What has been happening over Winter?

Things have been a little quiet over the last few months. We’ve had our usual regular monitoring tasks, tracking cover crop development with the Canopeo app and soil nitrate levels with the Nitrate Quick Test protocol, Nitrachek device and our conversions to kg/ha. Now we are focusing on getting ready for our summer crop – food quality maize with Nicolle Maize.

We fully discuss the winter cover crop in an earlier post, but in essence, triticale and vetch took off more strongly than annual ryegrass but were overtaken in mid-July after aerating through fill cover and as the triticale was affected by rust. Generally, we are happy with the covers but think growth may be a little less than previous winters. The vetch this year was a standout success after a few years of disappointment.

The free nitrate in the soil has been very low all winter. The chart below tracks the nitrate in the top 30 cm of soil since cover crop establishment. Note this is twice the standard sampling depth.

After being the lowest treatment from mid-April to mid-June, the Regenerative triticale and vetch plots showed a jump and have remained higher (although still very low) than the Conventional and Hybrid ryegrass plots. Is there a link with the canopy cover levels? If the vetch starting to release free nitrate from the nodules?

No fertiliser was added at planting, so the increase in April is assumed to be the result of mineralisation after the butternut crop was harvested and the plots disced and planted. As the cover crops established, they appear to have taken up nitrate although significant rain from 18-21 April may have had some influence.

Soil moisture measured by Hydrosense or oven drying shows no differences between any of the treatments.

Outreach

We had a few opportunities to talk about the Carbon Positive trial over winter. Notable events were taking part in Lincoln University’s State of the Land Event “Regenerative Agriculture in NZ Landscapes: From Practice to Evidence” at which Dan presented the mid-project soil carbon results and use of AI to develop a model to explain changes in and within the various carbon pools. Notably, the emerging science around photosynthates as a key driver of soil carbon suggests the significant fallow and low ground cover typical of an intensive vegetable growing programme is a major block to nett carbon sequestration.

What can we do about that? We think strip-spraying and strip-tillage is one approach. Not only does it retain actively growing (photosynthesising) plants as long as possible, strip-till also minimises tillage – a major cause of carbon burn-off. Several LandWISE Conference presentations addressed this, and the videos have been uploaded to the website.

Another technique would be getting a cover crop growing within the main crop, so that after harvest, it is already growing an “catching some rays”. This however might be a little trickier. Numerous attempts have been made by numerous groups in numerous places and results have been varied. But our Operations Advisory Group is keen that we have a goo. So, we are looking at establishing some legumes in the maize this summer, but leaving sowing until as late as possible to minimise the risk and scale of competition with the money earning maize.

Dan was also asked to present to the annual ICD Group conference. He introduced LandWISE and our history from our roots in wind erosion minimisation, through strip-till, autosteer, precision ag and various nitrate minimisation projects. It was a good opportunity to reflect on 25 or so years on LandWISE activity. While immensely varied, the focus throughout has been on sustainable production through technology and system choice. We have a large legacy of work in soil health, optimal nutrient management and making the best possible use of scare water resources. If you haven’t already, have a look at the various tools and calculators and the online learning courses on our website.

Dr. Charlie White is a faculty member at Penn State University, specializing in soil nutrient behavior and management.

He has taught various courses, including Soil Nutrient Behavior and Management, Internship, Independent Studies, Thesis Research, and Supervised Experience in College Teaching.

His research focuses on sustainable agricultural systems, biogeochemical cycles, and nutrient management to promote productive and efficient nutrient use in cropping systems.

In this presentation, Charlie will share some of the key insights into managing cover crops for nutrient management and soil health that he has learned through twenty years of research, much of it conducted in partnership with farmers in the temperate, humid climate of the Mid-Atlantic USA.

These lessons include the importance of measuring and managing cover crop and soil organic matter carbon, nitrogen, and C:N ratios to balance nitrogen retention and supply; that a little bit of grass in a cover crop mixture goes a long way to reducing N leaching; and that a cover crop mixture with balanced species proportions will be the most multifunctional, but achieving evenness in the biomass is easier said than done.

Finally, Charlie will return to his roots in reflecting on the importance of mycorrhizal fungi to the phosphorus nutrition of crops, and why P stratification in no-till system may not be as much of a problem as we think because of these symbiotic organisms.

