尿素是我国主要的氮肥品种,占氮肥总量的65%左右。但因其活性强,损失途径多,除被作物吸收和土壤固持外,相当部分氮素通过氨挥发、反硝化、径流和淋溶等途径损失。我国大田作物氮肥当季平均利用率仅在30%左右,每年损失的尿素达2000万吨(商品量),直接经济损失达500多亿元,不仅造成能源与资源的巨大浪费,而且造成地表水富营养化、地下水和蔬菜中硝酸盐含量超标以及氮氧化物等温室气体排放 Urea is China’s main nitrogenous fertilizer species, accounting for about 65% of the total nitrogen fertilizer. However, due to its high activity and loss pathways, a considerable part of nitrogen is lost through ammonia volatilization, denitrification, runoff and leaching except by crop uptake and soil retention. The average utilization rate of field crops nitrogenous fertilizer is only about 30% in our country. The annual loss of urea reaches 20 million tons (commodity amount) and the direct economic loss reaches more than 50 billion yuan, which not only causes huge waste of energy and resources but also causes surface water Eutrophication, excessive nitrate content in groundwater and vegetables and greenhouse gas emissions such as nitrogen oxides