难量化，可能是一个重要的一部分，大气N2 O预算。在这项研究中，N2 O的排放量模拟了1052个草地网站在美国使用的NGAS模型的Parton和其他人（1996年）结合有机物分解模型。使用从国家资源清单（NRI）数据库获得的土壤和土地利用数据以及从NASA获得的天气数据计算了每个地点的N2 O通量。根据温度和湿度等温线对估计数进行了区域化。每个区域的N2 O年排放量是基于每个区域的草地面积和该区域NRI草地站点的年N2 O通量的平均估计值。区域通量范围为0.18至1.02千克N2 O-N/公顷/年，所有区域的平均通量为0.28千克N2 O-N/公顷/年。尽管西部地区的通量相对较低，但这些地区由于其大面积的草原面积，对总排放量的贡献最大。美国草地N2 O总排放量估计约为67千兆克N2 O/年。据估计，大平原各州的排放量平均为0.24千克N2 O/公顷/年，这些州拥有美国最大的天然草地。使用温带大平原的年通量估计，我们估计，全球温带草原可能产生0.27 Tg N2 O N/年。尽管我们对全球温带草原N2 O排放量的估计低于其他主要温带和热带生物群落的估计，但我们的研究结果表明，温带草原是美国和全球大气N2 O预算的重要组成部分。这项研究表明，区域N2 O通量估计模型的实用性，虽然需要额外的数据，精心设计的实地研究，以进一步验证模型的结果。
2O) emissions from temperate grasslands are poorly quantified and may be an important part of the atmospheric N2O budget. In this study N2O emissions were simulated for 1052 grassland sites in the United States using the NGAS model of Parton and others (1996) coupled with an organic matter decomposition model. N2O flux was calculated for each site using soil and land use data obtained from the National Resource Inventory (NRI) database and weather data obtained from NASA. The estimates were regionalized based upon temperature and moisture isotherms. Annual N2O emissions for each region were based on the grassland area of each region and the mean estimated annual N2O flux from NRI grassland sites in the region. The regional fluxes ranged from 0.18 to 1.02 kg N2O N/ha/yr with the mean flux for all regions being 0.28 kg N2O N/ha/yr. Even though fluxes from the western regions were relatively low, these regions made the largest contribution to total emissions due to their large grassland area. Total US grassland N2O emissions were estimated to be about 67 Gg N2O N/yr. Emissions from the Great Plains states, which contain the largest expanse of natural grassland in the United States, were estimated to average 0.24 kg N2O N/ha/yr. Using the annual flux estimate for the temperate Great Plains, we estimate that temperate grasslands worldwide may potentially produce 0.27 Tg N2O N/yr. Even though our estimate for global temperate grassland N2O emissions is less than published estimates for other major temperate and tropical biomes, our results indicate that temperate grasslands are a significant part of both United States and global atmospheric N2O budgets. This study demonstrates the utility of models for regional N2O flux estimation although additional data from carefully designed field studies is needed to further validate model results.