Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, Harrow, ON, Canada.
J Environ Qual. 2010 Sep-Oct;39(5):1771-81. doi: 10.2134/jeq2009.0504.
Phosphorus (P) loss from agricultural land in surface runoff can contribute to eutrophication of surface water. This study was conducted to evaluate a range of environmental and agronomic soil P tests as indicators of potential soil surface runoff dissolved reactive P (DRP) losses from Ontario soils. The soil samples (0- to 20-cm depth) were collected from six soil series in Ontario, with 10 sites each to provide a wide range of soil test P (STP) values. Rainfall simulation studies were conducted following the USEPA National P Research Project protocol. The average DRP concentration (DRP30) in runoff water collected over 30 min after the start of runoff increased (p < 0.001) in either a linear or curvilinear manner with increases in levels of various STPs and estimates of degree of soil P saturation (DPS). Among the 16 measurements of STPs and DPSs assessed, DPS(M3) 2 (Mehlich-3 P/[Mehlich-3 Al + Fe]) (r2 = 0.90), DPS(M3)-3 (Mehlich-3 P/Mehlich-3 Al) (r2 = 0.89), and water-extractable P (WEP) (r2 = 0.89) had the strongest overall relationship with runoff DRP30 across all six soil series. The DPS(M3)-2 and DPS(M3)-3 were equally accurate in predicting runoff DRP30 loss. However, DPS(M3)-3 was preferred as its prediction of DRP30 was soil pH insensitive and simpler in analytical procedure, ifa DPS approach is adopted.
农田磷素通过地表径流流失会导致地表水富营养化。本研究旨在评估一系列环境和农业土壤磷测试方法，以作为指示安大略省土壤潜在地表径流溶解反应性磷（DRP）流失的指标。土壤样品（0-20 厘米深度）取自安大略省的六个土壤系列，每个系列有 10 个站点，以提供广泛的土壤测试磷（STP）值。按照美国环保署国家磷研究计划的方案进行了降雨模拟研究。在开始径流 30 分钟后收集的径流水中，DRP 浓度（DRP30）呈线性或曲线方式增加（p < 0.001），与各种 STP 水平和土壤磷饱和度（DPS）的估计值呈正相关。在所评估的 16 项 STP 和 DPS 测量中，DPS(M3) 2（ Mehlich-3 P/[ Mehlich-3 Al + Fe]）（r2 = 0.90）、DPS(M3)-3（ Mehlich-3 P/Mehlich-3 Al）（r2 = 0.89）和水可提取磷（WEP）（r2 = 0.89）与所有六个土壤系列的径流 DRP30 具有最强的整体关系。DPS(M3)-2 和 DPS(M3)-3 在预测径流 DRP30 损失方面同样准确。然而，如果采用 DPS 方法，DPS(M3)-3 更受欢迎，因为它对 DRP30 的预测对土壤 pH 不敏感且分析程序更简单。
