Maximum potential nitrate discharge hazard (federal method)

The maximum potential risk of nitrate discharge is used to assess the maximum risk of nitrate leaching from the root space of vegetation by leaching soil water. The location of the assessment is the lower bound of the rooted soil layer. The ratio of leachate rate and usable field capacity in the effective root space (nFKWe) first provides the exchange frequency of the plant-available soil water. This is classified in 5 stages (very low – very high) and gives the pNAG. The characteristic value of the potential risk of nitrate discharge is not suitable for deriving quantitative statements, as use-dependent influencing variables (e.g. crop type, quantities of nitrogen added and removed, autumn nitrate content in the soil) are not taken into account. The calculation of the potential nitrate discharge risk according to the federal method is based on the evaluation method 5.3 (AG Boden, 2000b). Further information can be found here: https://geo.brandenburg.de/karten/htdocs/21042020_Sickerwasserrate.pdf本方法以硝酸盐淋失（nitrate discharge）最大潜在风险为评价指标，通过土壤水淋洗过程评估植被根区（root space）的硝酸盐淋溶最大风险，评价位置设定为根系土层的下界。有效根区（effective root space）内渗沥速率与有效田间持水量（usable field capacity）的比值（nFKWe），可表征植物有效土壤水的交换频次。该比值被划分为5个等级（极低至极高），并由此得到pNAG指标。由于该方法未纳入与实际应用相关的影响变量，例如作物类型、氮素投入与移除量、土壤秋季硝酸盐含量等，因此硝酸盐淋失潜在风险的特征值不适用于推导定量结论。基于联邦方法的硝酸盐淋失潜在风险计算，依据评价方法5.3（AG Boden, 2000b）开展。更多详细信息可参阅：https://geo.brandenburg.de/karten/htdocs/21042020_Sickerwasserrate.pdf