The persistent environmental relevance of phosphorus (P) and P sorption capacity (PSC) on P loss to surface waters has led to proposals for its inclusion in soil fertility and environmental management programs. As fertility and environmental management decisions are made on a routine basis, the use of laborious P sorption isotherms to quantify PSC is not feasible. Alternatively, pedotransfer functions (pedoTFs) estimate PSC from routinely assessed soil chemical properties. Our objective was to examine the possibility of developing a suitable pedoTF for estimating PSC and to evaluate subsequent PSC-based indices (P saturation ratio [PSR] and soil P storage capacity [SPSC]) using data from an in-field laboratory where tile drain effluent is monitored daily. Phosphorus sorption capacity was well predicted by a pedoTF derived from soil aluminum and organic matter (R² = .60). Segmented-line relationships between PSR and soluble P were observed in both desorption assays (R² = .69) and drainflows (R² = .66) with apparent PSR thresholds in close agreement at 0.21 and 0.24, respectively. Negative SPSC values exhibited linear relationships with increasing soluble P concentrations in both desorption assays and drainflows (R² = .52 and R2 = .53 respectively), whereas positive SPSC values were associated with low SP concentrations. Therefore, PSC-based indices determined using pedoTFs could estimate the potential for subsurface soluble P losses. Also, we determined that both index thresholds coincided with the critical soil-test P level for agronomic P sufficiency (22 mg kg-1 Mehlich-3 P) suggesting that the agronomic threshold could serve as an environmental P threshold.

中文翻译：

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磷吸附能力的发展——基于瓷砖排水系统的环境指标

磷 (P) 和磷吸附能力 (PSC) 对地表水磷流失的持续环境相关性导致建议将其纳入土壤肥力和环境管理计划。由于肥力和环境管理决策是在常规基础上做出的，使用费力的 P 吸附等温线来量化 PSC 是不可行的。或者，土壤转移函数 (pedoTFs) 从常规评估的土壤化学特性中估计 PSC。我们的目标是检查开发合适的 pedoTF 以估计 PSC 的可能性，并使用来自田间实验室的数据评估基于 PSC 的指数（P 饱和率 [PSR] 和土壤 P 储存容量 [SPSC]），其中瓷砖排水每天对污水进行监测。来自土壤铝和有机质 (R² = .60) 的 pedoTF 很好地预测了磷吸附能力。在解吸分析 (R² = .69) 和排水流 (R² = .66) 中观察到 PSR 和可溶性 P 之间的分段关系，表观 PSR 阈值分别为 0.21 和 0.24，非常一致。在解吸分析和排水流中，负 SPSC 值与增加的可溶性 P 浓度呈线性关系（分别为 R² = .52 和 R2 = .53），而正 SPSC 值与低 SP 浓度相关。因此，使用 pedoTFs 确定的基于 PSC 的指数可以估计地下可溶性 P 损失的潜力。还，