The importance of validated ecological indicators for manure regulations in the Netherlands

The termination of the EU milk quota system on April 1, 2015 is leading to an increase in manure production in the Netherlands. Rather than focus on the quality of water and nature, of which at least the water quality has strongly improved during the last decades, discussions appear to center on strengthening proxy measures that are already being used and which are only remotely related to the quality issue. The quality of water and nature is determined for ground- and surface water by first measuring their N and P content and for nature areas the N deposition. When these values are higher than threshold values determined by ecologists, quality is inadequate and measures are needed. When values are lower, quality is adequate. Three basic problems need to be addressed: (i) threshold values are in practice considered to be permanent while they should be dynamic reflecting a learning process when comparing measurements of N and P values on the one hand and a simultaneous ecological characterization on the other. This requires more cooperation between soil scientists, hydrologists and ecologists. Dynamic characterization may well lead to locally different threshold values. (ii) many measurements of water quality are being made but hardly any measurements of N deposition on nature areas. Such measurements are needed to allow judgements as to the effect of agricultural practices on nature quality. (iii) The necessary further improvement in water and nature quality, as far as it is affected by agricultural practices, can only be achieved when farmers are fully committed and engaged. The current top-down regulations with a "command-and-control" character, while effective in the 1990s, cannot serve this purpose in the information age, the more so since farmers are increasingly well educated and ask too many questions that are not being answered. The suggestion is made to change the generic character of the legislation ("one size fits all") to a system where "tailor made" management systems are designed for individual farms,considering environmental conditions in the area where the farm occurs. Researchers and farmers can work together in a joint-learning mode to develop such designs that can be recognized by certificates with a legal status. In any case, the proportionality principle needs to be considered assuring that the severity of measures taken are in balance with societal effects. (C) 2016 Elsevier Ltd. All rights reserved.