What to plant?

First off, what should we plant? I don’t think we have yet got our cover crop mixes quite right. This year, our hybrid and regen treatments were planted in a diverse mix of 7 species (black oats, tillage radish, vetch, buckwheat, sunflowers, crimson clover and Persian clover). This was to get lots of plant diversity over the winter.

A frost in May killed the buckwheat and sunflowers, which meant they weren’t present over the winter. We planted tillage radish as it is supposed to be the “crowbar of the soil” and will break through tillage pans. Unfortunately, our radishes knew better, hit the pan and, in some areas, popped themselves 10cm out of the ground. This is potentially an issue for both the hybrid and the regen treatments, as chunks of radish could be picked up by the harvester and end up at the factory which may be a problem for product contamination.

Additionally, the radish started to flower and was beginning to set seed, so radish if unmanaged, could have become be a new weed species for us.

In this conversation, there is the question of how much plant diversity do we need? Some of the species we are using, might be okay in a pastoral grazing scenario, but could be hard to manage in a cropping system and therefore become a weed for us. In the systems we are looking at, are we able to select fewer plants, that provide functional diversity, without adding added complexity of to the management of the cover crop?

Another consideration is disease carry over. We intentionally avoided planting tic beans this year, as they could carry unwanted diseases into the following legume crops. Tic beans may be an option ahead of other crops.

Do we graze?

One of the five regenerative principles is to integrate livestock, which we have not yet done in our Regen treatment. However we have grazed our Conventional treatment, which might seem a bit backwards. It is common for Heretaunga Plains growers to plant an annual ryegrass over the winter and graze it with lambs, so we are including sheep in our Conventional treatment.

In the last two years, we wanted to use the cover crop as a mulch on the surface for our main crop to keep the soil surface covered, another of our regenerative principles. If we have a mulch on the soil surface, we hope it will significantly reduce the need for herbicides. To do this effectively, we need to grow a lot of biomass, and therefore don’t want to have sheep or cattle grazing it. We don’t really have a long enough winter growing season to do both. This is where we find tension between some of the regen principles when applied to an annual cropping system. We might yet include livestock; however, we aren’t sure what this will look like in practice.

In addition, lambs can do considerable soil damage over the winter. The photos below show the difference between grazing for a couple of weeks in dry conditions and grazing over a wet weekend this winter.

When to terminate?

Ahead of the tomato planting last year, we had a cover crop of oats, vetch and lupins in the Regen treatment. You may remember that we planned to use a modified tomato planter, which transplants seedlings directly into a mulched cover crop, eliminating the need for both cultivation and herbicides. Just before planting, we met two problems with this plan.

The first issue was that the cover crop was still actively growing and sucking moisture out of the soil, so the soil was very dry in the regen treatment. This led to large, blocky clumps of soil forming in the top 10cm of the profile. The second issue was that the timing of maturity wasn’t right for mulching and killing the oats. In a test area of cover crop, we found the oats regrow, and we had very limited herbicide options to deal with this. It might have worked if we had waited a couple of weeks, however we were working with a factory schedule and had a planting date that wasn’t very flexible.

We want to apply lessons from that experience this year. We are already seeing low soil moisture levels and low nitrate levels in the Regen treatment. To manage the amount of biomass we have grown, and stop the flowering radish from seeding, the cover crop was mulched on the 1st of October. We expect the mulching will not kill the oats, and that we will need to manage regrowth.

How to terminate?

We planted a winter cover crop, it has grown all winter, so what next? Our Operations Advisory Group is having an ongoing discussion on how we terminate it in our Regen treatment. The initial plan was to use a roller crimper, but the consensus is that this is probably not quite the right tool for the job. We have since mulched the cover crop, but we will need another action to terminate it (oats weren’t mature enough). We have two options; we either spray out the oat regrowth or we cultivate to bury the residue.

This is an important conversation for us, as the use of glyphosate is not widely accepted by the Regenerative community. But our discussions with no-till or minimum tillage growers, and some of the Canterbury regenerative croppers, show it is an important tool for successfully reducing or eliminating cultivation. Most of the literature indicates that cultivating is the number one thing to avoid if we want to increase soil carbon, which is the main metric in this trial.

Weed management is a key consideration in beans as there are few herbicide options. If the crop is too weedy it won’t be harvested. If we cultivate, we will have to manage weeds through a suite of other herbicides that have the potential to as harmful as, or worse than glyphosate when compared using the Environmental Impact Quotient.

How do we best minimise soil disturbance? Both cultivation and herbicide use fall into the category of soil disturbance. The question for our operations group comes down to what is the ‘lesser of two evils’- glyphosate or cultivation?

More questions than answers!

