Irrigation – LandWISE – Promoting sustainable land management https://www.landwise.org.nz LandWISE promotes sustainable production through leadership, support and research. Since we began in a field in 1999, we’ve completed a range of projects helping to conserve our soils, use our water wisely and get environmental and economic benefits from new (and old) technology options. Tue, 07 Apr 2026 04:01:19 +0000 en-NZ hourly 1 https://wordpress.org/?v=6.9.4 https://i0.wp.com/www.landwise.org.nz/wp-content/uploads/2022/03/Landwise-logo-sm20.jpg.jpg?fit=32%2C11&ssl=1 Irrigation – LandWISE – Promoting sustainable land management https://www.landwise.org.nz 32 32 204183287 Winter Cover Crops https://www.landwise.org.nz/2026/03/27/winter-cover-crops/ Fri, 27 Mar 2026 03:23:21 +0000 https://www.landwise.org.nz/?p=3726 After the 2025-2026 butternut crop was harvested, the Regenerative treatment received Omya Calciprills (150 kg/ha), Sulphur (30 kg/ha), Boron (10 kg/ha), and Humates (5 kg/ha). This mix has been applied annually to stimulate soil microbes for good soil health. Thanks to Websters Hydrated Lime for supplying the micronutrients again.

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.

First pass with the discs.
After the second pass with the discs.

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.

Cover Crops getting direct drilled.

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.

Post-drilling irrigation using our LEPA machine

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.

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Soil Infiltration Calculator https://www.landwise.org.nz/2025/12/18/soil-infiltration-calculator/ Wed, 17 Dec 2025 19:42:04 +0000 https://www.landwise.org.nz/?p=3344

We have launched an online web calculator to process soil infiltration rate measurements collected using a Disc Permeameter. The calculator analyses measurements made at different tensions. It is a beta product, primarily made to assist us in assessing soil infiltration, porosity etc. We are keen for any feedback!

Disc permeameters (also called tension infiltrometers) are valuable tools for measuring how water moves through soil. Unlike ring infiltrometers that measure saturated flow, disc permeameters apply water at controlled negative pressure (tension), allowing you to assess the amount of flow through specific pore sizes. This gives you deeper insights into soil structure, compaction, and drainage capacity.

By measuring at multiple tensions, you can determine how much flow occurs through large structural pores versus the fine-textured soil matrix. This reveals critical information about soil structure and preferential flow pathways. Different pores sizes provide different benefits:

  • Macropores: > 0.075-0.1 mm – drainage, aeration, rapid flow
  • Mesopores: 0.03-0.075 mm – intermediate drainage and retention
  • Micropores: < 0.03 mm – water retention, slow flow (requires tensions < -100 cm)

Disc permeameters measure flow through macropores and larger mesopores only. They cannot assess micropores, which require different methods such as pressure plate apparatus or water retention curves. The practical tension limit for disc permeameters is about -15 to -20 cm due to air entry through membranes and extremely slow infiltration rates at more negative tensions.

We have a comprehensive guide that explains the permeameters and processes in more detail and a Frequently asked question page to help out.

If you want to try understanding your soil this way, contact us. The equipment is not readily available and it does take effort to learn to use if correctly.

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Irrigation System Testing https://www.landwise.org.nz/2025/11/18/irrigation-system-testing/ Mon, 17 Nov 2025 22:55:47 +0000 https://www.landwise.org.nz/?p=3188 With the new irrigation season in sight, we have been working on ways to help growers check their systems are performing as they should. Page Bloomer has made a number of online irrigation system performance calculators available, and you can find these in our Tools section. Do note that these a “beta” versions and still undergoing testing. We encourage you to use them, and let us know if you encounter any problems.

So far we have calculators for:

We sent Dan off to keep working on calculators for:

  • Multiple Spraylines
  • Drip/Micro Irrigation
  • a few other ideas!
  • and we haven’t seen him for a while

These calculators are based on the 2005 Irrigation Code of Practice for System Evaluation. Its methods have been very well tested over the years and we a proud to have been involved from the start.

