超微活化条件对磷矿粉磷素形态及肥效的影响

采用化学分析、红外光谱分析以及盆栽试验研究了活化剂添加量及研磨时间对超微活化磷矿粉磷素形态及生物有效性的影响.结果表明,与普通磷矿粉相比,磷矿粉经超微活化处理后有效磷提高了45.1％～58.7％,活性磷提高了169.4％～203.6％,水溶性磷含量随活化剂添加量的增加也明显提高；当活化剂添加量达到5％时,3次水溶性磷的累积释放量较相同条件下制得的超微细磷矿粉提高84倍以上.适当延长研磨时间有利于磷矿粉磷素的释放,但效果不显著.红外光谱分析结果表明:超微细活化磷矿粉中与PO3-、HPO2-相关的特征吸收峰强度较普通磷矿粉显著增强,且生成了与PO43-、HPO42-相关的新特征吸收峰,使磷矿粉中的磷向有效状态转变.盆栽试验结果进一步表明,超微活化磷矿粉处理的玉米生物量、磷素利用率均显著高于磷矿粉、普通超微细磷矿粉以及过磷酸钙和磷酸二铵等常规水溶性磷肥,可增强抗固定能力而显著提高土壤有效磷含量.超微活化磷矿粉较高的活性磷总量和水溶性磷持续适度的供磷强度是其生物有效性高的原因.

Phosphorus availability and fertilizer efficiency of rock phosphate as affected by ultrafine activation

The ultrafine activated rock phosphate (UARP) was prepared and its phosphorus availability and fertilizer efficiency as affected by amendment of activator and grinding was studied using chemical analysis, infrared spectrum (IR) analysis and pot experiment. Results show that the fractions of available phosphorus and labile phosphorus in UARPs increased by 45.12%~58.68% and 169.38%~203.61%, respectively. The fraction of water-soluble phosphorus in UARPs increased markedly with the amount of activator added. When the activator was added to make 5% of the UARP, the accumulative water-soluble phosphorus release rate of the fertilizer increased by more than 84 times. Proper extension of grinding time contributed to release of phosphorus from the product, but the effect was not significant. Infrared spectrum (IR) analysis shows that the PO43- and HPO42--related characteristic absorption peaks of UARPs were much higher in intensity than those of common RP, thus forming new characterastic absorption peaks, which indicates that phosphorus in rock phosphate powder is turned to be available. Results of the pot experiment indicate that Treatment UARP was much higher than Treatments RP and UFRP in corn biomass and fertilizer use efficiency, and even higher than Treatments SP (superphosphate) and DAP (diammonium phosphate), and that UARP significantly increased available phosphorus by reducing fixation of phosphorus in the soil. The relatively high content of labile phosphorus and the sustained moderate phosphorus supply level of water-soluble phosphate in UARP were the main causes of its high bioavailability.