Urea is a high concentration of nitrogen, is a neutral fertilizer available, can also be used to produce a variety of compound fertilizers. In the soil without leaving any harmful substances, long-term application no adverse effects. Livestock can be used as ruminant feed. But in the granulation temperature is too high will produce a small amount of biuret, also known biuret, crop inhibited. China provides fertilizer urea biuret content should be less than 0.5%. When biuret content exceeds 1%, we can not do kind of fertilizer, Miaofei and fertilizer, urea content of the other application period should not be too much or too concentrated. Urea is an organic nitrogen fertilizer, through soil urease, hydrolysis into ammonium carbonate or bicarbonate after, in order to be absorbed by crops. Thus, urea should be administered 4 to 8 days before the crop needs the fertilizer. Urea suitable for use as basal and top dressing, sometimes used as a kind of fat. Before the conversion of urea molecular state, it can not be adsorbed soil, should prevent water loss with; ammonia formed after transformation also volatile, so have deep application of urea casing