What phosphate fertilizers are there? A comprehensive answer on common types of phosphate fertilizers
Today a farmer called in to ask: there are many kinds of phosphate fertilizers on the market, and each product dealer describes them differently, so how should one choose the right phosphate fertilizer? There are quite a few types of phosphate fertilizers, and three are introduced first below: 1. Superphosphate: the main component has the molecular formula Ca(H2PO4)2·H2O, and it contains 14-20% available phosphorus (P2O5)...
Today a farmer called in to ask: there are many kinds of phosphate fertilizers on the market, and each product dealer describes them differently, so how should one choose the right phosphate fertilizer?There are quite a few types of phosphate fertilizers, and three are introduced first below:
1. Superphosphate:
The main component has the molecular formula Ca(H2PO4)2·H2O, and it contains 14-20% available phosphorus (P2O5). The color of the product is related to the phosphate rock raw material, and it is generally a gray or pale yellow powder. The secondary component is anhydrous calcium sulfate, accounting for about 50% of the total, and it contains 3-5% free acid and secondary compounds such as iron phosphate and aluminum phosphate. It is an acidic fertilizer with a certain degree of hygroscopicity and caking. During storage, there is a degradation effect on phosphorus, and it is generally not suitable to store it for more than one and a half years.
Superphosphate is suitable for various soils and crops, and can be used as a base fertilizer, a topdressing fertilizer and for foliar spraying.
2. Triple superphosphate:
Triple superphosphate is made by decomposing phosphate rock with phosphoric acid, and it is the phosphate fertilizer with the highest phosphorus content. Its main component is the same as that of ordinary superphosphate, and it contains 42-50% available phosphorus (P2O5) and 4-8% free acid, and contains no gypsum or very little gypsum.
Since its phosphorus content is about three times that of superphosphate, it is therefore called triple superphosphate or concentrated superphosphate. Triple superphosphate is more stable in nature than superphosphate and is easily soluble in water.
3. Calcium magnesium phosphate:
The main component of calcium magnesium phosphate is tricalcium phosphate Ca3(PO4)2, and it contains 14-20% phosphorus (P2O5), while also containing calcium oxide (about 40%), silicon oxide (about 20%) and magnesium oxide, etc. It belongs to citrate-soluble phosphate fertilizers. The product appearance is a grayish-white, grayish-green or grayish-black powder. It is slightly alkaline, does not absorb moisture or cake, and is non-corrosive.
Calcium magnesium phosphate is suitable for various crops, but the effect is better when used on calcium-loving leguminous crops and silicon-loving cereal crops; the effect of application on acidic soil is better than on calcareous soil; it is suitable for use as a base fertilizer, and before application it is best to mix it with high-quality organic fertilizer and compost it for 20-30 days.
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