The effect and mechanism of improved efficiency of physicochemical pro-release treatment for low grade phosphate rock

Abstract

With the increasingly acute contradictions between shortage of bonanza phosphorus resources and phosphate fertilizer demands, to develop an efficient use technology for low-grade phosphate rocks (LGPR) was an inevitable choice. In this study, the physicochemical pro-release phosphate rock (PCPR) was prepared by adding modified lignin during the process of ultra-fine grinding LGPR. The relationship between phosphorus chemical composition of PCPR, molecular structure and fertilizer efficiency was explored by chemical analysis, spectral analysis and pot experiment. The results showed that after pro-release treatment of phosphate rock (PR), available phosphorus, reactive phosphorus and soluble phosphorus levels were significantly increased compared with PR. The available phosphorus content increased by 40%, the reactive phosphorus content increased more than 3.5 times, and 6 consecutive extraction soluble phosphorus accumulation increased by 24 times. The structure of the PR showed the pro-release processing would significantly increase particle fineness and specific surface area of PR , strengthen the characteristic absorption peak intensity of PO 4 3-, HPO 4 2-, replace the Cl -, F -, Fe 2+ in the apatite and change the phase composition of PR. Pot experiment results showed corn biomass and phosphorus utilization processed by the PCPR were much higher than superphosphate (SP), diammonium phosphate(DAP), and significantly improve soil phosphorus content. The high soluble phosphorus and active phosphorus in PCPR providing the moderate continuous phosphorus supply intensity was the main reason for its high bioavailability. The combination of a static extraction and continuous extraction of reactive phosphorus and soluble phosphorus was an appropriate evaluation of physicochemical pro-release effect.

Exploring phosphorus fertilizers and fertilization strategies for improved human and environmental health

“…However, finely ground phosphate rock has been shown to insufficiently improve phosphate rock effectiveness (Ibrahim et al 2010). To further improve efficacy, ultra-fine grinding of phosphate rock to 10-20 μm and combining with lignin which activates the phosphate rock has been found to enhance P uptake to levels comparable to, if not better than, water-soluble P fertilizers in pot experiments (Huang et al 2014). Combining equal amounts of water-soluble P fertilizers, such as single superphosphate or triple superphosphate, with phosphate rock increases the uptake of P from the phosphate rock by 100% or more, when compared with sole phosphate rock application (Chien et al 1996).…”

Sulfur-Enriched Bone Char as Alternative P Fertilizer: Spectroscopic, Wet Chemical, and Yield Response Evaluation

“…Common extracts to evaluate P solubility from mineral P fertilizers are, with increasing P-extractability, water, neutral ammonium citrate (NAC), citric acid (CA), and mineral acids (sulphuric and nitric acid) [26,27]. The water extract represents P, which is directly or in a short-term plant-available and is, therefore, used to assess labile P in soils [28,29] and mineral P fertilizers [30]. The NAC extract is commonly used to estimate plant-available P from mineral P fertilizers (e.g., [31,32]), dissolving mono-and dicalciumphosphates (MCP and DCP), some Al-and Fe-phosphates and some alkaline Ca-phosphates such as HA ( [33] and references therein).…”

An Indigenous Soil Bacterium Facilitates the Mitigation of Rocky Desertification in Carbonate Mining Areas

“…Certain bacteria can convert mineral P into soluble dihydrogen phosphate (H 2 PO4 − ) and hydrogen phosphate (HPO 4 2− ) ions through the secretion of organic acids, and these ions subsequently were absorbed by plants (Richardson & Simpson, ). K, which is also essential for plant growth, is usually deficient in soil solution but is abundant in the mineral soil (Huang et al , ). A variety of Bacillus species were screened as mineral potassium‐solubilizing bacteria to release the effective K for plant growth (Hu et al , ; Uroz et al , ).…”