The calculators do not store any of your data. The calculations are done in the webpage on your computer and are deleted when you refresh or close the page. That means only you have your data, but if you want to redo things, you’ll have to start again.

Please give us feedback. We are thinking of adapting the Fertiliser Application calculator to this format as well if we get good reviews. And if people want to save their work, we can look into that too.


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Green Beans and Carbon Positive https://www.landwise.org.nz/2025/03/30/green-beans-and-carbon-positive/ Sun, 30 Mar 2025 03:32:04 +0000 https://www.landwise.org.nz/?p=2411

The Carbon Positive programme continues. Our McCain Foods green bean crop has been successfully harvested and yield and quality data captured. Post-harvest, Alex and Oliva completed VSA tests in all the plots, and those and other data are being collated and processed.

All treatments achieved good yields, but we found significant differences between them. We harvested 1 m2 of crop from each of four sub-plots in each of our 12 plots. That gave us lots of beans which were then removed by hand, weighed and graded. We also got factory results from the different treatments. The box plot graph below shows the average yield (the Xs) and variability in each treatment as determined from our hand harvest plots.

The biggest cause of down-grading at the factory was pod damage associated with harvesting and transport. Other than that, we had a very clean crop.

Yield measurements from the three Carbon Positive crops showed significant differences between each treatment. All were good.

So why the differences?

The regenerative plots had the biggest plants. This was seen throughout the season with the canopy ground cover always being ahead in the regenerative plots. Towards harvest, we found the conventional plots had two weeks when their growth appeared to be checked. We know it wasn’t soil moisture or nitrogen availability, but we can’t put a finger on a cause.

Both the conventional and hybrid areas were planted in process peas at the end of August. The soil was cold and wet and we noticed compaction from cultivation and machinery passes. The conventional plots were ploughed and disced, and the hybrid plots direct-drilled before the cover crop was mulched. The regenerative plots were kept in cover crop, which was mechanically terminated before a period of fallow.

All the plots were disc-ripped about three weeks before planting, then sprayed with glyphosate to achieve a stale seedbed before bean planting on 28 December. Both the conventional and hybrid plots received nitrogen fertiliser broadcast near full canopy. The regenerative plots did not receive solid fertiliser, but did get a foliar application as part of spraying for disease and caterpillars. The spray programmes were different from the pre-emergence herbicides through the crop protection programme.

We can’t say what made the differences to the yields that were achieved, because our trial is not set up that way. We are comparing the results of overall management policy over six years rather than assessing the effect of any single input.

So, we can’t say why. Maybe there was less disease pressure by missing peas? Maybe the better soil physical state by avoiding early cultivation and planting in the wet made a difference? Maybe the cover crop biomass was feeding the soil microbes or releasing nutrients?  Maybe all of these? Maybe something else…

The VSA assessments appear to show differences developing in the different treatments. We need to keep monitoring and see a longer-term trend, but for now, the regenerative plots are starting to score a little better. The soil appears somewhat darker, suggesting it may be building soil carbon levels (we’ll be lab-testing soon so keep an eye out for that) and it has fewer large soil lumps (in our case mainly showing compaction damage). It does suggest that working the soil and driving over it when cold and wet in August had impact.

Conventional VSA
Hybrid VSA
Regenerative VSA

We expect to drill the winter cover crops in the first week of April. With continuing dryness, we have applied irrigation to make the soil moist enough for drilling. Our intention is to aerate after drilling to avoid compacting the soil again. Then we’ll leave everything alone until spring to allow the soil to breathe, microbes to do their thing, and roots and earthworms to explore as easily as possible.

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2024 McCains Pea Production https://www.landwise.org.nz/2024/11/29/2024-mccains-pea-production/ https://www.landwise.org.nz/2024/11/29/2024-mccains-pea-production/#comments Thu, 28 Nov 2024 19:00:57 +0000 https://www.landwise.org.nz/?p=2183 Peas were planted for McCain Foods on the 3rd of October as part of our Carbon Positive trial. This was a week after the target planting date due to wet soil conditions at the end of September.

