Inorganic P is adsorbed by a variety of soil minerals. For acidic subtropical Alfisols with high contents of both (hydr)oxides and clay minerals, there is an underappreciated understanding of the importance of clay minerals to P species and availability varying with soil pH and P concentration. In this study, the rate and equilibrium of P adsorption in a subtropical Alfisol were investigated by combining soil incubation with three types of P fertilizer with multi-surface modelling. Phosphorus species analysis revealed that most of the P was present in the forms of Al-P and Fe-P in the subtropical Alfisol. The multi-surface model calculation showed that goethite, kaolinite, and illite were the most important soil constituents responsible for the immobilization of P. Clay minerals were as important as Al/Fe (hydr)oxides for P adsorption in the subtropical Alfisol. In addition, there was a highly positive linear correlation between P adsorbed by illite and Olsen P, with a slope of approximately to 1. The model analysis also showed that >99% of the P adsorbed by illite was in the form of ${\left(-SO\right)}_{2}P{O}_2^{2-}$. These results suggest the important role of illite in controlling P availability and that P adsorption by illite may serve as an indicator of P availability in the subtropical Alfisol.

无机磷被多种土壤矿物质吸附。对于（氢）氧化物和粘土矿物含量高的酸性亚热带 Alfisols，人们对粘土矿物对 P 物种的重要性以及可用性随土壤 pH 值和 P 浓度变化的认识不足。在这项研究中，通过将土壤培养与三种类型的磷肥结合多表面建模，研究了亚热带 Alfisol 中磷的吸附速率和平衡。磷种类分析表明，在亚热带 Alfisol 中，大部分 P 以 Al-P 和 Fe-P 的形式存在。多表面模型计算表明，针铁矿、高岭石和伊利石是导致 P 固定化的最重要的土壤成分。对于亚热带 Alfisol 中的 P 吸附，粘土矿物与 Al/Fe（氢）氧化物一样重要。此外，伊利石吸附的P与Olsen P之间存在高度正线性相关，斜率约为1。模型分析还表明，>99%的伊利石吸附P的形式为${\left(——秒哦\right)}_2磷{哦}_2^{2——}$. 这些结果表明伊利石在控制磷有效性方面的重要作用，并且伊利石对磷的吸附可以作为亚热带 Alfisol 中磷有效性的指标。