The main producing area of calcium magnesium phosphate fertilizer is in China. Due to its wide source of raw materials and simple production process, the production of phosphate rock in southern China has developed rapidly in recent years. The appearance of the fertilizer is gray, black green or brown glassy fine powder, and the composition is relatively complicated, mainly Ca3(PO4)2, and other components such as P2O5, CaO, MgO, SiO2 and CaMg. Due to different origins, the product specifications vary greatly. Generally, the P2O5 content is between 14% and 20%, the CaO content is between 25% and 30%, the MgO content is between 10% and 15%, and the SiO2 content is 25%. 40%. It can be seen that calcium magnesium phosphate fertilizer is a multi-fertilizer mainly containing phosphorus and containing calcium, magnesium and silicon. Calcium magnesium phosphate fertilizer is insoluble in water, non-toxic, non-corrosive, non-hygroscopic, non-caking, chemically alkaline fertilizer. It is widely used in various crops and acidic soils deficient in phosphorus, especially suitable for acid red loam where calcium and magnesium are leached in the south. The specific use characteristics are as follows:
(1) It is most suitable for deep application of base fertilizer. After the calcium magnesium phosphate fertilizer is applied to the soil, the phosphorus can only be dissolved by the weak acid, and after a certain transformation process, it can be used by the crop, so the fertilizer efficiency is slow, and it is a slow-acting fertilizer. Generally, it should be combined with deep tillage, and the fertilizer should be evenly applied to the soil to mix it with the soil layer to facilitate the dissolution of the soil acid and facilitate the absorption of the crop.
(2) Southern paddy fields can be used to pick up roots. The dosage per acre is about 10 kg, which has no harm to the seedlings and the effect is better.
(3) Mixing with more than 10 times of high-quality organic fertilizer for more than 1 month, the good fertilizer can be used as base fertilizer, seed fertilizer, and can also be used to digest the root.
In the use of calcium magnesium phosphate fertilizer, the following aspects should be noted:
(1) Calcium, magnesium and phosphate fertilizers are better combined with calcium and nitrogen fertilizers, but they cannot be mixed with them.
(2) Calcium, magnesium and phosphate fertilizers can usually not be mixed with acidic fertilizers, otherwise the effect of fertilizers will be reduced.
(3) The dosage of calcium magnesium phosphate should be appropriate, generally the dosage per acre should be controlled at 15~25.
Between kilograms. Excessive application of calcium magnesium phosphate fertilizer will not only increase the fertilizer efficiency but also cause the problem of diminishing returns. Usually, when applying calcium and magnesium phosphate in 35 to 40 kg, it can be applied every other year.
(4) Calcium, magnesium and phosphorus fertilizers are most suitable for crops with strong absorption capacity of lysible phosphorus, such as rapeseed, radish, legume green manure, legume crops and melons.