A key lesson from the last two years, is that cover crops are important. We have also found that cover crop management is quite complex. There are a lot of questions we need to ask ourselves:

The post Lessons from two years of winter cover crops appeared first on LandWISE - Promoting sustainable land management.

This is a summary of Dan’s work published under the AgResearch led “Herbicide Resistance Management” project, of which LandWISE was a small co-funder. The full paper was published open access in the Sustainability journal, and is freely available to everybody here>

Abstract:

Seeking low environmental impact alternatives to chemical herbicides that can be integrated into a regenerative agriculture system, we developed and tested flat-plate electrode weeding equipment for applying ultra-low-energy electric shocks to seedlings in the field.

Better than 90% control was achieved for all species, with energy to treat 5 weeds m⁻² equivalent to 15 kJ ha⁻¹ for twincress (Lepidium didymum) and redroot (Amaranthus. powellii), and 363 kJ ha⁻¹ (leaf contact only) and 555kJ ha⁻¹ (plants pressed to soil) for in-ground Italian ryegrass (Lolium multiflorum), all well below our 1 MJ ha⁻¹ target and a fraction of the energy required by any other weeding system.

We compared applications to the leaves only or to leaves pressed against the soil surface, to seedlings growing outside in the ground and to plants growing in bags filled with the same soil. No previous studies have made such direct comparisons. Our research indicated that greenhouse and in-field results are comparable, other factors remaining constant. The in-ground, outdoor treatments were as effective and efficient as our previously published in-bag, greenhouse trials. The flat-plate system that we tested supports sustainable farming by providing ultra-low-energy weed control suitable for manual, robotic, or conventional deployment without recourse to tillage or chemical herbicides.

Download the full paper here>

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9:00 am to 5:00 pm, Friday 26 July 2024

PIA Event Centre, Pukekohe, New Zealand.

In person only, there is no online version.

The purpose of this workshop is to give a complete overview of non-chemical weed management as part of Integrated Weed Management (IWM) and will include addressing herbicide resistance.

Merf is head of the BHU Future Farming Centre and Merfield Agronomy Ltd and co-owner and director of PhysicalWeeding. He is also the OrganicNZ 2024 Organic Leader of the year for excellence in science communication.

The primary audience is cropping (horticulture and arable) farmers & growers as it is these production systems that have the largest challenge with weeds. Perennial crop (e.g. vines, apples) producers will also benefit with one section dedicated to perennial crops (see below). For anyone dealing with herbicide resistant weeds, this workshop is the start of your solution. There are also some benefits for livestock / pasture systems in terms of the overall concepts of non-chemical and integrated weed management.

Consultants and advisors working with farmer and grower clients, particularly in cropping, will gain considerable benefit, especially regarding the latest technologies. Scientists, especially those dealing with herbicide resistance and working on the transition to non-chemical weed management, will gain valuable insights. The content assumes a reasonable level of understanding and practical experience of commercial agriculture and horticulture systems including weed management. This is a really full on and intense workshop – bring your thinking head! Plenty of caffeine is provided!

Cost is NZ$391.30 excl. GST = $450.00 incl. GST.

This includes a colour handout printout of the presentations. It also includes full catering includes tea, real coffee and snack on arrival, morning and afternoon teas and finger food lunch.
Registration is essential as places are limited.

To register please email charles@merfield.com including:

• Your / your business name and address for the invoice.
• The number of people from your business who will be attending and their names and emails.
• A bit of your background, e.g., farmer, grower, consultant, farm system, e.g., veg, apples, so I have an idea of who is coming.
• Any dietary requirements.

More information at Charles Merfield – One day seminar-workshop on non-chemical weed management

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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!

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).

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.

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.

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.

The post January 2024 Tomato Update appeared first on LandWISE - Promoting sustainable land management.

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!

Please register at Eventbrite

The post Carbon Positive at the MicroFarm – February 2024 Field Walk appeared first on LandWISE - Promoting sustainable land management.

Compare these images with last month’s post here>

Operations

Summary

The below table provides an overview of the three treatments and the main management decisions to date.  

Weed control

Due to continued wet weather we missed the window for our second Sencor (herbicide) application. Watties mechanically weeded with their Rototiller on the 1^st of December, which supressed weed growth in the interrow ahead of side dressing. Andy Lysaght then weeded between the double row of tomatoes with one of his mechanical weeders. This was completed across all treatments.

The Badalini (multi-row rototiller) came through at side dressing, completing a shallow cultivation in the interrow and incorporated a pre-emerge herbicide to supress weeds. The operations team decided we would exclude the pre-emerge herbicide from the regen treatment, with the view that we can mechanically weed again if weeds do get out of control.

