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.

By the time our summer crop butternuts were removed from the Carbon Positive plots, the vines had dried to rope. We disced and direct drilled cover crop seed but couldn’t run an aerator through without massive tangling.

On 26 March, annual ryegrass was sown in both the Conventional and Hybrid plots, and a Triticale/Vetch mix in the Regenerative plots. With very dry, rubbly soil, we irrigated after sowing to help germination.

Because we’ve been disappointed by vetch in recent crops, Olivia ran a germination trial, placing 100 seeds in a tray of plot soil and leaving it outside. This showed 88% germination under field conditions, which we were happy about.

Triticale was first to emerge in drilled plots, with significant numbers by 1 April. Ryegrass and vetch were slower, but well underway by 7 April.

Triticale and Vetch

Annual Ryegrass

By early May, the triticale was well established with roots down at least 20 cm. The vetch roots were also reaching down and had good nodulation.

The ground cover under each cover crop is shown in the chart below. After a lag at initial germination, the ryegrass plots grew at the same rate as the triticale and vetch but did not catch up. The drop at the beginning of June followed an attempt to aerate the soil through a full cover crop once the butternut vine had sufficiently rotted. However, there was some crop damage and the average cover dropped. The regenerative triticale and vetch plots did not return to the previous full ground cover. While the triticale was recovering, around mid-July a leaf rust began spreading through the plots. Even as growth in the Conventional and Hybrid ryegrass plots continued lifting in August, the triticale weakened.

Examples of canopy images taken on 17 August show the ground is well covered, although there are more gaps in the Regenerative image and the presence of rust is apparent.

Conventional Annual Ryegrass

Hybrid Annual Ryegrass

Regenerative Triticale & Vetch

In mid-August we planned to start ground preparation by broadcast spraying the Conventional plots with glyphosate and Torus, and strip-spray the Hybrid and Regenerative plots with glufosinate and Torus. We took above-ground biomass samples on 8 August taking two 0.25 m² subsamples in each of four sub-plots per plot. The charts below show there is no difference in dry matter percentage between treatments. Despite the lower ground cover in the Regenerative plots as assessed by Canopeo, there is a significant difference in above-ground dry biomass compared to the other two which are the same.

Weather has impacted our plans to spray out the cover crops. Our next summer crop will be food quality maize, and the planting date is flexible so we can delay somewhat. But we do want to get next year’s cover crops in while the autumn is still warm, so we don’t want to wait too long.

We plan a public field walk at the MicroFarm on Carbon Positive Field Walk at 1:00 pm on Wednesday 16 September.

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.

Making sense of carbon movements. History of strip-till.

Co-founder and manager of LandWISE since 1999, Dan’s career is diverse, with a constant theme of sustainable use of land and water resources. His post-graduate studies included an MScTech in innovation Management and adoption in the primary sector, and a PhD investigating the potential of ultra-low energy electric weeding.  He brings experience across fresh and process vegetable growing, kiwifruit and arable production, to complement expertise in extension, soil health and efficient water management.

Dan is the architect of the Carbon Positive project. At LandWISE 2026, he will present data from soil carbon monitoring in the Carbon Positive project and introduce the use of AI to help understand changes in soil carbon pools.  Powerful, yes. But trustworthy?

Later, he will dive back in history to recall pioneering research into the adoption of strip tillage to minimise soil erosion and soil health impacts. That work saw the formation of LandWISE, ultimately as a stand-alone organisation promoting sustainable production through leadership, support and research. Dan remains a strong advocate for strip-till done right, having seen first-hand its contribution to better soil health, minimised fuel requirements, and financial advantages.

Past Chair of LandWISE, John Evans will discuss his farming career at “Soil Health for Profit” in May. Over more than four decades active farming, he’s seen a number of farming systems arrive and be replaced.

John was exposed to soil improvement at a young age as his parent’s developed half of the property from Gorse Broom Blackberry and Willows into a highly productive irrigated mixed system. After returning from Lincoln College and helping with the irrigation development the farm was sold, and another larger rundown property was purchased in Dorie.

Over the next 36 years John continued his soils interest and converted the property to intensive cropping with irrigation. Pivoting the operation and taking up the opportunities that came along, he finished with a highly productive arable livestock farm with a high quality, productive specialist seed operation.

He was and is always active in his own research and hosting and supporting Foundation for Arable Research (FAR) projects. Looking back, has asks, “Have I always been a regenerative farmer?”

Practical: Sprayer tune-up and calibration

Andy Mawley has spent his entire life working with spray application, from orchards to broadacre farming and large-scale cropping operations. He understands how important it is to maximise the effectiveness of the chemistry you’re using—and how often small, easily overlooked details can impact performance.

Andy brings practical experience and straightforward solutions to help improve outcomes across a wide range of operations. He travels extensively, working alongside growers and operators to identify opportunities for improvement, while also continuing to learn from each unique situation.

With this depth of experience and a fresh, outside perspective, Andy offers valuable insights to help refine spray coverage, improve application practices, and enhance overall efficiency. He’ll run a practical refresher during the Horizons Regional Council sponsored Field Event.

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.