There is a lot of discussion these days around environmental factors and the push toward “net zero” emissions. Summit is working together with farmers, grower groups, and industry to provide solutions for customers. Summit have recently been trialling the application of a urease inhibitor to granular Urea and are introducing the N-Shield range to their product offering with further trials planned around the state for 2024.
The N-Shield range is designed to optimise nitrogen efficiency and is the first of Summit’s Enhanced Efficiency Fertilizer products (EEF). The primary aim is to increase the effectiveness of nitrogen utilisation, along with significantly reducing Ammonia volatilization. In higher rainfall zones a dual action NBPT/DCD coating can also minimise the leaching of Nitrates, and in waterlogged situations, Nitrous Oxide emissions caused by the denitrification process.
To find out more on the benefits and how it could work for you, contact your local Area Manager, Alana Alexander on 0417 492 047, or visit the Summit website at www.summitfertz.com.au/news.
This year is shaping up to be a very challenging year for many growers in the region as the impact of last year is really felt from low livestock prices and the dry season reducing income in many farm businesses. It will be more important than ever for growers to make good confident decisions to ensure a profitable outcome for this year, particularly in choosing which new practices or technologies to employ to improve the returns from the limited resources available. In this situation, looking for new farming practices or technologies can boost farm profitability or increase operational efficiency and have a positive impact on the farm business, as long as you avoid the dreaded “I wish I didn’t do that this year” from adopting something new that failed to deliver.
The role of WMG in the process of selecting which new practice or technology will drive farm profitability is to ensure that farmers have the information available to make an informed decision. Sometimes not adopting is the best outcome as it may not be the best fit for your business. This is often a trap for many industry solutions to farming problems, where it is assumed that every practice is completely adoptable by all farming businesses. While there is a plethora of information available to farmers nowadays, it can be very overwhelming trying to work out what will make money and what is just snake oil.
After nearly 2 years in the making, WMG has now pulled the covers off its newest tool on the shelf to guide farmers in successful adoption of new farming practices. Our aim is to help farmers make an informed decision of whether or not to adopt a new practice by ensuring that they have the information available in the first instance. What we have found is that there is a process that all farmers go through, albeit at different speeds, in looking at new farming practices and technologies.
The adoption pathway lays out the steps to adoption that are commonly tackled by farmers as they look to further improve profitability of their farming business. From initially becoming aware of a new practice and learning, the first steps of the adoption pathway are about assembling the information needed to understand the basic concepts. At some point, the decision to trial the new practice is taken, and this can come in many different forms: choosing to conduct a small trial or attend a field day to mull things over in your mind. If successful, adoption then follows into the farming business.
At each point along the way, there are many and varied reasons why farmers get stuck in learning about new farming practices. The adoption pathway identifies this so that we can provide the extra information or support to ensure each new practice or technology can be evaluated with the right amount of information.
The end result that interests WMG is the number of advocates developed for each new farming practice; those farmers who can support other farmers in trialing the new farming practice. Our biggest asset is our farming members and while each of the WMG Team are likely to come and go over time, retaining the knowledge in the farming community is a key step to build the capacity of the region and the resilience of farming.
As farmers in our region engage in the discussion style events, they will come across the adoption survey as it is now part of all WMG activities we conduct with our farmers to measure progress in evaluating new practices. It only takes a couple of minutes to participate but will be an important tool that reduces the uncertainty in deciding whether or not to adopt a new farming practice or technology.
By Nathan Craig, Chief Executive Officer & Melanie Dixon, Mixed Farming Systems Officer
Key Messages
The trial outcomes distinctly highlight the variable responses of lupins, chickpeas, and vetch to uniform herbicide treatments. This variability underscores a critical gap in current agronomic practices – the need for herbicide regimes tailored to each legume species. A one-size-fits-all approach to herbicide application is suboptimal. By developing species-specific herbicide strategies, growers can more effectively manage their crops, leading to improved health and yield.
Background
Grain legumes have been widely grown in Western Australia, with lupins the most dominant species due to their suitability to acidic sandy soils. Although high value pulses may not be suited to all soil types and regions, there are areas of WA (soil type x environment) where they are highly suited. Despite this, the adoption of grain legumes in these areas has been poor and the proportion of pulses in the farming system is suboptimal and in fact declining. There has also been a stagnation of lupin yields. Since the inception of GRDCs Western Regional Cropping Solutions networks (now GRDC Grower Networks), growers have continually highlighted that there are no specifically adapted or consistently profitable break crops/legume options for their farming systems. Research is ongoing to select for acid and chilling tolerant crop species which will expand the areas where grain legumes can reliably be grown in WA. However even with existing species and cultivars, there are rotational and economic advantages from incorporating grain legumes into the farming system that are not being realised.