Disease management

The weather has generally been cooler and overcast through the early part of the season, perfect conditions for late blight and bacterial speck in tomatoes. Our the spray programmes for the Conventional and Hybrid treatments have been the same and have included regular applications of Kocide Opti (copper) to protect against disease. These treatments have also had two Ridomil Gold MZ applications (protectant fungicide for blight). We are trying to exclude copper applications from the Regen treatment, replacing the coppers with Aureo Gold, a bio-bactericide to control disease (mostly used in kiwifruit). Only one Ridomil application has been applied to the Regen treatment as the canopy was smaller early on and had better air movement around the plants.

Insect pest management

All treatments have had one application of Benevia insecticide. A second application is planned for the Conventional and Hybrid treatments later this week. This is mainly to protect plants against Tomato Potato Psyllid (TPP), however also controls aphids and thrips. Some Biological Control Agents (BCAs) have been released in the trial area to help control insect pests (more detail on this in subsequent post).

Nutrient management

Fertiliser decisions are made by the operations group, along with Mark Redshaw from Yara. A high rate of YaraMila Complex (full N, P, K, S, Mg, B, Fe, Mn, Zn) was applied to the Conventional treatment, with a slightly lower rate of Complex applied to the Hybrid treatment. As the background fertility of the plots is in theory high enough to support a crop of tomatoes, it was decided that the Regen treatment would have an application of nitrogen only, so had YaraLiva Nitrabor applied (N, Ca, B). We have been monitoring Nitrate-N levels using the Nitrate Quick Test every two weeks. Results for the top 15cm is displayed below.

Side-dressing

Fertiliser was applied in bands at side dressing through the Badalini (single pass with herbicide application), and worked into the interrow, close to the rows of tomatoes. The Hybrid treatment interrow surface was particularly hard and had two passes with the rototiller to break up the surface.

Foliar nutrition

All treatments had foliar nutrition with YaraVita Bud Builder applied in early November. Regular foliar applications to both the Hybrid and the Regen treatments are planned and bio-stimulants in the mix have been advised. Caution is being when these products are included with other sprays to minimise the risk of burn. In some cases, crop protection and foliar nutrition products are being applied separately.

Irrigation

Management

Irrigation has started with a 15mm application on 16 December that, after the heat and evapotranspiration over the weekend, barely changed soil moisture in the top 200mm where most of our root activity is currently. A second 15mm application was made immediately after the first, and a third is due.

Bucket test

We did an IRRIG8 bucket test and found a DU = 0.88 which is good.

We will make minor changes to the sprinklers on each end and expect an improvement as a result. At the inlet end, a 180 sprinkler is over-applying (orange line) and at the far end a sprinkler is underapplying.

Now is a great time to check irrigation using the bucket test – it is easy to do, it doesn’t take long, and it costs very little. Have a look at the guidance in our Irrigation Management online learning resource. You will need to login – it is free although we welcome paying members to help run the organisation!

“Carbon Positive” is a project running in partnership with the Hawke’s Bay Future Farming Trust. It is funded by the Ministry for Primary Industries, Hawke’s Bay Regional Council, Kraft Heinz Watties, McCain Foods, and BASF Crop Protection with in-kind support from many others.

The post December in the MicroFarm Tomatoes appeared first on LandWISE - Promoting sustainable land management.

At planting, the regenerative treatment soil was much drier than the other two treatments. While both conventional and hybrid plots were sprayed out early, the regenerative oats/lupin/vetch cover crop was actively growing until just before planting and will have been sucking moisture out of the soil. The seedlings in this treatment have been stressed, which we have tried to address this through a foliar application two weeks after planting. Following recent rain, the plants are now actively growing, however are 10-14 days behind the other two treatments. The agronomy team prefers to avoid irrigation in the first weeks to encourage root growth. Perhaps in this case, water would have enabled root growth?

At the moment, all treatments are reasonably weed free within the beds, albeit a bit weedy in the interrow which will be picked up with a mechanical pass early December (Rototiller). After a week of wet weather last week, and some sunny days this week, weeds are just starting to strike within the beds. We are looking at doing a mechanical pass between the rows of tomatoes to pick these newly germinated weeds up before they get too big – targeting weeds including black nightshade, hairy nightshade, thorn apple, redroot, and wire weed.

We are starting to see some insects in the plots; a few aphids, and thrips. We have started trapping for Tomato Potato Psyllid. We are seeking information on threshold levels for our main pest insects.

Come and visit on Wednesday at 1pm – see for yourself, add to the debate.

The post November in the MicroFarm Tomatoes appeared first on LandWISE - Promoting sustainable land management.

