The effects of long-term excessive phosphorus (P) fertilization on the P fraction changes and P loss risk in orchard soils remain unclear. This study aimed to assess the concentrations of and relationships among the soil total P (TP), Olsen-P and P fractions in pomelo orchard (PO) soil during different fertilization periods. The PO soils were in a severe P overapplication state (905.4 kg P₂O₅ ha^-1 yr^-1), with a high P surplus (773.5 kg P₂O₅ ha^-1 yr^-1) and low P use efficiency (PUE, 14.7%). Such long-term excessive fertilizer P input significantly increased the TP, Olsen-P, and P fraction concentrations and significantly reduced the proportions of Org-P and reduction-P (Red-P) in both the surface (0–20 cm) and subsurface (20–40 cm) soils but increased the proportions of easily soluble P (Sol-P), aluminum-P (Al–P) and iron-P (Fe–P) rather than calcium-P (Ca–P). Furthermore, the P fractions exhibited a corresponding increasing trend and a significant linear (or two-stage linear) relationship with the soil P surplus. There is a serious risk of P loss when the P surplus in the surface soil exceeds 4128 kg P ha^-1. Al–P had the highest correlation with Olsen-P (R = 0.984, p < 0.01), followed by Sol-P, Fe-P, Ca-P, Org-P and Red-P (R = 0.973, 0.908, 0.8783, 0.820 and 0.697, respectively, p < 0.01). However, only Sol-P and Al–P had a major direct impact on Olsen-P. In general, long-term excessive P application exerted a remarkable and differentiated impact on the soil P fractions. An increase in the Sol-P and Al-P fractions could lead to enhanced P bioavailability and environmental risk in acidic red soils. Therefore, P management in the PO production system needs to control the P fertilizer input and monitor the soil P fractions, which merits further investigation.

长期过量施磷对果园土壤磷含量变化和磷流失风险的影响尚不清楚。本研究旨在评估不同施肥时期柚园（PO）土壤中土壤全磷（TP）、Olsen-P和P组分的浓度和关系。PO 土壤处于严重的 P 过量施用状态（905.4 kg P ₂ O ₅ ha ^-1 yr ^-1），P 过剩（773.5 kg P ₂ O ₅ ha ^-1 yr ^-1）) 和低磷利用效率（PUE，14.7%）。这种长期过量施磷显着增加了 TP、Olsen-P 和 P 组分浓度，并显着降低了地表（0-20 cm）和地下（20-40 厘米）土壤，但增加了易溶 P (Sol-P)、铝-P (Al-P) 和铁-P (Fe-P) 的比例，而不是钙-P (Ca-P)。此外，P 部分表现出相应的增加趋势，并与土壤 P 过剩呈显着的线性（或两阶段线性）关系。当表层土壤中磷过剩超过4128 kg P ha ^-1时，存在严重的磷流失风险。Al-P 与 Olsen-P 的相关性最高（R = 0.984，p < 0.01)，然后是 Sol-P、Fe-P、Ca-P、Org-P 和 Red-P（分别为 R = 0.973、0.908、0.8783、0.820 和 0.697，p  < 0.01）。然而，只有 Sol-P 和 Al-P 对 Olsen-P 有重大的直接影响。一般而言，长期过量施磷对土壤磷含量产生显着且差异化的影响。Sol-P 和 Al-P 组分的增加可能导致酸性红壤中 P 生物有效性和环境风险的增加。因此，PO 生产系统中的磷管理需要控制磷肥的输入和监测土壤磷的比例，这值得进一步研究。