Aim
This trial investigated the weed control effectiveness of a range of herbicide packages for lupin, chickpea, and vetch to demonstrate that effective weed control options are available for chickpea and vetch.
Methods
A replicated trial site was established on a deep sandy soil type in the West Midlands region of Western Australia. The replicated plot trial comprised three crop species, with lupins serving as the standard grower legumes, and chickpea and vetch selected as alternative legumes for the region (Table 1). The purpose of the trial was to assess the efficacy of a range of best practice herbicide packages across each species (Table 2), and to assess the impact of incorrect application to each crop species and the impact of post-emergent herbicide application. Throughout the season, various measurements were taken to evaluate legume growth, herbicide damage, nodulation, and weed control efficacy.
Trial Design & Treatments
Table 1: General site details
Table 2A: Species
Table 2B: Herbicide Package Treatments. All rates are expressed per hectare.
Results
The trial commenced on soil without prior amelioration, with wheat stubble from the previous year and evidence of cattle grazing. The pre-sowing weed competition was not quantified; however, post-sowing observations indicated a moderate weed burden.
The trial was sown on the 24th of May 2023.
Rainfall & Temperature
Table 1: Monthly Rainfall (mm) and Mean Temperature at closest weather station (Badgingarra) throughout 2023.
Plant Establishment & Weed Populations
Figure 1: Average Plant Density per m² for Lupin, Chickpea, and Vetch Across Various Herbicide Treatments. Error bars denote the standard error of the treatment mean.
Plant establishment (plants/m2) varied between each crop species due to the different target plant density for each crop but was also affected by the herbicide package (Treatment) used (Figure 1). For each species, the herbicide package that was most suited to the species resulted in the highest plant establishment for each crop type. Plant establishment for vetch was very low where the alternative lupin package was used (Treatment 2) while lupin establishment failed where the Vetch herbicide package was used (Treatment 4).
Weed density (total population, plants/m2) was less than 5 plants per square metre across nearly all herbicide packages (Treatments) used (Figure 2). As a rule, weed density tended to be higher for lupin than chickpea or vetch, with weed densities in lupin being highest where chickpea or vetch herbicide package were used (Treatment 3,4), or where no post-emergent lupin herbicides were used (Treatment 5).
Figure 2: Total weed density (population of weeds per m²) for lupin, chickpea, and vetch across the eight herbicide packages (Treatments) tested. Note: Both broadleaf and grass weeds are included in total weed density. Assessment completed on the 4th October 2023 near the maturity stage for lupin to assess the total number of weeds surviving the crop/year. Error bars denote the standard error of the treatment mean.
Herbicide Damage Assessment
Figure 3: Visual assessment of herbicide damage for lupin, chickpea, and vetch across the range of herbicide packages tested at the Dandaragan site in 2023. The site was assessed on the 24th of August 2023 near first flowering stage of lupin.
Visual assessment of herbicide damage for all crop species varied considerably when measured on the 24th of August following post-emergent application on the 21st of June (Figure 3). Herbicide damage was greatest in the treatments that had post emergent herbicide applications (Treatments 1-4) and within these, herbicide damage was greatest where the herbicide package was applied to the alternate crops (i.e. when lupin herbicide package was applied to chickpea or vetch for example). Nodulation was also assessed for all crop species on the 24th of August, with lupin nodulation severely reduced where herbicide package 3 and 4 (chickpea and vetch package) were used, and chickpea and vetch nodulation tended to be lower where post emergent herbicides were applied (Figure 4, Treatment 1-4).
Nodulation Score
Figure 4: Nodulation score for Lupin, Chickpea, and Vetch Across Various Herbicide Treatments. Assessment was taken on the 24th August 2023. Error bars denote the standard error of the treatment mean.
Crop Biomass
Figure 5: Biomass at the commencement of flowering (kg DM/ha) for Lupin, Chickpea, and Vetch Across Various Herbicide Treatments. Sampling occurred on the 24th August 2023 near the first flowering stage of lupin. Error bars denote the standard error of the treatment mean.
