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

Abstract

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.