Implementation of the EU Nitrates Directive in Germany—a critical review

Abstract

Abstract Background Under the EU Nitrates Directive, Member States are required to adopt suitable measures to comply with the limit value of 50 mg NO 3 l −1 in groundwater. In Germany, the Fertiliser Application Ordinance (Düngeverordnung; DüV) defines the code of good agricultural practice with regard to nitrogen fertilisation. More than 30 years after the ordinance first came into force, the deficits and the ineffectiveness of the German water protection policies are evident. After a number of court rulings, the German Federal Government is now under considerable pressure to effectively implement the EU Nitrates Directive. Findings Since the amendments to the DüV in 2017 there has been a decline in the nitrogen inputs and the nitrogen surplus in plant production, but the proportion of the monitoring sites exceeding the nitrate limit value in groundwater has only gone down slightly over two decades. There has been no decrease in the amount of soil mineral nitrogen in autumn or the nitrate concentration in leachate in the representative test regions monitored under the DüV. After 30 years of accumulation of nitrogen surpluses resulting in a huge amount of labile nitrogen fractions in arable soils, the DüV continues to stipulate excessive nitrogen fertiliser requirement for crops and does not take sufficient account of nitrogen mineralisation from soil. Generally, the current values given for the nitrogen fertiliser requirement of some of the main crops are driven by a yield maximisation purpose and not by environmental protection needs. Conclusions A science-based revision of the DüV should recalibrate the nitrogen requirements for crops, the specifications for nitrogen availability from soil, define minimum standards for crop rotation design, including catch crops and the alteration between winter and spring crops, and limit the application of organic fertilisers to 120 kg N per ha on arable land. Overall, the DüV should be fully aligned with the goal of the Fertiliser Act, namely to avoid, as far as possible, the loss of nutrients into the environment and to ensure compliance with the limit values for nitrates in groundwater.