August Biomass highlights significant variation across herbicide treatments among the three legume species (Figure 5). Chickpea and Vetch performed poorly under Treatments 1 and Treatment 2. In most treatments Lupins outperformed Chickpea and Vetch in August dry matter production, with the exceptions of Treatment 3, Treatment 4 and Treatment 7 which were chickpea, vetch, and chickpea herbicide packages (respectively). Biomass at this crop stage was generally the inverse of herbicide damage and biomass measurements were taken to quantify the impact of herbicide damage.
The trend in reduction of biomass across herbicide packages (Treatments) continued into plant maturity biomass (dry matter) which were taken on the 4th of October (Figure 6). Lupin tended to have the highest biomass production across all crop types and treatments, with the exception of Treatments 3 and 4. The use of herbicide packages not suited to crop species had the greatest impact on biomass production, with post emergent application of chemicals having the greatest impact on biomass production.
Figure 6: Biomass at peak biomass (kg DM/ha) for Lupin, Chickpea, and Vetch Across Various Herbicide Treatments. Sampling occurred on the 4th of October 2023 prior to the leaf-drop stage of lupin. Error bars denote the standard error of the treatment mean.
Grain Yield
Figure 7: Harvest Yield (t/ha) for lupin, chickpea, and vetch across various herbicide packages (Treatments). Error bars denote the standard error of the treatment mean.
Grain Quality and Yield Measurements were completed by mechanical harvest on the 17th November (Figure 7). There were some plots that were difficult to harvest as there was insufficient grain produced where biomass production was extremely low (for example, lupin in Treatment 3 and 4). Lupin grain yield was greater than 2.5 t/ha across all treatments, with the exception of Treatment 3 and 4, and chickpea grain yield varied between 1.8 to 2.2 t/ha where there was little herbicide damage, and 0.8 to 1.4 t/ha where biomass was reduced.
Conclusions
There are three main highlights in this trial that are of benefit to growers when considering growing a grain legume. The first is that effective weed control was achieved in chickpea and vetch relative to lupin, where in some instances, weed control was more effective than in lupin. Part of this was related to lower crop competition by lupin where there was significant herbicide damage that restricted lupin growth and its ability to compete with the main weeds at the site (Annual Ryegrass and Wild Radish). This result is in contrast to current grower perception of the efficiency of legume herbicide options currently available, and from similar trials in the West Midlands area. The difference between these earlier trials and this trial was in the use of best practice herbicide packages that were tailored to each crop species, as guided by Harmohinder Dhammu and Mark Seymour (2023) during the design stage of the trial. This has highlighted the importance for growers to seek qualified advice and consultants who have experience in growing these alternate legume crops, although lack of knowledge in herbicide use for alternate legume crops has been acknowledged. This trial can serve as a starting point for growers to tailor herbicide packages for their own situation, and it is recommended that growers take a long-term approach to growing alternate legumes such as chickpea as it can take 3 years to improve grain yield and management of chickpea.
The second highlight was the importance of using species-specific herbicide treatments as lupin, chickpea, and vetch are all susceptible to the effects of herbicide application from other packages. In particular, the use of a lupin herbicide package (Treatment 1 and 2) on chickpea or vetch, while not leading to outright failure, decreased biomass production and grain yield at the end of the season. The use of chickpea herbicide package on lupin did result in crop failure, although this is unlikely to be a scenario that growers could face as the most popular legume and herbicide package use is lupin. The use of post-emergent herbicides across all species tended to cause the greatest crop damage for all crop species, as indicated by the difference in grain yield (and variability) between Treatments 1-4 and 5-8. The difference between these groups of treatments was that the post-emergent herbicide was omitted from each package. It is important that when growers do trial a new legume such as chickpea or vetch that they ensure farm workers understand the importance of applying the correct herbicide to each crop type to avoid crop failure, especially from post-emergent herbicide application.
The third highlight in this trial was that chickpea with a best practice chickpea herbicide package (Treatment 3) resulted in effective weed control and achieved a grain yield of between 1.8 and 2.2 t/ha, depending on herbicide package used. This grain yield was lower than the range of lupin grain yield (excluding severe herbicide damage) but still achieved a high grain yield for a low rainfall year. This indicates that chickpea do have the potential to perform in the WA Wheatbelt with the current range of varieties and agronomic packages. In this trial, a late rainfall event of 36mm during flowering was too late to improve lupin grain yield but was ideal for chickpea flowering and grain fill in a decile 1 rainfall year. The elasticity of chickpea to take advantage of late seasonal rainfall has been shown in the region in many previous trials and can be further improved by the use of early and/or deep seeding.
