Fertilizer

The purpose of the present invention is to provide a fertilizer capable of using fertilizer efficiency components for crops for a long period of time. The fertilizer according to the present inventioncomprises a carrier that carries phosphorus and iron, the ratio of citric acid-soluble phosphoric acid to total phosphoric acid in the fertilizer being 18% or more, and the ratio of water-soluble phosphoric acid to total phosphoric acid in the carrier being 1% or less. The carrier may be a porous body. The porous body may contain a carbide. The total phosphoric acid, the citric acid-soluble phosphoric acid, and the water-soluble phosphoric acid may be determined by ammonium vanadate absorbance spectrometry. 本发明的目的在于提供一种能够长时间利用对于农作物的肥效成分的肥料。本发明的肥料包含承载磷和铁的载体，上述肥料中的枸溶性磷酸相对于总磷酸的比率为18％以上，且上述载体中的水溶性磷酸相对于总磷酸的比率为1％以下。上述载体可以是多孔质体。上述多孔质体可以包含碳化物。上述总磷酸、上述枸溶性磷酸以及上述水溶性磷酸可以通过钒钼酸铵吸光光度法而求出。