Measurement of Net Global Warming Potential in Three Agroecosystems
Measurement of Net Global Warming Potential in Three Agroecosystems
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DOI：
10.1007/s10705-004-7356-0
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发表时间：
2005-05
影响因子：
3.1
通讯作者：
A. Mosier;A. Halvorson;Gary A. Peterson;G. Robertson;L. Sherrod
中科院分区：
文献类型：
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作者：
A. Mosier;A. Halvorson;Gary A. Peterson;G. Robertson;L. Sherrod
在评估粮食和纤维生产系统对地球大气成分和“温室”效应的影响时，需要考虑整套生物温室气体——二氧化碳 (CO2)、甲烷 (CH4) 和一氧化二氮 (N2O)。将大气中的二氧化碳储存到土壤中的稳定有机碳库中可以封存二氧化碳，而常见的作物生产实践可以产生二氧化碳，产生氧化亚氮，并减少大气中甲烷的土壤汇。这些气体净交换之间的总体平衡构成了作物生产系统的净全球变暖潜势（GWP）。来自长期研究的痕量气体通量和土壤有机碳 (SOC) 存储数据、密歇根州的一个雨养地点对比传统耕作 (CT) 和免耕 (NT) 耕作、科罗拉多州东北部的一个雨养地点比较 NT 的耕作系统以及科罗拉多州的一个灌溉地点比较耕作和轮作，用于估算作物生产系统的净 GWP。一氧化二氮排放量占两个雨养地点 GWP 的 40-44%，占灌溉系统 GWP 的 16-33%。用于灌溉的能源是灌溉系统中主要的全球升温潜能值来源。系统是 CO2 的汇还是源，即净 GWP，由所有站点的 SOC 存储率控制。两种雨养连作系统表面 7.5 厘米处的 SOC 累积量约为 1100 kg CO2 当量 ha−1y−1。灌溉系统的碳累积率大约高出三倍。雨养系统已在北领地使用超过 10 年，而灌溉系统在本研究开始前 3 年已转换为北领地。灌溉系统中的碳累积率是否会随着时间的推移而下降，或者在转换为 NT 后，N2O 排放率是否会随着时间的推移而下降或增加，仍有待观察。
When appraising the impact of food and fiber production systems on the composition of the Earth's atmosphere and the ‘greenhouse’ effect, the entire suite of biogenic greenhouse gases – carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) – needs to be considered. Storage of atmospheric CO2into stable organic carbon pools in the soil can sequester CO2while common crop production practices can produce CO2, generate N2O, and decrease the soil sink for atmospheric CH4. The overall balance between the net exchange of these gases constitutes the net global warming potential (GWP) of a crop production system. Trace gas flux and soil organic carbon (SOC) storage data from long-term studies, a rainfed site in Michigan that contrasts conventional tillage (CT) and no-till (NT) cropping, a rainfed site in northeastern Colorado that compares cropping systems in NT, and an irrigated site in Colorado that compares tillage and crop rotations, are used to estimate net GWP from crop production systems. Nitrous oxide emissions comprised 40–44% of the GWP from both rain-fed sites and contributed 16–33% of GWP in the irrigated system. The energy used for irrigation was the dominant GWP source in the irrigated system. Whether a system is a sink or source of CO2, i.e. net GWP, was controlled by the rate of SOC storage in all sites. SOC accumulation in the surface 7.5 cm of both rainfed continuous cropping systems was approximately 1100 kg CO2equivalents ha−1y−1. Carbon accrual rates were about three times higher in the irrigated system. The rainfed systems had been in NT for >10 years while the irrigated system had been converted to NT 3 years before the start of this study. It remains to be seen if the C accrual rates decline with time in the irrigated system or if N2O emission rates decline or increase with time after conversion to NT.