(How is the effect compared to organic fertilizer)
Phosphate ore powder is made by directly crushing phosphorus ore. Its main component is fluorapatite [Ca10 (PO4) 6F2], followed by chlorine apatite and oxyhydrogen apatite. The phosphorus content varies greatly depending on the origin, with high levels of over 30% and low levels of only about 10%. Generally in the form of grayish brown powder, with a neutral reaction, it belongs to a insoluble delayed phosphate fertilizer.
The fertilizer efficiency of phosphate rock powder mainly depends on the content of available phosphorus, and the higher the content of available phosphorus, the better the fertilizer efficiency. The best phosphate rock powder is recognized as the Gafsa phosphate rock powder from Tunisia, North Africa. Its citric acid solubility (citric acid solubility) reaches over 60%, so its fertilizer efficiency is particularly good. The majority of phosphorus ore powder in China has a medium or higher solubility (10-20%). The phosphate rock powder made from limestone dissolved tung phosphate rock and bird droppings phosphate rock has a high solubility because its main component is tricalcium phosphate [Caz (PO4) 2]. Phosphate rock with low solubility is generally not suitable for direct application as phosphate rock powder.
Secondly, the fertilizer efficiency of phosphate rock powder is related to crop types. The ability of various crops to absorb and utilize phosphate rock powder is different. According to the comparative experiment of applying phosphate rock powder and superphosphate to different crops in the red soil area of Nanjing Soil Research Institute, the fertilizer effect of applying phosphate rock powder to rape, radish, and buckwheat is extremely significant; Potatoes, peas, rice beans, peanuts, milkvetch, etc. have significant fertilizer effects; Corn, potato, sweet potato, tomato box, sesame, etc. have medium fertilizer efficiency; The fertilizer efficiency of wheat, rice, millet, rye, oat, etc. is not significant.
Secondly, soil properties are also closely related to the fertilizer efficiency of phosphate rock powder. The most important factors are soil available phosphorus content and soil acidity. The available phosphorus content is high, but the fertilizer efficiency of phosphate rock powder is low. Only when the available phosphorus content in the soil is low, the fertilizer efficiency of phosphate rock powder is significant. The solubility of phosphate rock powder increases with the decrease of soil pH value, so only on acidic soil can phosphate rock powder show better effects.
