Urea is the first synthetic organic compounds, widely exists in nature, such as fresh meat contains urea 0.4%. Urea production accounts for about 40% of the total nitrogen fertilizer production in China, is second only to producyion of one of the main variety of nitrogen fertilizer. Formula is urea CO (NH2) 2, because contain the substance in human urine, so the name of urea. Urea nitrogen (N) 46%, the highest nitrogen content in solid nitrogen. Industry with liquid ammonia and carbon dioxide as raw material, the direct synthesis of urea under high temperature and high pressure conditions, the chemical reaction is as follows. 2 nh3 - NH2COONH4 - CO (NH2) 2 + CO2 + N2O urea soluble in water, 100 ml water in 20 ℃ can dissolve 105 grams, aqueous solution was neutral reaction. There are two kinds of urea product. Urea with a white needle crystal or prismatic crystal shape, moisture absorption is strong. Granular urea translucent particles for particle size of 1 ~ 2 mm, smooth appearance, hygroscopicity have markedly improved, is helpful to save. Urea can apply to basic fertilizer and fertilizer at the same time. Urea is physiological neutral fertilizer in the soil