FRNL New Knowledge Register

block areas over 3 climate years. A hypothetical scenario, of a third of the platform in diverse pastures, less N fertiliser, all fodder beet grown on the milking platform, lifted and fed on the feed pad, and with an oats catch crop following fodder beet, increased production and profit by 2 and 10%, respectively, with a reduction in N leaching of 19%. • A scenario for the dairy and beef integrated FRNL monitor farm in North Canterbury on a light soil, implementing mixed species pasture, fodder beet and catch crops, reduced leaching by 19%. Average profitability was similar than if the farm was converted to dairy only, but with less variability between years due to variable weather and prices for milk and meat. • Modelling the farm system effects of pastures with 50% plantain on 28% of the pastoral area of another monitor farm, a high input Canterbury dairy farm on a free-draining soil, showed a reduction in leaching by 5%. This was the greatest reduction achieved by only substituting part of the standard pastures by mixed pastures containing plantain. While the diuresis effect of plantain reduced the N load in a urine patch, it also led to a larger area of the paddock covered by urine and a greater area covered by overlapping urine patches. Also, imported supplements negated some of the benefits of plantain. • Another modelling exercise demonstrated that greater reductions can be achieved when, in association with the diuresis effect of plantain, N fertiliser rate is reduced and a longer round length is adopted, which increases the C:N ratio of pasture. This scenario reduced pasture harvested by 8% for Canterbury and 16% for Waikato, and reduced N leaching by 31% for Canterbury and 59% for Waikato. This compared to reductions of 6% and 21% for the Canterbury and Waikato scenarios, respectively, for the diuresis effect only. • The farm system modelling indicated that high-performing farms have scope to reduce N leaching by 20% and still increase profit by implementing some of the FRNL mitigation options. P UBLICATIONS Beukes, P., Edwards, P. and Coltman, T. “Modelling options to increase milk production while reducing N leaching for an irrigated dairy farm in Canterbury”. Journal of New Zealand Grasslands 79 (2017): 147- 152. https://www.grassland.org.nz/publications/nzgrassland_publication_2859.pdf. Beukes P. C., Chikazhe, T. and Edwards, J. P. “Exploring options to reduce N leaching while maintaining profitability within a Canterbury farm business comprising several distinct enterprises”. New Zealand Journal of Grasslands 80 (2018): 191-194. https://www.nzgajournal.org.nz/index.php/JoNZG/article/view/324. Khaembah, E. N. and Horrocks, A. “A modelling approach to assessment and improvement of nitrogen management on New Zealand arable farms: a case study”. Agronomy New Zealand 48 (2018): 1-11. www.agronomysociety.org.nz/files/ASNZ_2018_01._Modelling_N_management.pdf. Romera, A. J., Doole, G. J., Beukes, P. C., Mason, N. and Mudge, P. L. "The role and value of diverse sward mixtures in dairy farm systems of New Zealand: An exploratory assessment”. Agricultural Systems 152 (2017): 18-26. https://doi.org/10.1016/j.agsy.2016.12.004. Vibart, R. E., Vogeler, I., Dodd, M. and Koolaard, J. "Simple versus Diverse Temperate Pastures: Aspects of Soil–Plant–Animal Interrelationships Central to Nitrogen Leaching Losses”. Agronomy Journal 108.6 (2016): 2174-2188. DOI: 10.2134/agronj2016.04.0193. https://dl.sciencesocieties.org/publications/aj/abstracts/108/6/2174. Vogeler, I., Vibart, R. and Cichota, R. "Potential benefits of diverse pasture swards for sheep and beef farming”. Agricultural Systems 154 (2017): 78-89. https://doi.org/10.1016/j.agsy.2017.03.015. Co-development for practice change to reduce nitrate leaching The monitor farmers collected an extensive amount of data on farm management, some daily, others monthly or annually. Farm performance was summarised annually.

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