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.

Our 2026-2027 summer crop will be a crop of maize grown for Nicolle Grain. The ultimate destination is your plate of nachos, once the grain has been turned into corn chips. We’re grateful that Patrick and Tom Nicolle have agreed to work with us this summer, providing an alternative to the sweetcorn crop that had been planned prior to McCain Foods’ factory closure.

The plan for the coming season is an adaptation of the sweetcorn plan that was our first crop in the Carbon Positive trial. One change is that none of the treatments have been grazed over winter. We have sent soil samples to Hill Labs for Basic, Sulphur profile and potentially available nitrogen PMN testing. We will use those results and our regular soil nitrate monitoring to determine the crop nutrition programme for each treatment.

^{* fertiliser rates to be reviewed when lab test results received.
# use later in crop if needed for escapes. Maybe the interrow cover crop mulch in the strip-till plots will be enough.}

With rain in mid-August, we already missed our planned spray-out date! We wanted a 6-week interval before cultivation. Given the crop is maize and the harvest date is less important than for process crops, we are not overly concerned, but we do want to get the crop out early enough for good winter cover crop establishment in 2027.

Our latest soil nitrate testing showed that levels continue to be very low and often non-detectable (<5ppm) using the Nitrate Quick Test. They do suggest that the regenerative plots might be a little higher than the others, perhaps a reflection of the vetch component in the cover crop. It will be interesting to see if there are any differences in the PMN in the Conventional and Hybrid ryegrass, and Regenerative triticale and vetch plots.

We will have regular field walks so everyone has opportunity to view the trials firsthand. Make sure you’re signed up to receive notifications.

We recall that 2022-2023 was a la Nina year and 2026 -2027 is looking to be the opposite, an el Nino year. You may recall that our 2022 sweetcorn was impacted by Cyclone Gabrielle. In the end, the yields in the treatments were good, but we don’t know how the flooding impacted any of our results.

Our 2026 LandWISE Conference Opening Speaker, James Hunter, is a farmer with a surprising number of decades under his belt.

Rangitoto Station, farmed by Hunters since 1854, is named a local the Pa site that dates to some of the earliest times of NZ occupation. These attachments, mixed with time working for the Rural Bank in the 1980’s when government schemes (namely the Land Development Encouragement Loan) focused on clearing bush and wetlands – now described as biodiversity, and travel through South and Central America seeing first hand some of Natures wonders struggle with so-called progress reinforced for James that the little things that we have around us must be part of our future. He set out to lift farm performance while protecting all remnant native bush/scrub areas, creating wetlands and improving the quality of water leaving Rangitoto.

Time on QEII and NZ Farm Environment Trust boards strengthened the ethos that farming and looking after things natural are rewarding companions. James is currently questioning whether the “regenerative farming” description fully accounts for so much on Rangitoto Station “that is a buzz”. 

Photo from RNZ – see the full article

“http://www.rnz.co.nz/news/business/570243/disaster-waiting-to-happen-fears-carbon-farming-increases-risk-of-wild-fire.

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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.

In the last five years, he has conducted regenerative trials on kiwifruit orchards to scientifically demonstrate that adopting regenerative practices can improve soil health and increase biodiversity, while remaining profitable.

Pranoy will present some key findings of the regenerative trials over the years and identify the main barriers to the adoption of these practices by the kiwifruit growers.

The session offers practical, real-world insights for growers wanting to apply sustainable and regenerative practices on orchards and farms.

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?”