Future activities in this project will focus on establishing demonstration sites to showcase the efficacy of species-specific herbicide treatments in grain legumes. The demonstration sites aim to support the broader adoption of diverse legume species by providing clear, evidence-based management strategies. This effort is expected to contribute to the diversification of crop rotations within Western Australian farming systems, enhancing their sustainability and resilience.
By Melanie Dixon, WMG Mixed Farming Systems Officer & Kate Parker, WMG Graduate Project Officer
The time between harvest and seeding is when sandy soils are most at risk from wind erosion and topsoil nutrient loss. As the effects of increased climate variability become more pronounced, growers are looking at stubble retention as a valuable tool in helping protect soils over the summer months. Crop residues left after harvest offer nutrients, carbon, and a protective ground cover that lowers the risk of wind erosion. However, when residue is high after above average seasons, increased stubbles can mean seeder blockages during an extremely busy period of the farming calendar. The Western Australian Government State NRM funded Stubble Management Project is investigating alternatives to burning stubble and looking to the benefits that leftover crop residue can provide.
Stubble contains significant nutrients, and the ideal situation is being able to return these nutrients back into the soil, reducing potential mineral fertiliser input in the subsequent season. Groundcover also assists in minimising wind erosion and protecting the nutrient rich topsoil, with a general rule of thumb being to maintain levels of groundcover at 50% or above. Burning not only eliminates all protective groundcover but also removes potential nutrient gain. Approximately 80 per cent of nitrogen, 50 to 80 per cent of sulphur and 40 per cent of phosphorus can be lost to the atmosphere from burnt cereal stubble, with additional phosphorus and potassium being lost in ash.
As part of the Stubble Management Project, six demonstration sites were established in 2023 across the Northern and Central Wheatbelt to investigate how standing stubble, incorporation and an application of biostimulant (nitrogen) would compare. The timing of site establishment was ideal as stubble load was high in 2023 after two consecutive above average crop years. While there was no significant difference found in weed establishment, plant growth or harvest yield across all treatments, regardless of site location, there was also no observed downside to retaining the stubble on each of the sites. There was a slight negative impact on groundcover in machinery incorporation treatments, but this was not shown post-harvest and does not appear to be a long-term effect.
As stubble amounts vary from year to year, it is beneficial to have a range of options available without needing to weigh up the potential consequences to yield. Growers can tailor their management strategy to suit their current system, crop rotation and available machinery. Crop residue can be preserved, either as left standing or through machinery incorporation if the amount of stubble would impact the efficiency of seeding. With increased stubble management options, growers can review their strategies season to season. One possible opportunity provided by the retention of stubble rather than burning, is a long–term focus on increasing productivity through improved soil health and groundcover.
The West Midlands Group will continue to monitor the six demonstration sites involved in the project throughout 2024. There will also be a series of events showcasing the demonstration sites, and for growers to discuss all things stubble management and crop nutrition. The first (free) event will be held on Tuesday, 9th April at the Dandaragan Community Recreation Club (DCRC), with more details available on the event page. Read the full 2023 Stubble Management Project Seasonal Update here, and to follow along with the project and for helpful stubble management resources, head to the project page.
By Melanie Dixon, WMG Mixed Farming Systems Officer
Potassium deficiency and its subsequent management is a topical issue in the West Midlands region as farmers continue to push deep sandy soils to their upper yield potential. At the 2022 GRDC Regional Updates in Moora, growers requested further research into K management, specifically regarding soil types, application rates, and the ability of certain plants to recycle potassium from deeper soil layers. Growers were keen to understand the optimal timing and method for potassium application, and potential yield loss from limited plant K uptake.
In response to the GRDC Regional Updates, the West Midlands Group (WMG) K Extension Project was initiated to investigate the potassium status of 10 paddocks across the region, with the goal of understanding current soil K levels to depth and evaluating whether current management practices were sufficient for crop growth and yield goals.
Key findings from the project in 2023
Adequate K Management: Deep soil testing and nutrient budgeting revealed that 70% of the paddocks tested had sufficient potassium levels for crop needs. This indicates that growers in the West Midlands region are managing their potassium nutrition budgets effectively, applying the right amount of potassium to meet the needs of their crops, ensuring optimal growth and yield potential.