Planting

  • Conventional treatment: ploughed, disced x 2, power-harrowed, peas drilled, rolled
  • Hybrid treatment: peas direct drilled, rolled
  • Regenerative treatment: not planted in peas

Winter cover crops in both the Conventional and Hybrid treatments were sprayed out early, and the soil stayed wet. The Conventional treatment was encouraged to dry by cultivating to ‘open up’ the soil. The Hybrid, which was not cultivated, remained very wet, making the soil more vulnerable to compaction at planting. The soil was wet enough to leave defined drill lines, and in some places open slots.

We decided not to plant the Regen treatment in early peas. We wanted to avoid driving on wet soil with heavy machinery, minimising compaction, and retained the soil in a ‘restorative phase’ for longer, ahead of planting beans in late December.

Crop Monitoring

The impact of planting into wet soil in the Hybrid treatment was seen almost immediately. Establishment was slower, and the plant population significantly lower than the Conventional treatment.

We saw similar trends in canopy cover percentage, with the Hybrid treatment lower than the Conventional one. The Regenerative cover crop was mulched on the 1st of October to stop the radish component of the cover crop mix from flowering. The residue was later disced in to mix soil with the residue and speed up breakdown. That was not been sufficient to kill the oats in the multispecies cover crop, and the regrowth required ongoing management.

Both the Conventional and Hybrid treatments had one post-emergence herbicide application (Bruno + Quantum). No pre-emergence herbicide was applied due to lack of forecast rain early in the season.

The dry weather through November brought forward our harvesting date. A fungicide application was recommended, but we were too close to the 14 day pre-harvest interval so none was applied. Disease pressure was low so we had few issues.

The dry spring meant the irrigator has been consistently running. Between planting on the 3rd of September and harvest on the 27th November we received 46.7mm of rainfall. The irrigator made six passes and applied approximately 96mm of irrigation.

Harvest took place on the 26th of November, read more in our harvest article!

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New Dam Safety Regulations https://www.landwise.org.nz/2024/10/10/new-dam-safety-regulations/ Thu, 10 Oct 2024 01:51:00 +0000 https://www.landwise.org.nz/?p=2156 This is a guest post from MBIE.

Irrigation dam. (Image supplied by MBIE)

Dam Safety Regulations are in force

The Building (Dam Safety) Regulations 2022 commenced on 13 May 2024.

The regulations have been made to improve the resilience and maintenance of Aotearoa New Zealand’s dams, protecting people, property and the environment from the potential impacts of dam failures.

Only classifiable dams are impacted by the regulations. Dams are classifiable if they are 4 or more metres in height and store 20,000 or more cubic metres volume of water, or other fluid.

Background to the Regulations
The Regulations were made by the Government in May 2022 and provide a nationally consistent approach to dam safety. Having a dam safety framework brings Aotearoa New Zealand in line with most other countries in the Organisation for Economic Co-operation and Development (OECD).

Since May 2022, the Ministry of Business, Innovation and Employment (MBIE) has been working with industry groups and regional authorities to ensure dam owners are aware of the Regulations and provide them with information and resources to support them to meet their responsibilities when the Regulations came into effect.

What do the Regulations mean for you?
If you are the owner of a water retention structure, firstly you need to determine if your structure meets the definition of a classifiable dam (that is, if it meets the height and volume thresholds).

  • If you determine that your dam is classifiable, you will then need to determine your dam’s potential impact classification (PIC). If you do not have a classifiable dam, no further action is required under these Regulations.
  • Once the PIC has been determined, you will need to then have the PIC audited and certified by a Recognised Engineer, who will work with the dam owner to complete a dam classification certificate.
  • Dam classification certificates need to be submitted to the relevant regional authority.
  • Owners of dams with a medium or high PIC have further actions they need to take.
  • The only additional requirement for owners of dams with a low PIC is to review their dam’s PIC within five years of the regional authority approving it.
  • If you own a dam and fail to meet your responsibilities under the law (the Building Act 2004 Regulations), then you may be liable for a fine.

