Optimal Fertilizer Nitrogen Rates and Yield-Scaled Global Warming Potential in Drill Seeded Rice
Optimal Fertilizer Nitrogen Rates and Yield-Scaled Global Warming Potential in Drill Seeded Rice
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DOI：
10.2134/jeq2013.05.0167
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发表时间：
2013-11-01
影响因子：
2.4
通讯作者：
Linquist, Bruce A.
中科院分区：
文献类型：
--
作者：
Adviento-Borbe, Maria Arlene;Pittelkow, Cameron M.;Linquist, Bruce A.
钻播水稻（Oryza sativa L.）是美国主要的水稻种植方式。尽管由于厌氧和好氧土壤条件，钻播系统可导致大量CH4和N2O排放，但高产管理措施，特别是氮肥管理与总全球变暖潜能值（GWP）之间的关系尚不清楚。我们在加利福尼亚州和阿肯色州进行了三个田间试验，以验证通过氮管理优化粮食产量的假设，即实现最低产量规模的全球变暖潜能值（GWP(Y) = GWP Mg-1谷物）。每个生长季节，在永久淹水前，尿素的施用量为0 ~ 224 kg N ha（-1）。在生长季和休耕期，每天至每周测量CH4和N2O的排放量。各站点年CH4排放量在9.3 ~ 193 kg CH4- c ha（-1）年（-1）之间，年N2O排放量平均为1.3 kg N2O- n ha（-1）年（-1）。相对于N2O排放，CH4在生长期（82%）和年（68%）GWP中占主导地位。氮肥施量对温室气体通量的影响仅限于生长季节，氮肥施量的增加对CH4排放影响不大，但在非淹水期增加了N2O排放。休耕期对年全球变暖潜能值的贡献在7 - 39%之间。这一发现说明有必要在年度排放估算中包括休耕期的测量。不同地点和年份的生长期GWP(Y)在130 ~ 686 kg CO2当量Mg-1之间。施氮量对GWP(Y)无显著影响；因此，实现最高生产率并不是以更高的GWP(Y)为代价的。
Drill seeded rice (Oryza sativa L.) is the dominant rice cultivation practice in the United States. Although drill seeded systems can lead to significant CH4 and N2O emissions due to anaerobic and aerobic soil conditions, the relationship between high-yielding management practices, particularly fertilizer N management, and total global warming potential (GWP) remains unclear. We conducted three field experiments in California and Arkansas to test the hypothesis that by optimizing grain yield through N management, the lowest yield-scaled global warming potential (GWP(Y) = GWP Mg-1 grain) is achieved. Each growing season, urea was applied at rates ranging from 0 to 224 kg N ha(-1) before the permanent flood. Emissions of CH4 and N2O were measured daily to weekly during growing seasons and fallow periods. Annual CH4 emissions ranged from 9.3 to 193 kg CH4-C ha(-1) yr(-1) across sites, and annual N2O emissions averaged 1.3 kg N2O-N ha(-1) yr(-1). Relative to N2O emissions, CH4 dominated growing season (82%) and annual (68%) GWP. The impacts of fertilizer N rates on GHG fluxes were confined to the growing season, with increasing N rate having little effect on CH4 emissions but contributing to greater N2O emissions during nonflooded periods. The fallow period contributed between 7 and 39% of annual GWP across sites years. This finding illustrates the need to include fallow period measurements in annual emissions estimates. Growing season GWP(Y) ranged from 130 to 686 kg CO2 eq Mg-1 season(-1) across sites and years. Fertilizer N rate had no significant effect on GWP(Y); therefore, achieving the highest productivity is not at the cost of higher GWP(Y).