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

One of the new strips, which is located under the irrigator wire, includes alyssum, calendula, and native ground covers. The other strip which is along a fenceline has the A Lighter Touch annual flower strip mix, which includes alyssum, buckwheat, calendula, cornflower, and marigolds. We also added in a few sunflowers.

The first half of the strip under the irrigator wire has established really well, and both the alyssum and calendula are starting to flower. At the other end of the strip, it is a bit patchy and doesn’t have the same ground cover. Some of the native ground covers amongst the strip have dried out or have been eaten by rabbits, while others are thriving.

The strip along the fenceline consists mainly of buckwheat and sunflowers at the moment, as they were the first to germinate. However, there are patches where alyssum, marigolds, cornflower, and calendulas have also started to establish.

The two biostrips planted in 2024 were made up of 9 different flower mixes, first planted in spring and the second in the summer.

The spring 2024 sowings flowered in the summer but were taken over by grass and clover in the winter. We have mown the strip a couple of times to manage the grass and give the flowers a chance to grow. The alyssum, poppies, borage, and phacelia seemed to do the best in spring 2025 after being mown. Now the strip is mainly grass, clover and alyssum. We have mown it back down again and will track what happens.

The strip planted in summer 2024 and has continued to flower since it was established. Alyssum is the main flower species that has taken over and provided ground cover, but there are areas where there are still cornflowers and calendulas flowering.

There are plenty of insects in the strips and within our butternut crop, but we wanted to understand what insects are actually there and how far they are moving into the crop. To do this, we have set up sticky traps within the biostrips and at various distances into the crop. We will continue to monitor the sticky traps and will try to identify what insects are on them.

We will be holding a grower biodiversity event at the MicroFarm on March 19th. If you are interested in attending, please register here: https://a-lighter-touch.co.nz/biodiversity-grower-group-field-walks/

The Conventional treatment was planted with treated seed and 300kg/ha of Complex fertiliser.

The Hybrid treatment was planted with treated seed, coated in TrichoStart and 300kg/ha of Complex fertiliser. Mycorrcin, Biostart N and TrichoStart were applied at planting via liquid injection.

The Regenerative treatment was planted with untreated seed, and 5kg/ha of humates mixed with 150kg of Complex fertiliser. As with the hybrid treatment, mycorrcin, Biostart N, and TrichoStart were applied via liquid injection.

After planting, all treatments received Ironmax slug bait before two 50cm strips of pre-emergeence herbicide, Frontier-P and Magister, were strip-sprayed over the plant lines.

Throughout the season, the Operations Advisory Group and Heinz-Wattie’s agronomists will meet weekly to track how the butternuts are growing. Together, they’ll make the calls on crop protection, weeding, fungicide and insecticide use, and adjust management decisions as the season unfolds.

A big thank you to Gareth Holder from Redloh Horticulture for taking the time to plant our butternuts.

Carbon Positive is a partnership between LandWISE, the HB Future Farming Trust, McCain Foods, Heinz-Wattie’s and Process Vegetables NZ.

In the 2025-2026 cropping season, the fourth summer of the Carbon Positive trial, we are growing butternut pumpkins for Heinz-Wattie’s. Our planned planting date is the middle of November.

In the Conventional system, things are getting underway with a broadcast spray of glyphosate now that the sheep have been moved out. The paddock will be cultivated in early November and planted with butternuts. Fertiliser applications, including planting and side-dressing, will be at full fertiliser rates that are typical on the Heretaunga Plains.

The Hybrid system was strip-sprayed in mid-September and will be strip-tilled about three weeks before planting. Two weeks before planting, it will be broadcast-sprayed to clean up the remaining cover crop outside the strip-sprayed zone. We may spray about three days after planting if weeds or cover crop regrowth are an issue. Fertiliser applications, including planting and side-dressing, will be guided by soil results.

