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.

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.

Register now – Earlybird tickets still available

The winter cover crops in the Carbon Positive trial plots are well underway now. The last dull, wet, cold week slowed them down a little, but they still made good progress. The preparation and planting was covered in an earlier post that you can see here>

To the left of the central irrigator strip, the Regenerative plot triticale and vetch established fastest and by April 20 had reached 28% ground cover as measured using Canopeo, a brilliant free app that we use for all our weekly assessments regardless of crop (or fallow!). By contract, the ryegrass was slower to get started and on April 20 the Conventional plots averaged 5% ground cover, and the Hybrid plots a little more at about 8% cover as seen in the chart below. As well as getting underway quicker, the triticale and vetch is accelerating away. We had expected the ryegrass to be fastest, as that was what we observed in previous winter cover mixes, but a higher sowing rate of vetch and the triticale seems to be a good option at this stage.

There is some banding in the plots that seems to be an artefact of planting, but we’re not sure why. It lines up exactly on the planter but may relate to the discing and rolling that happened prior.

We continue our weekly monitoring, and assume that by next week, the Regenerative plots will have crossed the magical, but arbitrary, 30% ground cover faction. How long before the ryegrass plots reach that milestone?

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!

Register at Humanatix

All three treatments were then disced twice. Since the ground was so hard and dry, the first pass with the discs was quite blocky, but after the second pass, there were plenty of fines for a seedbed.

The Conventional and Hybrid treatments were both planted with Moata ryegrass (25 kg/ha). The Regenerative treatment was planted with triticale (80 kg/ha) and vetch (50 kg/ha). Butternut residue made drilling tricky as long “ropes” of dried vine blocked equipment. The hard, dry, rubbly surface in areas such as wheel tracks left seed above the ideal soil mix. Normally we would aerate as the last autumn operation, leaving the soil fractured over winter and spring. We think the butternut residue will make that extremely difficult, so have postponed it. If the soil is still dry enough once residues have rotted, we can aerate in a couple of months.

Thank you to Mike Kettle Contracting for doing our groundwork and planting our cover crops.

Because the soil is so dry, and with no rain on the Hawke’s Bay horizon, we are applying 12 mm of irrigation to ensure good establishment. Once complete, we plan to apply bait as our slug populations are extremely high and past experience showed they have major effects on cover crops, especially the vetch we have planted.

A big thank you to all the Operation Advisory Group members who have attended our weekly field walks and helped make decisions for our cover crops.

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

Our butternut hand harvest of replicated plots was completed on the 9^th and 10^th of March. Four subplots of 6m² were sampled from each plot. All butternuts within the sample area were cut from the plant, counted, and weighed. A butternut subsample was collected for Brix, dry matter, nitrogen, and carbon analysis. The plant residue was also weighed, and a subsample was collected for dry matter, nitrogen, and carbon analysis. Notably, although there are slight differences in the various metrics we assessed, none are significant at a 5% confidence level.

Butternut fruit yield

Yields were very high. We planted assuming 25 – 30 T/ha of butternuts but grew almost double that. The conventional treatment had an average yield of 52.74 T/ha, the Hybrid treatment had 52.00 T/ha, and the Regenerative treatment had 49.44 T/ha.

Butternut residue

The Conventional treatment had an average residue biomass of 20.57 T/ha, the Hybrid treatment had 20.25 T/ha, and the Regenerative treatment had 17.56 T/ha with differences again not significant.

Dry Matter

A subsample of butternut residue was dried to calculate the dry matter percentage. All three treatments had an average dry matter of 16%.

The Conventional treatment had an average dry matter of 8.44 T/ha, the Hybrid treatment 8.37 T/ha, and the Regenerative treatment 7.77 T/ha. While showing slight differences, these are again not significant differences between treatments (P>0.05).

Nitrogen percentage

The nitrogen percentage in the butternut plant residue was determined by Hill Laboratories. The Conventional treatment butternut residue had an average nitrogen percentage of 1.95%, the Hybrid treatment had 1.78%, and the Regenerative treatment had 1.70%.

To calculate the amount of nitrogen in the butternut residue, the dry matter (T/ha) was multiplied by the nitrogen percentage and converted to kg/ha. The Conventional treatment had 163.92 kg N/ha, the Hybrid treatment had 148.63 kg N/ha, and the Regenerative treatment had 131.97 kg N/ha.

Carbon percentage

The percentage of carbon in the butternut residue was determined by Hill Laboratories. The Conventional treatment had an average carbon percentage of 35.25%, the Hybrid treatment had 34.20%, and the Regenerative treatment had 35.50%.

