Urea is a nonionic fertilizer nitrogen material which has become of increasing importance in agricultural production. It is prepared by reacting anhydrous ammonia and carbon dioxide gas under very high pressure in the presence of a suitable catalyst.

• 尿素是一种非离子型氮肥，在农业生产上变得日益重要。它是在某种催化剂参与下，由无水氨和二氧化碳气体在高压条件下反应生成的。