The Regenerative system was also strip-sprayed in September, and the plan was to avoid cultivation. However, grazing sheep have compacted the soil, so strip-tilling is our back-up plan. Two weeks before planting, it will also be broadcast-sprayed to tidy up outside the strip sprayed zones. Glyphosate will be used to knock back the ryegrass, but clovers and vetch will be left as companion crops. As with the Hybrid system, a clean-up spray may be needed three days after planting. Fertiliser rates will be set according to soil test results.

We will determine weed management tactics as we go but are anticipating that a stale seedbed approach and favourable weather may do most of the work. Our strips will allow the precision weeder to operate if necessary, and there’s a manual fallback we prefer not to think about just yet!

Throughout the season, the Operations Advisory Group and Heinz-Wattie’s agronomists will meet weekly to track how the butternuts are growing. Together, they’ll make the calls on crop protection, weeding, fungicide and insecticide use, and adjust management decisions as the season unfolds.

We are particularly grateful to Heinz-Wattie’s, Gareth Holder from Redloh Horticulture and Hamish Thomas from NH Packing for their support. We look forward to working with them as our butternuts are sown, grown and harvested! Carbon Positive is a partnership between LandWISE, the HB Future Farming Trust, McCain Foods, Heinz-Wattie’s and Process Vegetables NZ.

Many thanks to our sponsors

With funding from Te Ahikawariki, we teamed up with regional agronomists to ask a number of growers about cover cropping. We wanted to learn what the barriers were to new entrants, and what the ongoing headaches were for those who do use cover crops.

Three-quarters of the 32 growers surveyed have been using cover crops for an average of 23 years. These aren’t beginners struggling with basics—these are people who’ve figured out how to make cover crops profitable, and their insights challenge everything we think we know about adoption barriers.

We were perhaps not too surprised to find the barriers everyone assumes matter most actually don’t. Equipment access scored just 1.2 out of 4 as a barrier—the lowest of everything measured. Information gaps scored only 1.6. These experienced growers have moved way beyond those basic issues.

So what are the real barriers? Three big ones that actually matter:

1. Nitrogen Tie-Up (The Technical Killer)

Cover crops locking up nutrients when your cash crop desperately needs them. This scored 2.7 out of 4—the highest barrier measured. It’s not about getting cover crops established; it’s about managing what happens to your nitrogen afterward.

2. Weed Management Gone Wrong

Getting effective suppression without creating new problems. Too often, cover crops become part of the weed problem themselves rather than solving it.

3. Operational Flexibility (The Hidden Killer)

This one was not even in our list of questions but came through loud and clear in grower comments. As a Hawke’s Bay grower put it:

“Once land is cover cropped it ties it up for a period of time and if it’s a wet season then it reduces options and we can fall behind in our planting programme.”

It’s about losing the ability to adapt when weather doesn’t cooperate. That’s a fundamental farming system challenge, not a technical problem you can solve with research.

Why Three-Quarters of These Growers Persist

Despite the barriers, 75% of surveyed growers use cover crops. What’s driving them?

Soil structure improvement absolutely dominates. It scored 3.4 out of 4, with 87% rating it as highly important. Half called it “make-or-break” for their decision.

One Pukekohe grower explained: “The difference in soil workability after a few years of cover crops is dramatic—better water infiltration, easier cultivation, improved root penetration.”

Interestingly, environmental benefits come second. Biodiversity enhancement, soil moisture management, input reduction—they all scored well, but practical farming benefits drive adoption more than environmental ideals. These growers are businesspeople first.

Species That Work (And the Ones to Run From)

After 23 years of collective experience, some clear winners and losers have emerged:

The Champions:

• Oats: Top the list for reliable establishment, easy termination, good biomass production
• Annual ryegrass: Consistent cover, works with livestock
• Vetch: Nitrogen fixation benefits

The Problem Children:

Multiple growers warned about rye—”potential to become a weed” and “difficult to remove.” Brassicas got harsh verdicts too, especially near seed crops. One grower’s blunt assessment: “Radish is a strict no no” because of contamination risks.