Subsoil K Potential: The discovery of significant amounts of potassium in the subsoil was unexpected and highlighted an untapped resource that could support alternative fertiliser management. This subsoil potassium presents an opportunity for growers to utilise deeper soil layers to meet their crops’ K requirements.
Challenges in K Utilisation: Despite the presence of sufficient K in some cases, plant tissue testing showed low K percentages. Factors such as subsoil compaction and low soil moisture, particularly in a year of below-average rainfall, were identified as potential barriers to efficient K uptake by plants.
Serradella as a K Cycling Crop: Serradella was identified as a crop with the potential to cycle deep potassium, possibly reducing fertiliser requirements in subsequent seasons. However, its suitability is limited in cropping-only systems, suggesting that a more diversified approach to crop management may be necessary.
In 2024, WMG will focus on identifying plant species that can effectively recycle large amounts of subsoil potassium. The aim is to reduce the reliance on blanket fertiliser regimes, which can be both costly and environmentally unsustainable. By finding crops or cover species that can access deep potassium reserves and bring them closer to the surface, growers can potentially lower their fertiliser requirements in subsequent seasons. This approach not only enhances soil fertility but also contributes to the long-term sustainability of farming systems in the region. This strategy can also play a crucial role in risk management as it allows growers to adapt to fluctuating fertiliser market conditions and mitigate risks associated with price volatility and supply chain disruptions.
So far, the K Extension Project has shed light on the importance of effective K management for crop growth in the West Midlands region. By addressing the challenges and leveraging the opportunities identified, growers can optimise their potassium management strategies for sustainable and profitable farm management.
WMG will be holding a free crop nutrition event on Tuesday, 9th April, head to the events page for more details. To keep up to date with the K Extension Project as WMG explore effective K cycling through crop rotations strategies in 2024, head to the project page.
This closed invitation event was an opportunity for participants on the Evolving Soil Testing Project to share experiences of the project, compare soil testing results and ask questions to soil professional Joy Sherlock (Valle Agribusiness & Environmental Solutions), who had completed the soil testing, analysis, and reporting. Although it would have been possible to have one on one meetings between Joy and the individual farmers, multiple farmers that were engaged in the project suggested a small get together to share and examine their individual results and discuss future soil testing and farm management plans.
Initial Discussion – “Balarang East” Paddock
After driving together for a tour of Balarang East, the project participants each introduced their personal areas of focus for the Evolving Soil Testing Project followed by host Brendan Van Beek detailing one of his focus paddocks. Brendan was interested in what could be gained from a good pasture and grazing program on this paddock and how this would be reflected in annual soil testing results.
Balarang East paddock has highly variable soil types (sandy loams, gravel ridges and clay).
2022 Season (500ml annual rainfall) – sown Moby barley, Balancia clover, Arrowleaf clover, Hycon Rose clover, and vetch. This mix was sown at different seeding rates to accommodate the variable soil types within Balarang East.
2023 Season (200ml annual rainfall) – Moby Barley from previous season had established (poorly) but was quickly grazed out by sheep. Sown vetch, cubclover and Balancia clover again, but had missed the first rain of the season and struggle to establish these pastures.
The standout performer of 2022 was the Balancia clover.
Brendan and Murray Grey discussed the grazing value of vetch, and both believe that it is not grazed until later in the season.
Each farmer discussed different management strategies and seasonal observations, posing questions to each other, Joy and the WMG team in the paddock before heading back to the shed for the in-depth soil testing results discussion.
*Other project topic focus results and discussions can be found in the case studies available on the Evolving Soil Testing Project page.
In-Depth Soil Testing Results Discussion (In the shed)
Joy had put together a complete information pack for each participant, containing soil test results, interpretation guide, in-depth soil report and a series of case studies. These were shared amongst the group for some initial discussion before Joy ran through the interpretation guide on one set of results, followed by an in-depth look at each participants results. Highlighted below is a snapshot of some of the discussion points from the first of these in-depth sessions.
Balarang East Paddock
Soil testing was completed in Balarang East in 2022 and 2023 through different contractors. This brings a level of sampling variation and bias, and differences in soil analysis methodology that Brendan is aware of. It was also recognised this would bring some complexity in the ability to compare results. Brendan had hoped to see an increase in soil carbon and nitrogen from highly productive legumes. Although there was a nitrogen increase, it was not as much as initially expected. There was a suggestion that some nitrogen could be tied up with carbon in the soil and is not reflected in the testing results. Brendan and Will Browne discussed the Cation Exchange Capacity (CEC) results, and the practical ways farmers can influence this. Sandy soils will tend to have a low CEC. Adding clay was discussed as an effective amendment influencing the CEC and increasing soil fertility.
