Developing an approach to select nitrogen loss mitigations for temperate pasture‐based dairy farms

The purpose of this study was to identify intensive pastoral farming practices with high nutrient inputs that contribute to nitrogen (N) loss to the environment, with a focus on New Zealand dairy systems. Barriers to adoption of N mitigation strategies include uncertainty regarding the impact and complementarity of the mitigations. The purpose of this study was to identify and develop a process for determining which N leaching mitigations are likely to complement each other when stacked together in a grazed pastoral dairy farm system and could thereby provide additive benefits towards achieving substantial reductions in N leaching. A list of mitigations for reducing N loss are presented and discussed. The review highlights the importance of the mechanism of N loss, and that by adopting N mitigations with different mechanisms, users can combine practices with complementary effects on reducing N loss. The review also acknowledges that successful N mitigation requires knowledge at tactical and operational levels. There are limited decision support tools available for farmers to assist them with the use of N mitigations that are suitable for individual circumstances. Consequently, the review suggests opportunities for provision of tactical and operational indicators.