The butternut residue dry matter (T/ha) was multiplied by the carbon percentage to get tonnes of carbon per hectare. The Conventional treatment had 2.95 T C/ha, the Hybrid treatment 2.86 T C/ha, and the Regenerative treatment 2.76 T C/ha.

Brix

To measure Brix levels, a subsample was taken from two butternuts from each sample area. The subsample was grated and squished in a garlic crusher, and the juice was tested with a Refractometer.

The Conventional treatment had an average Brix level of 7.1%, the Hybrid treatment 7.9%, and the Regenerative treatment 7.0%.

If Wattie’s had harvested the butternuts, Brix levels would have been assessed prior to harvest. Heniz-Wattie’s minimum brix level before harvest is 7%, ideally, they would be harvested between 9–10% brix. As the butternuts were harvested by a local grower approximately one month earlier than Heinz-Wattie’s standard harvest timing, the Brix levels were on the lower side.

Thanks, Phillip Schofield, Phillipa Page, Dan Bloomer, and Olivia Webster, for helping with the hand harvest.

A big thank you to all the Operation Advisory Group members who attended our weekly field walks throughout the season, providing us with their expertise and helping make decisions.

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 funders; MPI, Process Vegetables NZ, McCain Foods, Heinz-Watties and Hill-Labs.

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

MicroFarm Biodiversity Update – LandWISE – Promoting sustainable land management

Our hand harvest samples were taken from 3 m × 2 m areas within each of the four subplots of each plot; 16 per treatment, 48 in all. All butternuts within the sample area were cut from the plant, counted, and weighed. A subsample was collected for Brix, dry matter, nitrogen, and carbon analysis. The plant residue was also weighed, and a subsample was collected for dry matter, nitrogen, and carbon analysis.

On the 10th of March, the butternuts were cut for fresh market and placed into windrows ready to be collected into bins.

The main differences between treatments were cultivation method, biological and foliar applications, and fertiliser inputs. The Hybrid and Regenerative treatments were strip-tilled, while the Conventional treatment was fully cultivated. The Regenerative treatment received the most biological and foliar applications, the Hybrid treatment received some, and the Conventional treatment received none. The Regenerative treatment also received significantly less nitrogen (18 kg N/ha) compared with the Conventional treatment (77 kg N/ha) and the Hybrid treatment (67 kg N/ha).

The Conventional treatment yielded 52.74 T/ha, the Hybrid treatment yielded 52.00 T/ha, and the regenerative treatment yielded 49.44 T/ha. While these yields look slightly different, there is no significant difference in yield between the treatments (P>0.05). Our highest and lowest yielding sub-plots were both in the regenerative treatment!

We will discuss these findings at the LandWISE Conference: Soil Health for Profit in May.

Conference information and registration is available on our website.

We were delighted to have Carys Luke join us as our Summer Intern in 2025-2026. Carys’ key project was measuring soil infiltration rates using disc permeameters. These devices work under tension, so water has to be pulled into the soil by capillary forces. By controlling the amount of tension, we can set the soil pore sizes that are dragging water in, and so we can get an estimate of the soil’s pore size distribution.

There’s a fair bit of maths and interpretation so to help, we made an online calculator and published interpretation guidance. We would like to hear your feedback if you go looking. The equipment is not commonly available and is mostly a research tool rather than for everyday farmer use. If you think you would benefit from measurements, contact us and we can discuss options.

This report evaluates soil water infiltration across conventional, hybrid, and regenerative
management treatments in a randomised block design (12 plots) within the LandWISE
Carbon Positive experiment. Infiltration rates were measured using disc permeameters
at the soil surface and at 10 cm depth under supply tensions of −15, −6, and −3 cm.
Applying water at these tensions enabled hydraulic conductivity to be assessed across
three pore-size domains (<0.2 mm, <0.5 mm, and <1.0 mm), providing insight into pore
size distribution and how it varies between treatments.

Infiltration generally increased as water tension became less negative; however, contrary to published literature, infiltration often plateaued or declined between −15 cm and −6 cm tensions. The readings at lower tension (-3cm head vs -15cm head) should icrease because more mores are taking water. These results indicate that our measurements at −15 cm tension frequently did not reach true steady state. You can see this in Figure 6.

A key recommendation is to ensure sufficient time is allowed, and that more measurements, possibly at greater intervals, are made than were done for this study. In a soil such as ours, it can take a very long time (hours) to get to the steady state, and it may not be apparent until data gets analysed. Ooops.

Carys’ full report is available in our file stack.

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