Resources to help you
You can read more about the definitions, regulations, and find resources to support you, on MBIE’s Building Performance website: www.building.govt.nz/managing-buildings/dam-safety/

Included in these resources is the Measuring and calculating the height and volume of agricultural dams resource. This is designed to help horticultural or agricultural dam owners calculate the volume of their dam and understand if they are impacted by the Regulations.

MBIE has also published another resource, the Potential Impact Classification checklist, which is a checklist to support dam owners to identify and collate information for a PIC assessment.

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Rebuilding Our Soils – Successful Conference https://www.landwise.org.nz/2024/05/22/rebuilding-our-soils-successful-conference/ Tue, 21 May 2024 22:32:10 +0000 https://www.landwise.org.nz/?p=2008

Many thanks to everybody involved in our 2024 Annual Conference! All up we had 99 registrants who heard from 23 amazing presenters and saw 9 different practical demonstrations. Our special thanks to everyone who contributed by sharing their knowledge and experiences, and to delegates for their active interaction. Thanks to Pure Catering and our hosts at the Havelock North Function Centre and at the Centre for Land and Water which hosts our MicroFarm and the demonstrations.

Many thanks also to our conference sponsors and supporters. These organisations support us through the year as well as for the conference and we are very grateful. They are the most loyal of partners we could hope for.

Ka mau te wehi!

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Focus on Agritech https://www.landwise.org.nz/2024/04/26/focus-on-agritech/ Thu, 25 Apr 2024 22:32:45 +0000 https://www.landwise.org.nz/?p=1964 Examples and discussions for horticulture and cropping

Sustainable production through technology has been one of the key themes through the history of LandWISE Inc. We started with minimum tillage and strip tillage equipment, then rapidly adopted RTK GPS and autosteer, which we saw unlocked many opportunities for financial and environmental gains. We’ve looked a precision viticulture, canopy monitoring, crop mapping, soil sensing and more. We investigated agricultural robotics and options for management software. So much stuff to keep up with!

The 2024 LandWISE Conference has three components dedicated to agritech: an innovation panel discussing the experience of taking an idea to commercial reality, a group presenting technologies that automate data collection and help make sense of it all to support management decision making, and a practical in-paddock session where equipment will be demonstrated.

In the session, “Commercialising New Technology”, Andrew Cameron will chair a discussion between Tim Neale from Data Farming, Matt Flowerday from Landkind, Clare Bradley from Agrisea NZ, Hamish Penny from Croptide, and Richard Beaumont from AGOVOR. Different people, different technologies, different growth paths and different insights.

“Data Capture and Understanding” builds on the agritech theme, presenting technologies to capture data remotely and turn it into information to assist management. Tim Neale’s DataFarming platform presents satellite data and interpretations, Matt Flowerday capture aerial imagery and has a platform to plan farm management spatially, Hamish Penny and Croptide have a “smartwatch” for plants, collecting internal water status information and sending it straight to your phone, and Lia Willis helps clients pull different layers of data together.

The Horizons Regional Council Practical Session at the MicroFarm will display technologies and give opportunity to discuss details with the people with answers. Look for drones and robots from Airborne Solutions, AGOVOR and Robomate, cover crops and roller crimpers, pest predators with Bioforce and new irrigation technology from WaterForce!

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January 2024 Tomato Update https://www.landwise.org.nz/2024/01/26/january-2024-tomato-update/ Fri, 26 Jan 2024 02:54:37 +0000 https://www.landwise.org.nz/?p=1718 The Carbon Positive tomato crop has now been growing for 13 weeks. Our estimated harvest date is the 5th March, so just under six weeks remaining until harvest. All treatments have had a good fruit set and are reasonably disease free (minus a small amount of bacterial speck). We are on track for a good result at harvest. There are visual differences between the treatments. The conventional treatment has a dense canopy, the regenerative treatment has a more open canopy and the fruit is more exposed. The hybrid is somewhere in between. Management for the month of January has included three spray applications, two irrigations and one granular fertiliser application. More on this below.

