What are the application characteristics and precautions of calcium magnesium phosphate fertilizer?
Calcium magnesium phosphate fertilizer is insoluble in water, non-toxic, non-corrosive, non-hygroscopic, and does not cake, and is a chemically alkaline fertilizer. It is widely suitable for various crops and phosphorus-deficient acidic soils, and is especially suitable for the acidic red soils of the south where calcium and magnesium leaching is relatively severe.
Application characteristics
1. It is most suitable for deep application as a base fertilizer. After calcium magnesium phosphate fertilizer is applied to the soil, the phosphorus in it can only be dissolved by weak acids, and it must undergo a certain transformation process before it can be utilized by crops, so its fertilizer effect is relatively slow and it belongs to the slow-release category of fertilizers. Generally, it should be combined with deep plowing, applying the fertilizer evenly into the soil and mixing it with the soil layer, so as to facilitate its dissolution by soil acids and to benefit its absorption by crops.
2. In paddy fields in the south, it can be used to dip rice seedling roots. The dosage is about 10 kg per mu, it causes no harm to the seedlings, and the effect is also relatively good.
3. Mix and compost it with more than 10 times its amount of high-quality organic fertilizer for more than 1 month; the composted fertilizer can be used as a base fertilizer, seed fertilizer, or to dip rice seedling roots.
Precautions
1. Calcium magnesium phosphate fertilizer has a relatively good effect when applied in combination with superphosphate and nitrogen fertilizer, but it cannot be applied mixed with them.
2. Calcium magnesium phosphate fertilizer usually cannot be applied mixed with acidic fertilizers, otherwise it will reduce the fertilizer effect.
3. The dosage of calcium magnesium phosphate fertilizer must be appropriate; generally the dosage per mu should be controlled between 15 and 25 kg. If calcium magnesium phosphate fertilizer is applied excessively, not only will its fertilizer effect not increase progressively, but the problem of diminishing returns will also appear. Usually, when 35 to 40 kg of calcium magnesium phosphate fertilizer is applied per mu, it can be applied every other year.
4. Calcium magnesium phosphate fertilizer is most suitable for crops with a strong ability to absorb citrate-soluble phosphorus, such as rapeseed, radish, leguminous green manure, leguminous crops, and cucurbit crops.