Brendan wanted to have a better understanding of the long-term effects of spreading pig manure over a continuous cropping paddock. Boxhall paddock isn’t the ‘top’ performing paddock on the farm but is a regularly productive paddock. The soil testing revealed zinc was present in excess, which Brendan suggested could be caused by the zinc used in pig medication. There was a discussion between the group about what a practical change on farm is, especially as farm scale increases. It can be difficult to change the management of a small area of the farm, particularly in scenarios when this change could be considered a ‘1%-er’. There was an imbalance in the ratio between fungi and bacteria populations and the group was unsure in how this could be manipulated. Joy suggested to think about creating an overall healthy soil environment so fungi and bacteria populations could thrive.
Once the group had completed the in-depth results discussion, farmer attendees all shared their future soil testing plans, for 2024 and beyond. All farmers agreed that they had evolved their soil testing practices and understandings but would not soil test and collect data simply for the sake of collecting data but wanted to continue to expand their understanding of their farming environment. Brendan and Will both suggested they were interested in increasing the depth of soil testing. Brendan in particular wanted to test prior to soil amelioration. Murray will continue to tie soil testing and plant tissue testing together in his pursuit to understand the nutrient cycling between soil, plant, and livestock in his farming system and to improve his knowledge of soil biology.
End of Day Quotes
“There has been gold in this session that everyone could learn from.” – Will Browne
“I feel you can ask any question in this environment…everyone is striving for the same thing during these sessions.” – Murray Grey
“It is easy to contribute and be involved in a small group.” – Brendan Van Beek
By Simon Kruger, WMG Project Communications Officer
Graham ‘Johno’ Johnson – Leearna Farm, Dandaragan
Opened up in the 50’s and cleared by his father, Johno took over Leearna Farm in the 80’s after the wool crash. The farm started conventionally with a focus on cropping and achieving higher yields but while yields were continually going up, inputs were also increasing. Around the 2000’s Johno made the decision to begin working towards a more ‘mixed’ farming system prioritising working with nature when yields started plateauing and the farm was having more issues with insects and diseases. Over the years Johno has worked ‘bit by bit’ to diversify his operation, with Leearna Farm continually evolving, now being 50% certified organic with a focus on diversity, long term sustainability and trying to keep away from the ‘nasties’.
Initial Discussion – Organic Operation
Leearna Farm has achieved 50% organic certification, primarily focusing on organic beef production with an expansion into organic lamb (Ultrawhite breed).
Breeding and Finishing: Calves are bred at Leearna and then moved to Dandaragan Organic Beef for finishing with the Cook family.
Quarantine and Organic Pastures: Upon arrival, animals undergo a 3-week quarantine period in designated paddocks before being introduced to certified organic pastures.
Calving and Herd Management: Replacement PTIC cows are brought in before the last trimester for calving. The cows never become organic certified. Only the calves grazed on certified organic land for at least the last trimester and all their life are eligible to be certified organic.
Rotational Grazing: Johno utilises rotational grazing, typically with a single large mob (ranging from 80 to 300 cattle) followed by sheep during the growing season. Sheep are particularly effective at eating radish that the cattle refuse to touch.
Soil Stewardship: Rotational grazing is employed not only for herd management but also to promote soil health. Johno is continuously seeking the best practices for sustainable land management and those that fit his system.
Paddock 1 – Turning Around a Challenging Paddock
Through dedicated effort and learning from setbacks, Johno has transformed one of Leearna’s worst paddocks into its best. This transformation required time and continuous adaptation. Each hurdle presented valuable learning opportunities for Johno.
Building with Treelines, Tagasaste and Perennials: In 2009 a single 95 Ha paddock was split into 4 cells with 30 m fenced treelines being planted to a large variety of trees and shrubs. Wide spaced Tagasaste with inter row perennial grasses was established inside the cells,
Managing Tagasaste: Tagasaste is cut back every 3-4 years to maintain its growth.
Addressing Sandy Soil Challenges: After initial setbacks with wind erosion stripping out the newly planted perennials, Johno incorporated 250t/ha clay, significantly improving soil stability and non-wetting. Then replanted perennials to avoid having bare areas.
