缓释尿素（原名涂层尿素）和长效碳酸氢铵是我国自行研制的两种长效氮肥，经在京郊大面积试用效果较好。长效氮肥之所以能够“长效”，原因在于其添加成分具有硝化抑制剂的作用，能够减少氮的损失，长效碳铵的添加物双氰铵（简称ＤＣＤ）还具有铵稳定剂的作用。从综合表现来看 Slow-release urea (formerly known as coated urea) and long-acting ammonium bicarbonate are two long-acting nitrogenous fertilizers developed by our country. The reason why long-acting nitrogen fertilizer can be “long-lasting” because of its role as a nitrification inhibitor added components, can reduce the loss of nitrogen, long-acting ammonium bicarbonate additive DCD also has the role of ammonium stabilizers . Judging from the overall performance