摘要
采用田间试验研究了番茄地施用化学氮肥后的氨挥发、反硝化损失和N2O排放及其影响因素。氨挥发采用通气密闭室法测定，反硝化损失（N2＋N2O）采用乙炔抑制-土柱培养法测定，不加乙炔测定N2O排放。结果表明，番茄生长期间全部处理均未检测到氨挥发，其原因是土表氨分压低于检测灵敏度，较低的氨分压是由于表层土壤的铵态氮浓度和pH都不高所致。在番茄生长期间，对照区即来自有机肥和土壤本身的反硝化损失和N2O℃排放量相当高，反硝化损失总量高达N29．6kghm^-2，N2O排放量为N7．76kghm^-2。施用化学氮肥显著增加了反硝化损失和N2O排放，3个施用化学氮肥处理的反硝化损失变化在N40．8～46．1kghm^-2之间，占施入化肥氮量的5．50％～6．01％；N2O排放量为N13．6～17．6kghm^-2，占施入化肥氮量的2．62％～4．92％；与尿素相比，包衣尿素未能显著减低反硝化损失和N2O排放。施用尿素的处理在每次追肥后，耕层土壤均会出现NO3^--N高峰，继之的反硝化和N2O排放高峰。反硝化速率与土壤含水量呈极显著正相关。总的看来，番茄生长期间没有氨挥发，而硝化反硝化是氮素损失的重要途径之一。
A field experiment was conducted to investigate gaseous losses from N fertilizers applied to a tomato field and affecting factors. Ammonia volatilization was measured by the enclosure chamber method. Denitrification loss （N2 ＋ N2O） was measured by the acetylene inhibition-intact soil core technique, and N2Oemission was also measured in the absence of acetylene. Results show that ammonia volatilization was not detected in all the treatments during the tomato growing season. It was presumed that ammonia partial pressures on the surface soil were lower than the detection limit of the method, as a result of the low ammonical N concentration and low pH in the surface soil. During the tomato growing season, in the CK treatment denitrification loss and N2O emission were relatively high, which amounted to 29.6 kg hm^-2 and 7.76 kg hm^-2, respectively. Application of N fertilizer significantly increased denitrification loss up to the range of N 40.8 - 46.1 kg hm^-2, or 5.50% - 6.01% of the applied N; and N2O emission up to the range of N 13.6 - 17.6 kg hm^-2, or 2.62% - 4.92% of the applied N in the three fertilized treatments. Application of polymer coated urea didn＇ t show any significant effect on reducing denitrification loss and N2O emission in comparison with urea. In the two urea treatments soil nitrate peaks were observed after each topdressing event, and subsequent flux peaks of denitrification loss and N2O emission were found. There was a significant positive correlation between denitrification fluxes and water-filled pore space （WFPS） . It is concluded that ammonia volatilization is negligible, whereas nitrification-denitrification is an important pathway of N losses during the tomato growing season.
出处
《土壤学报》
CAS
CSCD
北大核心
2006年第1期62-68,共7页
Acta Pedologica Sinica
基金
国家自然科学基金项目(40171048)资助
关键词
氨挥发
反硝化损失
N2O排放
包衣尿素
番茄
Ammonia volatilization
Denitrification loss
N2O emission
Polymer coated urea
Tomato