Minimal Additional Inputs: Beyond the initial soil improvement with clay, there has been only one application of guano and lime since 2007.
Success Through System and Grazing: The combination of implementing a well-defined system and employing rotational grazing practices has been key to the paddock’s success.
Based on his experiences, Johno suggests the best success can be found in a 3-step system:
Invert: This initial step may involve disturbing the existing soil structure, potentially through soil amelioration or controlled grazing.
Stabilise: Incorporate organic matter and consider amendments like clay and guano, depending on needs and availability.
Sow: Once the soil is stabilised, introduce suitable pasture species, and implement a rotational grazing system.
Johno emphasises that this approach yields benefits beyond increased pasture production. The management has restored biodiversity, enhanced birdlife, and provided shelter for livestock.
Paddock 2 – First Crack at a Multispecies Mix
This section highlights Johno’s approach to utilising a 65-hectare paddock for lamb production with a multispecies pasture mix.
Paddock History and Preparation
The paddock was initially set up by using a knockdown, spreading crushed lime/dolomite, offset discing to incorporate and reduce non wetting.
The sowed multispecies mix included barley, lupins, wheat, cereal rye, clover, serradella, vetch, tillage radish, and forage brassica.
Planting and Grazing Strategy
The mix was sown relatively late in the season on June 30th at 60 kg/ha of seed and 80 kg/ha of guano.
No further inputs or sprays applied.
On September 23rd, 500 mixed sex lambs were introduced to the paddock. 200 wether lambs were drafted off at the end of November with an average weight of 60kg and carcase weight of 28.2 kg. The remaining lambs stayed on the paddock with very minimal lupin supplementation until 14th February when the dam water quality deteriorated.
The lambs displayed clear preferential grazing, with radish, brassica, lupin, and vetch being consumed first, followed by barley, wheat and finally the cereal rye.
Another paddock nearby was locked up and successfully harvested as mixed species seed for the following season to be sown in other paddocks.
Future Plans
The paddock will be left undisturbed this season to allow the multispecies mix to regenerate naturally, enabling Johno to assess its performance in the second year.
Key Takeaways
The lambs thrived on the diverse forage options provided by the multispecies mix.
The cereals, especially cereal rye played a crucial role in providing summer cover and soil stabilisation.
Maintaining a balanced ratio within the mix, with lower cereal content, is recommended to avoid dominance and ensure successful establishment of other species.
The success of this paddock allowed Johno to purchase an additional merino trade mob, demonstrating the positive impact of this strategy on farm operations.
By Melanie Dixon, WMG Mixed Faming Systems Officer
Key Messages
No clear differences between stubble management treatments for in-season biomass production and harvest yield.
Leaving stubble standing remains the simplest management option, in seasonally permitting conditions.
Background
Farmers across the Wheatbelt region of Western Australia require alternate strategies to manage the increased on-farm variability that accompanies a variable climate with reduced rainfall. In years where crop production is high, there is more crop stubble that forms a protective mulch layer over the soil, reducing soil water loss, wind erosion and contributes to maintaining soil carbon and nutrient levels. However, during dry years, particularly in canola and lupin crops, the amount of organic matter returning to the soil is severely reduced. To maintain optimal soil health outcomes, stubble management practices should be adapted to the season.
Methodology
WMG has collaborated with Corrigin Farm Improvement Group to establish six demonstration sites across the Northern and Central Wheatbelt region. The site layout is replicated at each of the demonstration sites (see Table 1).
Treatment #
Stubble Management Treatment
1
Standing stubble
2
Machinery Manipulation
3
Applied Bio-stimulant (UAN)
Table 1: Site Treatment Layout
There is a single application of each treatment at the beginning of the 2023 season before a return to standard management practices for the duration of the project. This includes crop rotation, inputs, and applications rates. Plant count, weed counts, biomass and yield measurements are recorded across 2023 and 2024 to compare each of the stubble treatment effects.
Results
In – season biomass production
Figure 1: In-season Biomass Production (kg/ha).
Across all sites, irrespective of crop species and region, there is no clear difference in average biomass (kg/ha) in stubble management treatment, as shown in Figure 1. Throughout 2023, there were no reported visual differences in crop production, which is also reflected in the data displayed in Figure 1.
