However, when the available P was excessive in soil, the input of organic manure had to be quantified according to the input of P from organic manure.

• 有机肥施用于新菜田应考虑“以氮定量”的原则，而施用于土壤有效磷过量累积的老菜田，应采取“以磷定量”原则，来控制有机肥中的磷素投入；