Future Farming Systems trial work by Northland Dairy Development Trust at the 100-year-old Northland Agricultural Research Farm has thrown up many questions in Year 3 of a five-year term.
Three completed seasons of the study have shown quite different results, the annual Northland Dairy Development Trust, or NDDT, field day was told in late June.
The report was presented by the science manager for the trial, Chris Boom, and NDDT trustee Kim Robinson, both also farm consultants with AgFirst Northland.
The Future Farming Systems trial is investigating pasture systems in a warming climate and when conforming to the government’s greenhouse gas emissions targets.
The Northland Agricultural Research Farm, or NARF, is a high-producing dairy farm by Northland standards and has historical average pasture growth of 15.4 tonnes dry matter per hectare per year on kikuyu-dominant pastures. Ryegrass persistence is poor, rust and pest damage are increasing and regression to kikuyu often occurs within three years of sowing new pastures.
This study compares a typical Northland dairy farm system – Baseline Farm: kikuyu/ryegrass pastures, 3.1 cows/ha, up to 190 kg N/ha applied – with a farm that has over 70% of land in tall fescue/cocksfoot/clover/chicory pastures – Alternative Pastures Farm: 3.1 cows/ha, up to 190 kg N/ha – and a farm designed to have significantly reduced greenhouse gas emissions – Low Emissions Farm: kikuyu/ryegrass pastures, 2.2 cows/ha, no N applied.
Pasture and milk production, milk composition, profit and people (labour input and management difficulty) are all measured. Milk production was highest on the Baseline Farm in the first season (2021-22), which featured a particularly dry summer.
In the second and third seasons production was highest on the Alternative Pastures Farm.
Milk production/ha on the lower stocked Low Emissions Farm has ranged between 25% and 39% lower than the Baseline Farm.
The variation in milk production on the Low Emissions Farm appears to be related to clover presence, which has been significantly higher with the removal of N fertiliser from the system.
Financial analysis of each farm (using actual milk price) shows the Alternative Pastures Farm has been the most profitable in two of the three seasons.
Profit on the Low Emissions Farm has been lowest except for the 2022-23 season, when better production and significant inflation in input costs combined to boost profit above that of the Baseline Farm. Averaged over the three years, however, profit was 31% lower than the Baseline Farm.
Averaged across the three seasons to date, the Low Emissions Farm has shown GHG reductions closer to targets compared to the Baseline Farm.
The methane reductions have been more variable, partly due to fluctuating milk production per cow.
Emissions intensity (GHG/kg MS) has improved, primarily through a reduction in the embedded emissions in imported feed and nitrogen fertiliser.
This project expected to reduce methane emissions by 25% and nitrous oxide emissions by 50% on the Low Emissions Farm compared to the Baseline Farm.
The actual (modelled) reduction so far has averaged 28% and 48% respectively, which is somewhat in line with the reduction in stocking rate and milk production.
The study has provided results under contrasting climatic conditions.
So far, extended dry summers appear to favour kikuyu/Italian ryegrass-based pastures, whereas the Alternative Pastures Farm performed well in the normal to wetter summer rainfall seasons.
Removing nitrogen fertiliser on the Low Emissions Farm quickly resulted in a significant increase in clover presence, particularly in the 2022-23 season until flooding from cyclone Gabrielle eliminated clover from much of the farm.
Clover content in pastures over the three years has averaged 8% on the Baseline Farm (with N) and 22% on the Low Emissions Farm (no N).
Variation in performance of this farm indicates how dependent no-nitrogen systems are on clover presence.
This project will continue for two more seasons allowing testing of these regimes over further variable climatic conditions and display any compounding treatment effects over time.
The Alternative Pastures Farm was set up by sowing 74% of the farm area during 2020 and 2021 with tall fescue, cocksfoot, white and red clovers and chicory. Plantain and Persian clover were added in some paddocks.
Between 15-20% of these alternative pastures have been resown each autumn, apart from autumn 2023 when 60% of these pastures were resown after damage from Cyclone Gabrielle.
Costs of the pasture introduction have been similar across each year, averaging $1,138/ha sown, including tractor time, man hours and contractor costs for drilling.
The other two farms (Baseline Farm and Low Emissions Farm), and the 26% portion of the Alternative Pastures Farm that was not sown in new species, have older pastures with approximately 70% kikuyu presence.
All kikuyu-based paddocks on all three farms are mulched every autumn and under-sown with Italian ryegrass.
Kikuyu pastures have proven to be highly resilient, with little plant death and a rapid recovery following Cyclone Gabrielle flooding in early 2023.
Most other pasture species, including ryegrass, tall fescue, cocksfoot, chicory and clovers, died as a result of the flooding and had to be resown.
In Focus Podcast: Full Show | 19 July
Bryan talks with Minister for Mental Health Matt Doocey about how the government plans to tackle the mental health crisis in rural communities. Doocey says local organisations are best placed to meet the needs of their communities and he outlines a new decentralised approach.
Bernadette Hunt from Federated Farmers in Southland also joins the studio, to discuss concerns about how sites and areas of significance to Māori are being categorised. She says farmers have no clue about how to identify specific sites on their land. Senior reporter Neal Wallace unpacks the challenges exporters face as some of our biggest trade partners embrace a more protectionist approach to trade. And, recent sales may be signalling a lift in farmgate returns for sheep and beef farmers.
