%0 Journal Article
%T Characteristics and factors of the N2O emission from the continuous cropping paddyfield in irrigation area of the Yellow River<br>黄河上游灌区连作稻田N2O排放特征及影响因素
%A ZHANG Hui
%A ZHANG Qingwen
%A YANG Zhengli
%A <br>张惠
%A 张晴雯
%A 杨正礼
%J 环境科学学报
%D 2012
%I 
%X Some nitrogen oxides in the atmosphere are increasing year by year due to the overuse or misuse of fertilizers in the upstream of the Yellow River. Field experiments were carried out in a continuous cropping paddyfield in the Ningxia Hui Autonomous Region in northwestern China. The static chamber-gas chromatograph method was used to measure the N2O emission from the paddyfield of the irrigation area in the Yellow River. Three field N treatments were conducted, including the conventional N application rate of 300 kg·hm-2 (N300), the optimized N application rate of 240 kg·hm-2 (N240) and no N fertilizer application plot (N0). The results showed that N2O emissions mainly occurred after the application of basal fertilizer or at the mid-to-late stages of rice growth. More N2O emissions were measured before rice planting and irrigation, and the N2O emission rate reached its maximum at 2~3 d after irrigation during the rice growing stage. The key factors affecting N2O emissions from the continuous rice-cropping field were N application rate, water-saving treatment, soil temperature and soil NO3--N content. Excessive application of N fertilizers in the irrigated paddyfield will significantly increase N2O emissions. However, optimization of N application can reduce N2O emissions from the paddy soil during the rice growing season (p<0.01). With the continuous yearly rice planting, the conventional high-level N fertilizer application significantly increased nitrate accumulation in 0~40 cm layer topsoil, and increased N2O emissions from the paddy soil. Based on statistical data, with the conventional irrigation practice and high nitrogen fertilizer of 300kg·hm-2, the total amount of N2O emissions from the paddyfields reached at 55.98×104 kg·a-1 in 2009 and 51.48×104 kg·a-1 in 2010 during the whole rice growing season. In the scales of 100a, the global warming potential (GWPs) was 16.02×107 kg·hm-2 in the irrigation area of Yellow River. Compared with N300 treatment, the cumulative N2O emissions in N240 treatments decreased by 11.16×104 kg·a-1. In the scales 100a, GWPs caused by N2O emissions in the paddy field decreased 3.30×107 kg CO2·hm-2, indicating GWPs of N2O emissions from the paddy field was immense in the Yellow River irrigation area.
%K irrigation area of the Yellow River
%K the continuous rice-cropping field
%K nitrogen application
%K N2O emission
%K emission factors<br>黄灌区
%K 连作稻田
%K 氮肥
%K N2O排放特征
%K 影响因素
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=3FF3ABA7486768130C3FF830376F43B398E0C97F0FF2DD53&cid=A7CA601309F5FED03C078BCE383971DC&jid=03A55E61A8750ACAC6AF81EF9E2AC838&aid=1D086AF23E396C1ECF7F888E63B0E4CC&yid=99E9153A83D4CB11&vid=9971A5E270697F23&iid=5D311CA918CA9A03&sid=25BD9D96DA3633C5&eid=E1E3BF53C3583450&journal_id=0253-2468&journal_name=环境科学学报&referenced_num=0&reference_num=50