Why is the proportion of water-soluble phosphorus in monoammonium and diammonium phosphates low relative to available phosphorus?
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Recently, it was found that in a batch of raw materials purchased by our company, the proportion of water-soluble phosphorus in monoammonium phosphate and diammonium phosphate is low relative to the effective phosphorus content. What is the reason for this? What about those with 2 fewer nutrients? Will using it have an impact on the effectiveness of fertilizers?
I didn’t give you enough of that ingredient. You can check them with the industrial and commercial authorities.
The main reason for the low level of water-soluble phosphorus is an issue with the raw materials; specifically, the high content of metal impurities in the minerals leads to excessive binding of phosphorus during the neutralization process, resulting in phosphorus-containing compounds with poor water solubility and thus a low level of water-soluble phosphorus. This is also an inevitable consequence of the increasingly poor quality of phosphate rocks being used for the production of phosphatic ammonium fertilizers; it is not something our manufacturing enterprises intend to do. Of course, in the production process, efforts should be made through ore blending and other methods to avoid such issues and ensure that the required standards are met.
Fertilizers contain recognized available phosphorus; both the nutrients and their pricing are based on this available phosphorus. Available phosphorus, abbreviated as A-P, is also known as rapidly available phosphorus, and it refers to the portion of phosphorus in the soil that can be absorbed by plants. This includes all water-soluble phosphorus, some adsorbed phosphorus, and organic phosphorus; in some soils, it also includes certain precipitated forms of phosphorus； Of course, the amount of water-soluble phosphorus indicates the solubility rate; the higher it is, the easier it is for the phosphorus to dissolve in water and be absorbed by crops
It is very important as it directly affects the effectiveness of fertilizer application
Supporting what was said on the 3rd floor: it is normal for the water-soluble phosphorus level to be lower than that of the available phosphorus; only industrial-grade products are more similar in this regard. With the increase in impurities from mineral sources in wet-process production, not only do the costs rise, but the acidity also decreases. In the slurry production method using monoammonium phosphate, the amount of water-insoluble substances also increases. Among these impurities are cationic substances that can exist as soluble phosphorus fertilizers, as well as some insoluble phosphorus. As long as the amount of available phosphorus is sufficient, the efficacy of the fertilizer should remain the same; the only difference lies in the speed at which plants absorb it. An increase in water-insoluble substances is normal. As for any impact, it depends on how the fertilizer is used – for example, in drip irrigation, too high a concentration will definitely cause blockages in the drippers. In the case of ordinary compound fertilizers, the impact is likely to be minimal
It’s probably because of the high magnesium content; the fertilizer sold to you by others doesn’t meet the required nutrient standards
Effective phosphorus refers to both soluble phosphorus and phosphorus that can be absorbed quickly; this does not include phosphorus that is lost due to fertilization practices. If the effective phosphorus content in the phosphate fertilizer you purchase is low, it means you have bought a mixture of phosphate fertilizer and phosphate rock. The company that sells you this fertilizer is extremely irresponsible – substandard products must not be released onto the market
Currently, the quality of phosphate rocks has declined, resulting in a decrease in the water-soluble phosphorus content in DAP and MAP. Effective phosphorus equals water-soluble phosphorus plus citrate-soluble phosphorus; the water-soluble phosphorus level is certainly lower than that of effective phosphorus. The percentage of water-soluble phosphorus in DAP ranges from 80% to 88%
Supporting what was said on the 3rd floor: it is normal for the water-soluble phosphorus level to be lower than that of available phosphorus; only industrial-grade products are more similar in this regard. With the increase in impurities from mineral sources in current wet-process production, not only do the costs rise, but the quality of the acid also deteriorates. Of course, this is also related to the control of the production process
I recommend reading two articles: 1. http://wenku.baidu.com/view/f65b9cc24028915f804dc264.html——The significance of determining water-soluble phosphorus in compound fertilizers. 2. http://wenku.baidu.com/view/663f442ded630b1c59eeb5d0.html--The influence of neutralization reaction time on the water-soluble phosphorus in phosphate ammonium products.