And those complex multi-species mixes everyone talks about? “Hard to manage and control weeds” was the verdict. The experienced growers say start simple, learn the basics, then add complexity gradually. Seed crop contamination is huge here because of our export industry. You can’t afford volunteers in the wrong places.

Land tenure creates headaches too. Landlords want to graze cover crops for income while growers want maximum biomass for soil benefits. As one frustrated grower explained:

“When cover crops are grazed we see little benefit especially over a wet period as we need more cultivation and have worse soil structure.”

These aren’t technical problems you can research your way out of—they’re structural issues that need policy solutions.

We’re Not Alone in This

The good news? Remarkably similar patterns show up internationally. US research confirms soil health is the primary driver globally—87% internationally versus our 87.5%. The same technical challenges around nitrogen management and termination timing appear everywhere. We’re not unique in our barriers, which means we can learn from solutions developed overseas.

Getting Started: Advice from the Trenches

What’s the advice for growers considering cover crops? Start simple. Pick one reliable species like oats. Begin on less critical paddocks. Most importantly, plan your termination method before you plant—that’s where many beginners fail. Expect a learning curve. One Canterbury grower with 15 years’ experience captured it perfectly:

“The first year taught me what not to do. The second year taught me what might work. By the third year, I started to see why everyone talks about soil structure benefits.”

At the bottom of this post you can download a link to a report by Charles “Merf” Merfield. We asked him to put his experience and thoughts on paper for all to see. It’s well worth your time to read. In brief, Merf says:

Simply put, cover crops are plants you grow for reasons other than selling them. Think of them as your farm’s support crew—they’re not the stars of the show, but they make everything else work better. That’s why they’re increasingly called “service crops” overseas, which honestly makes a lot more sense when you think about it. These aren’t exotic plants we’re talking about. Most cover crops use the same species you already know well—oats, ryecorn, mustards, clovers, and annual ryegrass. The difference is how and why you’re using them.

Cover crops aren’t a one-size-fits-all solution—they’re more like a Swiss Army knife with different tools for different jobs. Green manures are all about fixing nitrogen from the air using legumes. Catch crops are your nutrient insurance policy. Mulch crops suppress weeds better than most herbicides. Smother crops actually smother established problem weeds, think of them as your biological bulldozer. Then there are the conservation biocontrol crops—plants that support beneficial insects to keep pest populations in check.

The Cost Reality

Seed costs are real—they scored 2.5 out of 4 as a barrier. But the bigger challenge is demonstrating long-term value. One grower captured the economic puzzle: “How to put a value/dollar on them, especially longer term benefits.” The benefits take 2-3 years to become obvious, so you need patience and persistence.

Thanks to Daniel Sutton for initiating this research, and the regional agronomists who helped interview growers; Andrew Luxmoore in Pukekohe, Chris Lambert in Gisborne, Dan in Hawke’s Bay, Karen Coleman in Manawatu/Levin and Charles Merfield in Canterbury. And thanks, as always to the growers who gave time to share their experiences and knowledge.

Download the Full Cover Crops Survey Report

Download a supplementary report by Charles Merfield

The cover crops were direct drilled by Kettle Contracting on the 7^th of April. The Conventional treatment was planted with Moata annual ryegrass. The Hybrid treatment also has Moata with crimson and Balansa clover added. The Regenerative treatment has the same cover crop mix as the Hybrid treatment with the addition of vetch. As in previous years, the Conventional treatment will be grazed by sheep over the winter, while the Regenerative and Hybrid treatments will not.

In the chart above, the last two measurements are artificially lower than the actual covers. The Canopeo app has difficulty identifying deep shadow in bright sunshine conditions. We would expect all treatments to be very close to 100% ground cover if images were collected on a cloudy day.

The cover crops established well, with all treatments nearly reaching full canopy cover after 8 weeks. This is an improvement from last year’s cover crops, when the Hybrid and Regenerative treatments struggled to reach full canopy cover before termination.

