Reducing Nitrate Leaching, Athol and Jane New (Canterbury)
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3 min read
Mayview farm has that modernised its irrigation system and actively works on environmental sustainability. Farmer Athol New is keen to share learnings and implement the latest sustainability practices. The farm spans 356 hectares and runs on a 3.5 cows/ha system. They've invested in bucket tests and irrigation scheduling to optimise water use, and introduced pasture renewal techniques. In the future, they're considering fixed grid installation, EM soil mapping, adding more soil moisture meters, and adjusting their nitrogen fertiliser usage. They're committed to reducing their nitrogen loss, currently at 57 kgN/ha/yr.
Mayview was converted in 2016 and purchased by the current partnership in July 2019.
The farm has a modern complex irrigation system including 8 pivots (2 with VRI) and some k-lines, which Athol is working to optimise through bucket testing and irrigation scheduling so that their N losses will be further reduced.
We wanted to be a part of the Meeting a Sustainable Future project so that we could both share the learnings we’ve had at Mayview, and to be able to access the latest information coming from research and other farmers putting mitigations into practice”
- Athol New, Mayview
Farm information
Area
347 ha milking platform, total 356 ha
Soils
89% Lism 1a.1 and 11% Lism 2a.1 soil type average PAW0-60 82 mm
Farm system
3.5 cows/ha, 15.8 tDM/ha pasture harvested
Irrigation
87% pivots, 10% k-line, 3% dryland
Relevant Features
- Modern and complex irrigation system with 8 pivots, including VRI
Mitigations to reduce environmental impact
Mayview is working to reduce their environmental impact to meet requirements and ensure they are running a sustainable business.
Mitigations implemented to date
Bucket tests
Tests were completed on all the pivots in the first season. “The range in performance was surprising, given the farm is quite new,” says Athol. “We replaced a number of sprinklers and have a plan to renozzle two entire pivots over winter. This should improve our uniformity and will also let us increase from 4 to 5mm/day through these two pivots, which will mean our water is used more efficiently. I’d recommend anyone who hasn’t done so do a bucket test, as it’s likely there are some easy wins that will both reduce any drainage you may be causing, and reduce the total amount of water you need to apply.”
Irrigation scheduling
Four soil moisture meters are already installed, and these are used to provide information on irrigation scheduling. By looking at what the monitors were showing, and what was actually happening out on farm, Athol was able to pick up that all of the moisture meters needed some refining for where the trigger points were shown. He says, “now that we have the graphs showing correctly, it’s going to make it a lot easier to share how we make irrigation decisions with the team and upskill them.”
Pasture Renewal
Paddocks are mostly direct drilled unless a specific need to cultivate is identified. 3kg/ha of plantain is now also being added to seed mixes to
Future mitigations
Fixed Grid Installation
Mayview considered replacing some k-line area with fixed grid. Athol has had this quoted, but the price was higher than the business was willing to pay given the impact both financially and environmentally that the change would make. While it hasn’t been ruled out, at this stage there is no immediate plan to make the change.
EM Soil Mapping
Having now had a season at Mayview, Athol has identified an area of the farm where it is likely that SMaps hasn’t correctly identified a heavier soil.
“We have in the medium term a plan to get the farm EM mapped, this way we can adjust the management of this area as it’s under one of the VRI pivots. It would also mean we can have the soil recognised in Overseer. I’ve talked to the neighbour on the boundary and they also find that this area seems to have more water holding capacity than how it is labelled in SMaps.”
Soil Moisture Meters
Four soil moisture meters are already installed at Mayview and having one under each pivot is where the farm is headed. Each pivot can then be managed with more accuracy, and Athol and the team can have more confidence that they’re not causing unnecessary drainage events.
Nitrogen fertiliser use
The plan for Mayview had been to target 200 kgN/ha/yr nitrogen fertiliser for the 2019/20 season, but the final figure was 260 kgN/ha/yr. “We had two unexpected events where we used nitrogen fertiliser as a tool to increase our feed available. The first was when the Barrhill Chertsey Irrigation river take was flooded in December, and we were unable to irrigation over a key 5 day period – our growth was impacted, and we needed to ensure we could catch up quickly. The second was when we were unable to get cull cows away over autumn due to Covid-19, and so we had more feed demand than usual. We are confident that we will be able to make tweaks to our current system and be able to operate within the new regulations.”
N Loss Progress
Current (2019/20): 57 kgN/ha/yr
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