一、根据作物需肥特性。作物因种类、品种、生长发育时期的不同,对养分的类型及数量有着不同的需求。同一种作物在不同生长时期,对各种养分的需求量不同。在营养生长期,不要过多施用氮肥。麦、稻、禾谷类需氮多;豆科、花生、油菜因与其共生的根瘤菌,可以固定空气中的氮素,主要 First, according to the characteristics of crops to be fat. Due to the different types of crops, varieties, growth and development of different periods, the types and quantities of nutrients have different needs. The same crops in different growth stages, the demand for a variety of nutrients. During vegetative growth, do not overuse nitrogen fertilizer. Wheat, rice, cereals and more nitrogen required; Leguminosae, peanuts, rape rhizobia due to its symbiosis, you can fix the nitrogen in the air, the main