A key difference in 2025 is that the regenerative treatment has been planted with ryegrass and three legumes, rather than multispecies mixes with oats, radishes, sunflowers, buckwheat, vetch and clovers. One reason for this is the get maximum ground cover as quickly as possible at a manageable cost. The multispecies mixes took a long time to reach 80% ground cover in 2024, and never fully covered the ground. Seed rates could have been increased, but costs were already high compared to annual ryegrass.

The 2024 ground cover chart shows the difference between the annual ryegrass (yellow line) and the multispecies (blue and green lines) cover crop growth rates. Gaps in the Hybrid and Regenerative plot covers allowed weeds to emerge but still did not cover all the soil. (The weekly dips are caused by the bright sun image analysis issue noted above.) The Conventional ryegrass was sprayed out early for process peas, hence the drop from early July. The multispecies cover crop in the Hybrid (blue line) was sprayed out later, also for peas. The Regenerative treatment (green line) stayed high because the cover crop was retained, rather than growing a pea crop.

What is next?

The 2025-2026 summer crop is butternuts for Heinz-Wattie’s, with a mid-November planting date expected. This gives a lot of time for any cover crop benefits to be captured and raises the possibility of a second crop in spring if desired. The Carbon Positive Operations Advisory Group will meet in July to confirm management plans for each treatment.

Carbon Positive Field Walks

We hold regular open field walks for our community to visit the Carbon Positive research plots, hear updates and contribute to future plans. Our email LandWISE Updates give details – sign up to receive notifications.

LandWISE Events Archive

Others’ Events

Merfield Agronomy Physical and Ecological Weed Management Workshop

Tuesday 22 July 2025, Waimate, Canterbury 

Learn about the latest in mechanical weeding and how to integrate that and herbicides in this one-day workshop.  Hard registration deadline is Friday 4th July. 

NZAPI EXPO 2025 – New Zealand Apples & Pears

30 July – 1 August – Nelson

2025 NZPPS Symposium – “Resistance Management – Today’s Tools for Tomorrow”

11 August, Christchurch

NZPPS Conference 2025

12-14 August, Christchurch

Potatoes NZ Conference

12-13 August 2025, Christchurch

New Zealand Horticulture Conferences 2025

26-27 August, Wellington

NZARM 2025 Changing Landscapes

11 – 13 November – Blenheim Marlborough

Getting to Carbon Positive

Wednesday 21 – Thursday 22 May
Havelock North Function Centre

In 2025 we’re delighted to bring you a conference with focuses on regenerative crop production, carbon footprinting, and electrification. We’ll have new technologies to think about and see, we have speakers with proven track records, and we’re looking forward to catching up with old friends and new.

Do we know the footprint of our activities? How do international markets assess them and what will we need to report? We are proud to present Associate Professor Dr Pii-Tuulia Nikula to open the managing our footprints conversation. We’ve done the numbers on our Carbon Positive cropping treatments, and we’ve others talking about what they are doing to address their footprints too.

If we are going to get to Carbon Zero (or better) we need to think about both inputs and outputs from our systems. Can we soak up more than we lose? Which inputs have the greatest impact?

We will report on progress and lessons from another year of our regenerative cropping research and present some new tools for growers to assess nitrate levels and soil stability. We’ll have examples for viewing at the Horizons Regional Council Field Session. Others will update us about new technologies for pest and disease control and reintroducing insects to cyclone impacted orchards and discuss the use of bio-strips and insectaries to encourage beneficial insects.

We’ll need energy, of course, but how much can we generate on-site? Is electrification realistic now? Where to in the short to medium term? We are delighted to have Mike Casey of the Electric Cherry Orchard and CEO of Rewiring Aotearoa opening the discussion on electrification and alternative energy case studies. We’ll have electric vehicles for perusal.

Thanks to our Sponsors!

