【摘要】 美国是肥料生产和使用的大国。其氮肥主要品种是浓缩氨水和尿素 ,磷肥为磷酸二铵 ,钾肥为氯化钾。复混肥料占有重要地位。近 10年来 ,全国肥料年施用量趋于稳定。 4类大宗农作物的施肥量占了总施肥量的 90 %以上。确定肥料使用量 ,测土施肥仍为重要的手段。机械化施肥是美国肥料使用的特点。施肥对环境的影响已受到广泛重视。变化用量施肥技术有待推广更多还原

【Abstract】 USA is the largest fertilizer producer and consumer in the world. Anhydrous ammonia, urea, diammonium phosphate and potassium chloride are among the most important fertilizers in United State in addition to mixed or compound fertilizers. The total amounts of fertilizer applied each year has been stabilized for the past decade, among which, over 90% are applied on the four staple crops. Soil testing is the common method for fertilizer recommendation. Fertilizer application is mainly completed by mechanized applicator. The potential impact of fertilizer use on the environment has been drawn great concern. Variable rate technology in fertilizer application needs to be extended to practical use.更多还原