Exploring options to reduce nitrogen leaching while maintaining profitability within a Canterbury farm business comprising several distinct enterprises

Abstract

This paper reports on a study evaluating the effects of nitrogen (N) mitigations on N leaching and profitability across all hectares of a farm business consisting of a dairy platform, dairy support and beef blocks. Two different models were used, each with their own strengths and weaknesses. Mitigation options focussed on N fertiliser use, plantain-ryegrass-clover diverse pastures, cropping regime, and animal and feed movements between the blocks. A combination of less N fertiliser, replacing kale with fodder beet for wintering to reduce the crop area, an oats catch-crop following autumn-harvested fodder beet, diverse pastures on a proportion of platform and support blocks, and wintering non-pregnant cows on the beef block reduced N leaching by 19%. Profitability was not affected by these mitigations. Profitability did not increase, but N leaching did, when changing to an all-dairy business model. Nitrogen leaching reductions can be achieved if all enterprises implement some or all of these mitigations.