We look forward to seeing many of you again in 2025.

Being able to see the biodiversity strips, native plant pods (insectaries), and cover crops that are a part of “A Lighter Touch”, then hearing about the differences they are seeing with all three working together was a highlight for me. LandWISE also has native insectaries and has planted biodiversity strips alongside our annual cover crops. It was interesting to hear Howe (Balle Brothers’ crop manager) talk about how he expected they would have to spray an insecticide due to an increased number of aphids. However, they left it for two weeks, and the aphid numbers dropped as the beneficial insects controlled the aphid population without the need for insecticides.

Water quality was a major topic of conversation in many courses I did at university. Therefore, it was very interesting to hear about the cultural indicator tool for water quality monitoring. It is used in evaluating the current state of waterways, as well as determining actions needed to improve the water quality. For me this talk also reinforced how important it is for Mātauranga Māori and science to be integrated.

I also enjoyed listening to the career session for students. It was interesting to hear how everyone ended up in horticulture and why they enjoy it. I particularly liked hearing about the experiences and successes of other young women in the industry.

Thank you, Vegetable Industry Centre of Excellence (VICE), for hosting the Vegetables Big Day Out. It was great to be able to attend such an insightful and interactive event. I would also like to say thank you for giving me a VICE internship, as part of which I will be doing Slakes aggregate stability testing and nitrate testing with a Nitrachek device.

Two suggested approaches for increasing biodiversity caught our attention. Over the last six months, we have been exploring their implementation at the MicroFarm. We are enormously grateful to Olivia Prouse for supporting our biodiversity journey so far. We are also grateful to Richard Mills from Summerfruit NZ for leading the way in Hawke’s Bay, and showing us the importance of just giving something a go! We also extend our gratitude to other growers engaging in this initiative, who have been sharing their experiences.

Mobile Insectaries

Mobile insectaries (moveable pods) aim to provide a source of shelter, nectar, alternative hosts and pollen (SNAP) for beneficial insects. The concentrated areas of SNAP support natural enemies, which can aid in pest control in vegetable crops. The moveable pods can be moved in and out of crops easily during the year.

Following the detailed ‘how to’ guide provided by ALT, with additional support from Olivia Prouse for plant selection, we built four moveable pods. Each pod has native five plants, all selected to flower at different times of the year. The species selected were mainly plants that had small flowers to provide habitat to small predatory wasps and other small insects which cannot feed on large flowers like commonly grown manuka.

We have been monitoring the pods to see what is flowering each month. While there is some maintenance required for weeding and watering, all plants survived the winter and are thriving this spring. We are excited to have species like Pimelea mimosa, which is a native daphne, naturally found only on Te Mata peak, and to have two species of Muehlenbeckia, which provides a food source for NZ native copper butterfly.

Annual Flower Strips

The aim adding annual flowering strips to a farm is to enhance above ground diversity. Again, this increases the diversity of natural pest insect enemies, providing additional pest control.

At the MicroFarm, we had two specific areas that made for good candidates for annual planting strips. The first is along our driveway, an area which is normally sprayed year-round for weeds. The second is under the irrigator guide cable, another area that gets sprayed, particularly in the spring and summer when the irrigator is running.

Using the ‘how to’ guide from ALT, we have planted a variety of annual flowers in these areas to see what might be suitable. In late September, we planted nine 10 m long plots of annual flowers, each with different combinations of species planted. The rest will planted by early December. We have been monitoring what is growing and what is flowering, and are excited to see insects present and a range of different colored flowers along the driveway.

What’s next?

We continue to monitor the moveable pods and annual flowering strips. We hope that our late plantings will persist through the summer and autumn. While not formally part of our main Carbon Positive project, it is a nice supplementary demonstration. We hope to showcase the ALT guides and provide some regional information about what may be suitable to grow (annuals and perennials) here in Hawke’s Bay. Read more about our journey in the latest A Lighter Touch newsletter here!