Session Synopsis

Growing multiple vegetable crops across a farming operation the size of Harvest Moon requires constant decision-making, careful timing and a deep understanding of what crops need at every stage of growth. In this session, Josh will walk through how Harvest Moon manages nutrient applications across more than a dozen crops using a combination of field experience, soil and sap testing, and modern data tools.

He will explain how the team schedules and calculates nutrient inputs throughout the season, how they identify inefficiencies in the system, and how these insights feed into broader Integrated Pest Management strategies. By continually measuring and refining what happens in the field, Harvest Moon is able to reduce risk, improve crop health and optimise yield.

The session offers practical, real-world insights for growers looking to sharpen their nutrient strategies, improve efficiency and get more value from the data already available in their farming systems.

Sponsored by

Dr Sally Anderson is the Scientific Services Manager for Market Access Solutionz Ltd and is based in Wellington. Sally has over 15 years’ experience designing, managing, and implementing science research programmes for New Zealand’s horticultural sector. This includes co-ordinating the Vegetable Research & Innovation Board, managing Summerfruit, Citrus and Onions R&D programmes.

Sally has a science background and holds a and PhD from the University of Auckland, with over 10 years of research experience in environmental ecology, molecular biology, and microbial ecology, with prior roles at NIWA (now Earth Sciences NZ) and the Wellington School of Medicine.

Leading the science services portfolio at MAS, Sally works to support clients with technical advice in plant health research, biosecurity, crop protection, export market access.

As the Vegetable Research & Innovation Board co-ordinator, Sally worked alongside industry stakeholders to secure funding from MPI NIWE fund to support the vegetable, fruit and arable sectors to carry out monitoring post-Cyclone Gabrielle to better understand how highly productive land recovers from these extreme weather events. These learnings and those from other agencies were showcased at the Cyclone Gabrielle Research Symposium, held on the 19-20^th November 2025. Sally will summarise the symposium and its findings.

Katherine Martin is a consultant at Perrin Ag, working across agronomy, farm systems, and environmental planning to support growers in improving productivity and strengthening environmental outcomes. Her work spans vegetable and pastoral systems, with a strong focus on soil health and regenerative practices at the paddock scale, alongside translating research into practical, farm‑ready insights for growers.

Intensive vegetable systems often leave soil bare between crops leading to nitrogen leaching and soil erosion. Crop stacking offers an innovative approach keeping living ground cover in place for the months that would otherwise be fallow.

After harvest, a “sentinel” cover crop is established, once the cover crop is established, narrow planting strips are selectively sprayed to plant the commercial crop into. The cover crop is left in place during early commercial crop establishment; the cover crop is desiccated two to three weeks later to avoid it outcompeting the commercial crop.

This presentation shares findings from a three‑year programme (2023–2025) testing crop stacking in a commercial broccolini system in Pukekohe. Across multiple seasons, crop stacking consistently reduced the risk of nitrogen loss, by up to 31%, and resulted in lower levels of mineral nitrogen moving deep into the soil profile. Trials also showed strong early crop establishment, increased yields, and noticeably less soil erosion.  Together, the results show that crop stacking can deliver real environmental gains with the potential to increase productivity.

We were delighted to host Vicky Bloomer from Drop Consulting to present the Irrigation New Zealand Performance Assessor training course at the Centre for Land and Water this week. And what a wet week it was, so we thank them for breaking the drought in this part of the country.

The course participants were out and about visiting Drumpeel Farms to assess a centre pivot, our neighbours YummyFruit to assess drip/micro system and an Oderings nursery to look at a solid set system. At the LandWISE MicroFarm, they assessed the linear move irrigator. LandWISE Project manager Olivia Webster is one of the course participants

The performance assessment course is based on the Irrigation New Zealand Piped Irrigation System Performance Assessment Code of Practice, initially developed by Dan Bloomer at Page Bloomer Associates. The concept of irrigation performance assessment was strongly promoted by Hugh Ritchie following his Nuffield scholar experiences in the USA and he was a key player in obtaining funding support to write the New Zealand codes in the first place.

