Adviento-Borbe Maria Arlene, Pittelkow Cameron M, Anders Merle, van Kessel Chris, Hill James E, McClung Anna M, Six Johan, Linquist Bruce A
J Environ Qual. 2013 Nov;42(6):1623-34. doi: 10.2134/jeq2013.05.0167.
Drill seeded rice ( L.) is the dominant rice cultivation practice in the United States. Although drill seeded systems can lead to significant CH and NO 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 = GWP Mg grain) is achieved. Each growing season, urea was applied at rates ranging from 0 to 224 kg N ha before the permanent flood. Emissions of CH and NO were measured daily to weekly during growing seasons and fallow periods. Annual CH emissions ranged from 9.3 to 193 kg CH-C ha yr across sites, and annual NO emissions averaged 1.3 kg NO-N ha yr. Relative to NO emissions, CH 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 CH emissions but contributing to greater NO 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 ranged from 130 to 686 kg CO eq Mg season across sites and years. Fertilizer N rate had no significant effect on GWP; therefore, achieving the highest productivity is not at the cost of higher GWP.
条播水稻(L.)是美国主要的水稻种植方式。尽管条播系统由于土壤的厌氧和好氧条件会导致大量的CH和NO排放,但高产管理措施,特别是氮肥管理与全球变暖总潜能(GWP)之间的关系仍不明确。我们在加利福尼亚州和阿肯色州进行了三项田间试验,以检验通过氮肥管理优化谷物产量可实现最低产量规模全球变暖潜能(GWP = GWP/ Mg谷物)这一假设。在每个生长季,在永久性淹水前以0至224 kg N/ha的用量施用尿素。在生长季和休耕期,每天至每周测量CH和NO的排放量。各试验点的年CH排放量在9.3至193 kg CH-C/ha·yr之间,年NO排放量平均为1.3 kg NO-N/ha·yr。相对于NO排放,CH在生长季(82%)和全年(68%)的GWP中占主导地位。氮肥用量对温室气体通量的影响仅限于生长季,氮肥用量增加对CH排放影响不大,但在非淹水期会导致更多的NO排放。休耕期对各试验点各年份年GWP的贡献在7%至39%之间。这一发现表明在年度排放估算中需要纳入休耕期的测量数据。各试验点各年份生长季GWP在130至686 kg CO₂eq/Mg季之间。氮肥用量对GWP没有显著影响;因此,实现最高产量并非以更高的GWP为代价。