地表撒施尿素和碳酸氢铵尿素含氮量虽高,但施入土壤后要转化成铵态氮才能被农作物吸收利用。同时,尿素在转化时呈分子状态,不被土壤吸附,易随水土流失,使作物难以利用。尿素作追肥,应开沟条施并盖土。作叶面肥喷施,应掌握好施用浓度,喷施小麦、水稻、棉花、玉米,浓度以0.8%~1.0%为宜,蔬菜以0.3%~0.5%为佳。碳 Surface application of urea and ammonium bicarbonate Although high nitrogen content of urea, but into the soil after conversion to ammonium nitrogen can be absorbed by crops. At the same time, urea is transformed into a molecular state, not adsorbed by the soil, easy to soil erosion, making the crop difficult to use. Urea for top dressing, should be trenched facilities and cover the soil. For foliar application, should be well applied concentration, spraying wheat, rice, cotton, corn, the concentration of 0.8% to 1.0% is appropriate, vegetables to 0.3% to 0.5% better. carbon