Sustainable Vegetable Systems Update No.8: Programme Update Q3 2nd year.

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Update No. 8 Sustainable Vegetable Systems (SVS)
Programme update, March 2022, Quarter 3, 2nd year.

Full report with data tables can be read here.

Workstream 1 – Controlled experimentation to quantify nitrate leaching

  • We have progressed the four rotations and are approaching the last crop, ryegrass, to be sown in Rotation 1 and 2 in Canterbury and Rotation 3 in Hawke’s Bay. Rotation 4 is entering cauliflower followed by a final crop of ryegrass.
  • Data collection and analysis is ongoing in this Workstream. Here we summarise preliminary data of crop N and changes in soil N within Rotations 1, 2 and 4. In terms of crop N, we are interested in key components that contribute to the N balance, such as crop N uptake and N content (N%).
  • In Rotation 1 (potato – wheat – broccoli), N uptake by harvested product increased for all crops except broccoli, which had no yield change with N rate. N residue also increased with N rate across all crops. The N% of the crops increased with N rate.
  • In Rotation 1, soil N increased rapidly in the top 15 cm after the broccoli crop and during the onion crop. This increase in soil N is partly due to mineralisation, but also a likely important contributor is the breakdown of broccoli residues.
  • A leaching event early during the wheat crop in Rotation 1 occurred before fertiliser was applied to this crop. Leaching was calculated as part of Workstream 3; averages were 15, 17, 21 and 42 kg N/ha leached for treatments N1, N2, N3 and N4 respectively. The differences between N treatments prior to fertiliser application suggest a legacy effect of N management in the previous crop. Importantly, there was leaching even in the N1 treatment, where no fertiliser was applied in the previous crop.
  • In Rotation 2 (pak choi – oats), N uptake in harvest product, residue N content and N% of the crop increased with N rate.
  • In contrast, in Rotation 3 (pak choy – lettuce) grown in Hawke’s Bay, N rate had no effect on N uptake in harvested product or residue, or on N% in either pak choi or lettuce. Soil N in the Rotation 3 had values close to 200 kg N/ha in the top 15 cm, compared to 100 kg N/ha in Rotation 2. This difference in soil N led to difference between the two pak choi crops.

 Workstream 2 – Regional on-farm monitoring

  • Monitoring continues at the 9 regional sites. Most sites finished the quarter in fallow or about to enter a fallow period. The regional monitoring sites crop rotations are shown above.
  • The splitting of soil samples between the commercial and Plant & Food Research laboratories for side-by-side comparison continued.
  • The regional monitors meet on the last Monday of the month, along with PFR, and covers H&S, progress update, and discusses any issues and ideas amongst the nationally dispersed monitoring group.
  • The individualised soil mineral nitrogen reports were updated and circulated to the monitor site growers. The nitrogen budget reports are waiting on further plant data.
  • The additional crop monitoring continued. This is to provide a more robust database on crop nitrogen concentrations and harvest weights. 27 potato samples were taken with the intention of developing a variety specific dataset. 6 green vegetable crop samples were collected. The vegetable crop sampling will continue to provide a regional and seasonal dataset.
  • It was identified that the monitoring sites do not include a winter grown potato crop in Auckland. An additional paddock has been added that is alongside an existing monitoring site. The same monthly sampling protocol is being followed from pre-planting through to the postharvest fallow period.

 Workstream 3 – Farmer facing tool(s)

  • Anne-Maree Jolly has been appointed as the WS3 leader alongside Hamish Brown. Anne-Maree brings her extensive knowledge from a soil science perspective along with a lot of nitrogen modelling experience while at Ballance and now WSP.
  • A significant step forward was the development of the tool prototype, tentatively named N-Sight.
  • Discussions are continuing with Overseer about collaboratively working together.

 Workstream 4 – Developing a change landscape

  • An SVS logo was created for use initially in the videos and podcasts but is now being used more widely in presentations and articles.
  • Preparation for a series of 3 videos is underway. These include:
    • Project introduction and overview
    • Case studies/monitor sites. Greater understanding of the nitrogen cycle.
    • Science story – trial sites to labs to modellers
  • Preparation for 6 podcasts. These are being recorded on the same day and will be distributed monthly. The topics are:
    • Why SVS?
    • Understanding the leaching problem (catchment perspective)
    • A nitrogen balance
    • A Nitrogen budget and tool prototype. N-Sight.
    • Regulatory landscape (possibly delayed)
    • What does good look like? 
  • SVS Updates generated from NZ Grower articles are sent to the growing email distribution list, are hosted on the Potatoes NZ website, linked to in product group newsletters and social media.
  • The Workstream 4 team began developing a Logic Model (below) for SVS as a halfway review step and giving direction to future dissemination.

Key highlights and achievement

  • The tool prototype (N-Sight) was developed. This is now ready for demonstrating to a wide range of audiences.
  • Mineral N tracking reports at a point where they are valuable tools that act as the basis for discussing mineral nitrogen flows. Used in the February NZ Grower article and in upcoming Tech. Panel meetings.
  • Development of the video and podcast series.
  • Collection of over 33 additional plant samples with the process continuing to build a more robust crop database. This also engaged more growers directly in the programme with the opportunity to describe SVS’s goals and giving them a stake in the outcome.
  • The collaborative development of the Logic Model by the Workstream 4 team and subsequent clarity around the dissemination plan.
  • Advancing the thinking on the tool implementation pathway options, issues, and opportunities. Culminating in the Special Project Governance Group meeting.
  • Preparation for grower, and supply and service industry interviews on the tool to be conducted in Q4.
  • Formalised contracted links into concurrent PFR projects on soil mineralisable N.
  • A new Workstream 3 leader – Anne-Maree Jolly (WSP) is now part of the programme.
  • Recruitment of people to join the Reference Group across growers, councils, suppliers, Overseer, and product group representatives.

Outcome Logic Model

Upcoming activities

  • Technical Panel workshop (2 days in 4 Zoom sessions)
  • Workstream 3 modelling meeting in Lincoln (24th May)
  • PGG meeting to discuss tool pathway options (1st April)
  • Rezare interviews, analysis, and draft report on SVS Tool implementation pathways
  • FOLKL grower, FAR, supplier and service industry interviews on the tool prototype
  • Ongoing monitoring, trials, and additional crop sampling
  • Reference Group first meeting (28th July tbc)
  • Formation of the Community of Practice
  • Incorporating plant analysis into a new individualised monitoring site report based around a nitrogen budget.
  • Grower initiated XLabs project using the SVS tool prototype N-Sight. XLabs is a proven capability – building program — here to accelerate the design, validation and progress of your circular solutions and innovations. Design sprint will take place from 23rd to 27th May.

SVS is funded by Ministry for Primary Industries, led and co-funded by Potatoes New Zealand in collaboration with the Vegetable Research & Innovation Board and Horticulture NZ.
SVS is a $7.5 million dollar national project over 4 years and is multi-workstream aimed at providing the data and subsequent modelling of vegetable nutrient uptake and nitrogen leaching.
Overall SVS programme aims:

  • To maintain vegetable and potato industries’ social license to operate
  • To protect the ability to grow, process and sell, while meeting environmental standards
  • To ensure industry access to land, water and nutrients through national, regional and farm programmes in order to achieve industry growth.

SVS Programme Communications

  • All SVS Updates here
  • SVS Report and background info here
  • The first SVS video here
  • The Quick N Test video here 

Ngā mihi nui,

from the SVS team.