Characterizing the vertical distribution of total phosphorus (P) and P forms in streambanks can improve estimates of P loads to streams via bank erosion. Using a systematic literature review, this meta-analysis evaluated the vertical distribution of total P (P_tot), Bray-1 test P (P_Bray1), oxalate-extractable P (P_ox), degree of P saturation (DPS_ox), and soil P storage capacity (SPSC) at 161 streambank locations encompassing diverse soil orders and riparian land covers. Across studies, maximum soil sampling depth (125 cm) was on average half that of streambank height (250 cm on average), and water quality-related P fractions such as water-extractable P (P_w) were not generally reported. Slightly weathered Entisols and Inceptisols collectively accounted for 84% of observations, likely reflecting alluvial deposition environments along stream corridors, and exhibited decreasing P_tot (820 to 400 mg kg⁻¹) with increasing depth to 200 cm. Irregular changes in P_tot at depth > 200 cm of Entisols and Inceptisols suggested burial of organic-rich A horizons by alluvial deposition. Changes in riparian land cover mainly affect P_tot in the upper 60 cm, with depth-weighted mean P_tot increasing as grassland (217 mg kg⁻¹) < forest (628 mg kg⁻¹) ≈ wetland (624 mg kg⁻¹) < developed (684 mg kg⁻¹) < agriculture (739 mg kg⁻¹), consistent with expected anthropogenic P enrichment of surface soils and posing increased P loading risk. Effect size analysis showed that riparian land cover had a large influence on P_tot within the top 30 cm depth whereas soil order and bedrock type had large influences on subsurface P_tot, suggesting depth-divergent drivers of P in streambank soils. Additionally, P_tot and P_ox were positively correlated with silt, clay, carbon, cation exchange capacity (CEC), oxalate-extractable iron (Fe_ox) and aluminum (Al_ox), and total Fe (Fe_tot) contents. This work helps advance understanding of the vertical variation of streambank soil P across diverse soil types, land covers, and soil properties, and their implications for P loading from bank erosion. We also identify gaps in sampling approaches (insufficient depth) and analysis (P_w) that may be hindering comprehensive assessment of bank erosion P loading and risk to water quality. Finally, we illustrate how fluvial erosion and deposition may generate complex vertical P distributions in streambanks, with implications for estimating erosional P loading that can benefit from a pedologically explicit approach.

表征河岸中总磷 (P) 和 P 形式的垂直分布可以改进通过河岸侵蚀对河流 P 负荷的估计。使用系统文献回顾，该荟萃分析评估了总磷 (P _tot )、Bray-1 测试 P (P _Bray1 )、草酸盐可萃取磷 (P _ox )、磷饱和度 (DPS _ox ) 的垂直分布， 161 个河岸位置的土壤磷储存能力 (SPSC)，包括不同的土壤顺序和河岸土地覆盖。在所有研究中，最大土壤采样深度（125 厘米）平均是河岸高度（平均 250 厘米）的一半，而与水质相关的 P 分数，如水可提取 P (P _w) 一般没有报道。轻微风化的 Entisol 和 Inceptisol 共占观测的 84%，可能反映了河流走廊沿线的冲积沉积环境，并且随着深度增加到 200 cm， P _tot下降（820 到 400 mg kg ^{-1 ）。}_{在深度 > 200 cm 的 Entisol 和 Inceptisol 处 P tot}的不规则变化表明冲积沉积埋藏了富含有机物的 A 层位。河岸土地覆盖的变化主要影响上部 60 cm 的_Ptot，深度加权平均_Ptot随着草地 (217 mg kg ^-1 ) < 森林 (628 mg kg ^-1 ) ≈ 湿地 (624 mg kg ^-1 )增加< 发达（684 毫克公斤^-1 ) < 农业 (739 mg kg ^-1 )，与预期的表层土壤人为富集 P 相一致，并增加了 P 负荷风险。效应大小分析表明，河岸土地覆盖对顶部 30 cm 深度内的_Ptot影响很大，而土壤顺序和基岩类型对地下_Ptot影响很大，表明河岸土壤中 P 的深度发散驱动因素。此外，P _tot和 P _ox与粉砂、粘土、碳、阳离子交换容量 (CEC)、草酸盐可萃取铁 (Fe _ox ) 和铝 (Al _ox ) 以及总铁 (Fe _tot） 内容。这项工作有助于加深对不同土壤类型、土地覆盖和土壤特性的河岸土壤 P 的垂直变化及其对河岸侵蚀引起的 P 负荷的影响的理解。我们还确定了采样方法（深度不足）和分析（P _w）方面的差距，这些差距可能会阻碍对河岸侵蚀 P 负荷和水质风险的全面评估。最后，我们说明了河流侵蚀和沉积如何在河岸中产生复杂的垂直 P 分布，这对估计可以受益于土壤学明确方法的侵蚀 P 负荷具有影响。