促释磷肥的结构特征及其有效性机理研究

【目的】揭示促释磷肥结构特征与磷素有效性的内在联系，探讨促释磷肥的有效性量化测定方法。【方法】采用连续浸提和乙酸-乙酸钠测活性磷法，通过再活化手段及光谱学技术从持续活化能力及理化结构特征方面揭示促释磷肥的有效性机理。【结果】木质素磺酸钠处理能显著提高磷矿粉的水溶性磷和活性磷含量，4种促释磷肥的8次累积水溶性磷含量分别是对应磷矿粉的14.0、5.6、8.8和5.1倍；且乙酸-乙酸钠测得的活性磷与未处理磷矿粉相比，提高了9.8%—93.1%。红外光谱和X-衍射分析结果表明，木质素磺酸钠对磷矿粉磷素的促释作用具有持续性，能有效改变磷矿粉本身的化学成键结构，促使难溶的或枸溶Ca-P键转化为活性高的H2PO42-，降低磷灰石结晶程度，提高其有效性。【结论】促释处理能持续促进难溶性或枸溶性磷向活性磷转化，采用连续浸提和乙酸-乙酸钠测活性磷法能够对促释效果进行评价。

Research on the Structural Characteristics of Promoted-Release Phosphate Rocks and Its Phosphorus Bioavailability Mechanism

【Objective】The objective of the study is to disclose the structural characteristics and their internal relation with phosphorus validity in the promoted-release phosphate rocks (PRPr), and discuss the method for quantitative determination of active phosphorus.【Method】Continuous water extraction (CWE) and digestion with acetic acid and sodium acetic mixture (ASA) were involved, and the re-activated experiments and spectroscopic techniques were carried out to explore the phosphorus validity mechanism of PRPr from promoted-release persistence and molecular structure.【Result】The water-soluble phosphorus and active phosphorus in PRPrs treated by sodium lignosulphonate (SL) increased significantly. Compared with the phosphate rocks, the accumulative release rates of phosphorous of four PRPrs were 14.0, 5.6, 8.8 and 5.1 times higher and active phosphorus in PRPrs increased by 9.8%-93.1%, respectively. The results of infrared spectrum (IR) and X-ray diffraction（XRD）analysis showed that the characterastic abasorption spectrum of H2PO42- was strengthened or new characterastic absorption spectrum of H2PO42- appeared, the structure of apatite crystal was destroyed and amorphous apatite increased. These constantly made insoluble and citrate-soluble phosphorus in phosphate rock changed into active status and improved the bioavailability of phosphorus.【Conclusion】The promoted-release treatment could significantly improve the bioavailability of phosphorus in phosphate rock through constantly translate insoluble and citrate-soluble phosphorus into active status. The continuous water extraction and ASA can be used to make a proper assessment on bioavailability of PRPrs.