Increased rainfall may affect soil phosphorus (P) cycling in tropical forest ecosystems, yet the key biotic and abiotic factors that govern soil organic P transformations remain unclear. In this study, we conducted a long-term (7 years) rainfall manipulation experiment in the field to examine the effects of increased rainfall (+25%) in the wet season on soil P dynamics in a tropical forest. We found that an increase in rainfall in the wet season enhanced the maximum P adsorption capacity of forest soil as a result of a greater availability of soil organic matter and organic iron (Fe)/aluminum (Al) oxides. Newly formed stable ternary complexes between soil organic matter, metals (Mn, Mg and Ca) and P increased the surface adsorption of soil organic P. Moreover, the alkaline phosphomonoesterase (ALP) activity was reduced under our experimental treatment owing to a decrease in the abundance of both ALP-producing bacteria (Bradyrhizobium and Methylobacterium being the dominant genera) and bacterivores (Rhabditis and Acrobeloides). Our findings demonstrated an overall negative impact of elevated rainfall in wet season on soil organic P decomposition in tropical forests through the enhancement of soil P adsorption capacity and the inhibition of soil ALP activities. Our results implied that a long-term rainfall increase in the wet season could increase soil organic P accumulation, which in turn further reduce soil P availability for plant uptake in the tropical forests.

降雨增加可能会影响热带森林生态系统中土壤磷（P）的循环，但是控制土壤有机磷转化的关键生物和非生物因素仍然不清楚。在这项研究中，我们在田间进行了长期（7年）降雨操纵实验，以检验湿季降雨增加（+ 25％）对热带森林土壤P动态的影响。我们发现，由于土壤有机质和有机铁（Fe）/铝（Al）氧化物的可用性更高，因此雨季降雨增加增加了森林土壤对磷的最大吸附能力。土壤有机质，金属（锰，镁和钙）与磷之间新形成的稳定的三元络合物增加了土壤有机磷的表面吸附。缓生根瘤菌和甲基杆菌是主要的属）和噬菌体（横纹肌炎和Acrobeloides）。我们的研究结果表明，雨季降雨增加对土壤有机磷分解的总体负面影响是通过提高土壤对磷的吸附能力和对土壤ALP活性的抑制作用。我们的结果表明，雨季的长期降雨增加会增加土壤有机磷的积累，进而进一步减少热带森林中植物吸收磷的有效性。