The MicroFarm Linear

The LandWISE linear machine was donated by Hugh and Sharon Ritchie. It was converted to a low energy precision application system (LEPA) by WaterForce who have been excellent with anything water related we need. The machine began life as a 460m multi-span linear at Drumpeel, and when it was due for replacement, Hugh collected the best bits and rebuilt it to fit the LandWISE MicroFarm. In its early days, it was repeatedly measured as a test case while the Code of Practice was developed! It was also used in other SFF projects assessing impacts of application intensity of soil surface redistribution and consequent soil moisture uniformity.

Quinn Elstone at WaterForce deigned the LEPA system specifically for the MicroFarm layout, centring the outlets above each 2m bed. We run two parallel header pipes along the linear span, and we can split the sprinklers between them. We can use the sprinklers as rotators doing a wide overlapping ~12m spread to maximise uniformity and minimise application intensity. Or we can run them as sprays with a 5m spread, keeping application tighter to our 12m plots. A third option is changing the nozzles to tighter 2m splash plates that water each bed individually. Or we can turn individual nozzles off.

Images of irrigator showing 12m spread rotators on left, 2m splash plates in centre and 5m sprays at right

Why LEPA?

It gives us tremendous flexibility.

In the LEPA system the nozzles are very close to the ground, so we see very little effect in windier conditions. And because we generally run the irrigation during the day to take advantage of our solar electricity system for pumping, there is often a bit more breeze than at night. We haven’t converted the machine from diesel yet – that is on a long list!

We can tailor irrigation to treatments.

In our Carbon Positive trial, we’re running 6 beds per treatment plot, and sometimes we want to do different things to different treatments. When the nozzles are running as sprays, there is very little overpal of treatments.

The WaterForce LEPA system lets us turn one treatment plot off and irrigate the other two, or irrigate only one plot. We can run nutrient solution in one header and fresh water in the other and fertigate some plots and not others, even though we have three different treatments under the irrigator at any time. For us, the Drumpeel/WaterForce machine has been life changing because without flexible high-quality irrigation, our trial work is severely impacted.

We are tremendously grateful to the Ritchies for the generous donation, and to WaterForce for their supply and installation of the components. It is this kind of community support that characterises LandWISE and has allowed it to be a success.

LandWISE Conference 2026

Havelock North Function Centre
27 – 28 May 2026

Our “Soil Health for Profit” theme in 2026 is, in some ways, a return to the past. LandWISE arose out of work to combat soil erosion through use of minimum tillage and we’re returning to strip-till in 2026. A lot has been learned in the intervening years! Along with that, we’ll look at what can be done to measure and manage crop nutrition and soil health to ensure sustainability and long-term profitability.  

We have international speakers from Pennsylvania and Tasmania complementing national and local growers and experts. They will share how they set out to build profitable enterprises with a focus on soil health and an eye to wider sustainability ambitions. We’ve asked them to offer ideas of things to take home and apply or try – to feed the appetites of keen delegates.

We have talks from people applying regenerative principles in cropping, pastures and orcharding, talks on strip-till and crop-stacking, soil amendments and cover cropping, and managing and minimising the cost of nutrients. As always, expect representation of agritech covering a wide range of technologies.

Remember to sign up to get updates!

See earlier posts:
Biodiversity Strips Update – LandWISE – Promoting sustainable land management

MicroFarm Biodiversity Update – LandWISE – Promoting sustainable land management

Lessons for the management of highly productive land

Two years after Cyclone Gabrielle devastated the Hawke’s Bay and Tairawhiti regions, what have we learned about recovery?

Cyclone Gabrielle struck New Zealand in February 2023, causing widespread flooding that affected Hawke’s Bay, Gisborne/Tairawhiti, and Northland. In Hawke’s Bay and Tairawhiti, Cyclone Gabrielle was characterised by the enormous amount of sediment that was deposited on some of the county’s most highly productive land.

It was an extraordinarily difficult year characterised not by a single catastrophic event but by cumulative impacts from severe storms and several additional weather events including Cyclone Hale in January, Cyclone Gabrielle and Son of Gabrielle in February, and others that followed particularly in the Wairoa and Tairawhiti areas.

