Reduction of agricultural nitrogen inputs into waters: the effectiveness of the Hessian WFD advisory service.
In addition to other nitrogen sources, nitrogen emissions from agriculture pollute waters and other environmental media, both in Germany and in other countries of the European Union and worldwide. To convince farmers of management changes, in addition to regulatory and economic instruments, advisory tools are used and discussed for future policy-making. However, there are very limited possibilities to assess the effectiveness of advisory services, and therefore it is unclear what the costeffectiveness of advisory services for water protection is. To help solve this problem, a case study was carried out by analyzing the impact of the Hessian water protection advisory service in the context of the EU Water Framework Directive on nitrogen emissions with a set of indicators based on empirical and theoretical principles. The core of the study was a standardized survey that allowed quantitative analyses using responses from 1.477 advised and non-advised farmers. The standardized survey was supplemented in the preparation mainly by expert interviews and after the survey by validation rounds with advisors and farmers as well as by transcripts of 18 qualitative in-depth interviews with farmers. Results show that even though for the only available goal indicator, nitrogen balances, a very poor data situation was given, in combination with different process indicators on the levels of farmers; decision-making and farm management it could be interpreted in a meaningful way. Reductions of N surpluses of 2 to 5.5 kg N/ha per year were estimated as the effect of the advisory services, resulting in a cost efficiency of 8 to 26 Euro per kg of avoided nitrogen emission. Additionally, synergies with other policy goals, such as soil and biodiversity conservation, as well as with other policy instruments have to be acknowledged. Furthermore, results show that after only two years duration the advisory service had not realized its potential and the results of a later assessment should show higher effectiveness and cost-effectiveness of the advisory service. The results of the case study are discussed in the light of other studies, and factors for the success and comparability of advisory services as well as for the use of advisory services in the policy mix are presented. Also the methodology, the applied model and the chosen indicators are discussed.