Canopy Development Week 2 – 13

Pest Management

In mid-January we started to see holes appearing in tomatoes, caused by corn ear worm/tomato fruit worm. The first insecticide application we used (Benevia) is registered for chewing insects, so caterpillars were targeted early in the season. However, subsequent insecticides have predominantly targeted sucking insects (psyllid/thrips/aphids/whitefly). We applied Uphold (spinetoram) across all treatments to control fruit worm. The crop was inspected five days after application, and found no active caterpillars. Additionally, we still haven’t seen any psyllid on the sticky traps in the field, which is positive!

Images of tomato fruit worm found in trial plots

Nutrient Management

We have been regularly monitoring soil nitrate levels using the Nitrate Quick Test method. Nitrate levels have been declining since side dressing, which indicates that plant demand is exceeding supply of nitrogen. Fruit set has been good and we want to ensure there is enough energy in the canopy to increase fruit size (and yield).

Graph showing average Nitrate-N in top 30cm of soil profile, in each treatment, and timing of fertiliser applications.

Additionally, we have been doing monthly leaf tests to look at nutrient levels in the tomato leaves. There have been signs of leaf rolling, and purpling along the leaf margins in all treatments in January. This was more distinct in the Regen treatment. This is an indication of low phosphorus or potassium causing plant stress.

Image of purpling on underside of leaf (Plot 3- Regen Treatment)

Leaf tests showed lower than optimum Nitrogen percentages in the leaf for this stage in the season, as well as low P and K percentages (graph below showing N%). The Operations Advisory Group decided to apply a late application of fertiliser across all treatments. The Regenerative treatment has appeared stressed compared to the other treatments in recent weeks. There has been concern as to whether the canopy is big enough to size the fruit already set. The OAG used the information available to make a justified ‘grower decision’ to address the apparent nutrient deficiencies.

Graph showing Nitrogen percentage in tomato leaf, by treatment by plot, December and January analysis. Optimum range at different growth stages displayed as pink band.

Nitrogen concentrations in the leaf were lower in the Regen treatment than the other two treatments, so we decided to apply a higher rate of N, to support the plants to harvest. The OAG decided to apply YaraRega 9-0-27.5. The Conventional and Hybrid treatment had 9kg N and 27.5kg K applied (100kg/ha). The Regen treatment had 18kg N and 55kg K applied (200kg/ha). This is somewhat counter intuitive for the Regen treatment, however all of the treatments have now received the same amount of N, around 90kgN/ha. Even with this application the Regen plots have had much less potassium applied compared to the other two treatments.

Drone Application

Fertiliser applied late in the season is normally done using a tractor mounted spreader. However, because our plots are 12m wide, we are unable to get the desired spread width this way. We worked with Airborne Solutions to apply the fertiliser with their drone, to be more targeted with our application, plus avoids damaging the plants by driving over with a ground spreader. The spread of the product was uniform and spread to the 12m width of our plots. The drone carries 40kg of product so was a quick job to get done on our 1.5ha.

Images of Airborne Solutions drone spreading fertiliser over trial area
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Carbon Positive at the MicroFarm – February 2024 Field Walk https://www.landwise.org.nz/2024/01/26/carbon-positive-at-the-microfarm-february-2024-field-walk/ Fri, 26 Jan 2024 02:11:43 +0000 https://www.landwise.org.nz/?p=1763

Please register at Eventbrite

Once again, we are opening the gates and doors to the public for a Carbon Positive at the MicroFarm field walk to view and discuss the Heinz-Wattie’s process tomato crop.

We’ve been making nutrient, irrigation and crop protection decisions – come along and discuss our strategies and apparent effectiveness!

Image from our January 2024 field walk

Please register at Eventbrite

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