In November 2025, we co-hosted with FAR and Vegetable Research and Innovation, a symposium for researchers to share and compare findings from studies of Cyclone Gabrielle and recovery. Around 60 people gathered in Havelock North for two days. Thank you to all the organisations that sponsored the symposium, allowing it to be run with no fees for the participants.

A great deal of semi-coordinated activity followed in the wake of Cyclone Gabrielle. However, there was much incomplete work that would add value by helping enrich our understanding of the longer-term effects of different management responses in different scenarios. The symposium brought together those who investigated Cyclone Gabrielle’s impacts on highly productive land. They presented and discussed findings and observations to draw out lessons to aid land managers and policy makers in future events.

Among the questions were:

1. What are the lessons to pass on to those impacted by future events?
2. What are the lessons for policy makers?
3. What are the economic outcomes from different approaches?
4. How have sites responded to different management of cropping soils, given different sediment types and depths?
5. How have sites responded to the removal of sediment and any subsequent soil amelioration efforts?
6. Have permanent crops responded differently to different approaches applied in similar scenarios?
7. Are all soils recovering quickly? Will they return to previous productivity levels?

Twenty presentations covered historic storm events of note, the weather conditions before and during the cyclone, geological influences, immediate responses, food safety, and longer-term trials seeking to understand how best to return high value land to best production. We thank all the presenters for telling their stories, and all delegates for their contributions to the discussion.

At the end of the symposium, Dirk Wallace led a feedback session in which all delegates responded to a set of questions:

1. What elements aided recovery and what lessons can inform policy and sector planning?
2. What surprises and challenges emerged during recovery?
3. What key takeaways should guide future preparedness?
4. What information is still missing?

Across questions, several themes consistently emerged.

• Communication and collaboration were identified as critically important.
• Data and research surfaced as both a strength and a challenge.
• Infrastructure and preparedness were recurring concerns.
• On the technical front, soil and crop recovery exceeded expectations, with yields rebounding faster than anticipated.
• Finally, human and social dimensions were central to recovery success. Mental health support, patience, and direct communication with experienced peers were repeatedly stressed.

Participants agreed on several priority actions:

1. Establish a central information hub with regional portals to provide consistent, accessible guidance and data.
2. Commission targeted research on rainfall patterns, soil microbiology, contamination risks, and crop-specific recovery timelines, delivered in decision-ready formats.
3. Strengthen pre-event coordination through drills, contact lists, and local decision-making authority, alongside investment in backup infrastructure.
4. Embed human-first supports, including mental health services, peer advisory panels, and tailored financial relief for vulnerable growers.
5. Integrate disaster risk reduction and nature-based solutions (e.g., wetlands, “room for rivers”) into long-term land-use planning.

The symposium captured invaluable knowledge that will help communities and policymakers prepare for and respond to future events. Visit the Cyclone Gabrielle Research Symposium page to access all presentations, with videos coming soon.

Thanks everyone! Sally Anderson, Dirk Wallace and Dan Bloomer – Symposium Convenors

In November, we co-hosted a research symposium with Vegetable Research and Innovation and the Foundation for Arable Research. The symposium brought together those who had investigated Cyclone Gabrielle’s impacts on highly productive land to present and discuss findings and observations, and draw out lessons to aid land managers and policy makers in future events.

A great deal of semi-coordinated activity followed in the wake of Cyclone Gabrielle. However, there was much incomplete work that would add value by helping enrich our understanding of the longer-term effects of different management responses in different scenarios.

The symposium brought together researchers, advisors, farmers/growers and others involved in observing the impacts on productive land and the effects of different responses in the cases of Cyclone Gabrielle and previous similar events. More than 20 presentations covered historic events, the broader climate context of Cyclone Gabrielle, a range of land use types and many areas of research.

The convenors (Sally Anderson, Dirk Wallace and Dan Bloomer) are now in the process of collating the proceedings and preparing to load material on the conference web page. We’ll do posts as items are loaded with abstracts, summaries and presentation videos. From the outset, the response to the calamity that was Cyclone Gabrielle has been one of high support and collegiality from many, many quarters. The symposium was our attempt to get the best from all the work that was done and find the lessons for those impacted by future events.

We are most grateful for the support and enthusiastic involvement of all the presenters and delegates and the organisations that funded the event.