Mixed fertilizer typically refers to a fertilizer containing two or more of the elements of nitrogen, phosphorus and potassium (NPK) which are essential for promoting plant growth and high crop yields. They are obtained by thoroughly mixing the ingredients either manually or mechanically.
Mixed fertilizer reactions
NH3 +H3PO4 =NH4H2PO4
NH4H2PO4 +NH3 = (NH4)2HPO4
DAP+UREA+POTASH+FILLER = MIXED FERTILISER
30-30-40 means 30% N2, 30% P and 40% K