In the vineyard every twelve rows a planted strip of a colourful mix including mustard, buckwheat and phacelia is grown to encourage beneficial insects like lacewings. This crop had become too tall, and was interfering with other orchard operations, so was being roller crimped (rather than mown), with the aim of keeping some of the beneficial insects and get some regrowth in the weeks ahead.

Terminating cover crops using a roller crimper has been suggested for the regenerative treatment in the Carbon Positive trial, to minimise the use of herbicides. In a cropping scenario we would be aiming to have no regrowth of the cover crop, which can be achieved by applying more weight to the implement.

How much would we need on a 2-metre wide machine? We tried terminating our oat/lupin/vetch cover crop by mulching, which result in a number of oat plants being pushed over and laid flat by the mulcher body. It wasn’t a total success, but maybe a crimping roller will do a better job.

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This is the first post with details of Dan’s research into ultralow energy weeding using pulsed micro-shocks. It is an introduction by way of a comprehensive literature review, that was published in the New Zealand Journal of Agricultural Research as part of the AgResearch lead Herbicide Resistance management project. It is published Open Access, so anyone can download the full paper and it is free!

Abstract

For decades, herbicides have provided easy-to-use, cost-effective weed management, but alternatives are desired. Consumer preference for chemical-free food, awareness of environmental impacts, regulation increasingly restricting agrichemical use, and increasing prevalence of herbicide resistance are forcing changes to weed management strategies. New Zealand farming must remain sustainable and profitable while responding to changes in its overseas markets, among which are increasing demands for regeneratively grown, safe, high-quality produce. Current reliance on herbicides should be reduced, with more emphasis on preventative management by cultural means, and weed suppression by alternative technologies. The emergence of agritechnologies incorporating automation, machine vision and artificial intelligence, and development of new techniques for weed destruction, offer alternatives that minimise or avoid the requirement for herbicides, avoid soil disturbance and can work effectively in high crop or crop-residue conditions. We have identified electric weeding as a feasible alternative and pulsed electric microshocks as a very low-energy option requiring a fraction of the energy of any other system. Pulsed microshocks enable an integrated weed management system for vegetable and arable crop production combining cultural controls and inexpensive pre-planting treatments with automated application of chemical-free in-crop weed control. Open-source software enables community development of autonomous deployment for niche crops.

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This is the second post with details of Dan’s electric weeding research. It is a bit “sciencey” because it is a formal research paper, but there is interesting information in it! The research was published in the Journal of Agronomy and is published Open Access, so anyone can download the full paper for free!

The abstract is copied below. If that is of interest, download the paper, and maybe start at the end with section 4 Discussion on page 13, which tells you what was learned. Then if you like, read the introduction, and if you are still interested, read the middle section last – it describes all the details of the experiments that lead to the conclusions. The paper uses megajoules (MJ) as the measure of energy needed per hectare. As a guide, a litre of diesel contains about 38 MJ of energy, or alternatively, 1 MJ is the amount of energy in about 26mL of diesel.

Abstract

A search for energy efficient, non-herbicide weed control methods led to development of a novel electrical weeding technology. This study focuses on weed control efficiency and energy as elements of a system that would include machine vision and robotics to control escape weeds in field crops. Two pulse generation systems, one single and one multiple, were developed and evaluated at different delivered voltages and energies. Greenhouse trials using specially designed and built application and recording technology showed the application of precisely applied micro-shocks with precisely controlled direct current voltage, pulse number, pulse length and period (hereafter PMS) can kill small ryegrass (Lolium multiflorum Lam.), fathen (Chenopodium album L.), redroot (Amaranthus powellii S. Wats.) and black nightshade (Solanum nigrum L.) plants with minimal energy. Plants took as much as two weeks to die. Increasing applied energy increased effectiveness as determined by plant biomass reduction and death rate.

Grasses appear difficult to control once tillering has commenced, and high voltages may destroy leaf blades but not growing points. Broadleaved plants took several days to show evidence of chlorosis which preceded senescence and death. Our results showed that 5 J is sufficient energy to bring about death or severe growth limitation in many seedlings up to 15 cm height. This is as little as 1% of the energy of, and more effective than, ultra-low energy treatments reported in other recent research.

To control five herbicide resistant weeds m^-2, the required energy would be about 0.25 MJ ha^-1 plus transport and actuation energy for weed destruction, as compared to an optimum target of about 20–40 MJ ha^-1 including transport suggested in the literature. PMS can effectively control broadleaved weed seedlings and small non-tillering grasses at a fraction of the energy required by commercially available systems. This indicates PMS has potential as a viable technology for hand-held electric weeders or as part of a site-specific robotic weeding system.

What do you think?

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