A similar result is found when comparing the data via region (Central Wheatbelt and Northern Wheatbelt) and crop type respectively (Figure 2). Although there is an increased biomass production in Central Wheatbelt – Wheat, the similarities between stubble treatments remain.
Figure 2: In-season biomass production (kg/ha) through Region and Crop Type.
Figure 3 shows the individual site in-season biomass production, accounting for rainfall and soil type variability. Northern Wheatbelt demonstration sites are 1 – 3 (top row) and Central Wheatbelt demonstration sites are 4 – 6 (bottom row). There is clear variability between sites, particularly where Site 4 exhibits increased biomass production. As with Figure 1 and Figure 2, Figure 3 suggests no distinct difference between stubble management treatments for in-season biomass production.
Figure 3: Biomass Production (kg/ha) through Sites 1 – 6.Image 1: Biotimulant, control & machinery manipulation treatments (L-R) at Site 1 (Northern Wheatbelt) June 2023.
Yield
Figure 4 displays the yield data from the Northern Wheatbelt sites only. There are no clear differences in canola yield across the stubble management treatments. This aligns with Figures 1 – 3, where in-season biomass production remained consistent regardless of stubble management treatments. There are minor differences between yields at Site 2 – Wheat, where the machinery manipulation treatments yielded the highest. This result supported the host farmers prediction, where he had previously experienced increased yields in the season immediately following soil machinery manipulation. Visual differences at this site were also recorded in-season.
Figure 4: Harvest yield across sites 1-3 (Northern Wheatbelt).
Discussion
The results of the 2023 season have demonstrated no differences in crop production between different stubble management practices. Due to the nature of a demonstration trial rather than replication, associations between yield, in-season biomass production and stubble management treatments are not definitive.
There was an increased stubble burden across all sites after a high production 2022 season. The project was originally devised as an opportunity to investigate management of large stubble burdens in above average rainfall years, and low stubble cover in dry years. Multiple factors may have affected the efficacy of treatments in the 2023 season, including a low average rainfall across both regions. Expectations amongst treatments included applied biostimulant increasing stubble breakdown and machinery manipulation increasing stubble soil contact, although possibly increasing the occurrence of nutrient tie-up. These expectations were not met, with no differences recorded between treatments, leading to the conclusion that leaving standing stubbles remains the simplest management option. Multiple factors such as ease of seeding and increased time for biomass breakdown remain when leaving stubbles standing with no treatments, however results from the 2024 season may change this report’s initial observations.
Double break crop sequences can be more profitable than current canola-cereal sequences.
Early sowing can be a significant driver of profitability for chickpea, especially mid-April sowing.
Weed populations increased in the chickpea phase but did not cause issues in the following cereal crop.
Background
Break crops are widely acknowledged as being necessary to manage the biological constraints that reduce cereal crop production. However, one of the constraints in the use of break crops is that the Gross Margin of the commonly used break crops are generally less than growing a cereal crop. To combat severe biological constraints to crop production (high weed population and/or soil pathogens) break crops have traditionally been used as a single crop in rotation. The use of two break crops in sequence has been shown to improve the effectiveness of this approach, particularly as shifts in disease presence, and increases herbicide resistance in weeds has reduced the effectiveness of a single break crop. However, the use of break crops is limited to situations where the biological constraint has a greater impact on profitability relative to the lower profitability (Gross Margin) of the break crop.
The most desired traits of a break crop are to be highly effective in controlling weeds and soil pathogens while also being highly profitable. Current highly effective break crop options of canola and lupin are rated as moderate to low profitability (respectively) by growers, while pasture phases or fallow period generally result in a low or negative Gross Margin.
This study investigated the profitability of growing canola (with effective weed control options) followed by a high value legume (with higher economic value) as an effective and profitable double break crop sequence. The contribution of an early sowing date versus a traditional sowing date to further increase the profitability of the high value legume was also evaluated.
Methodology
The double break crop sequence was evaluated at 6 demonstration sites (no replication) over three years in the Western Australian Wheatbelt region. An existing paddock of canola or fallow (depending on rainfall zone) was selected to grow a high value legume and then follow this with a cereal crop on a wide range of soil types that are prevalent across the region. Crop growth was monitored along with grain yield, and the Gross Margin was calculated to give an overall return on the three-year crop sequence. Rainfall at most sites had a combination of a below and above average seasonal rainfall that impacted on the growth and grain yield of either the double-break crop or the following cereal crop, but not both.
Results
Figure 1. Cumulative Gross Margin over three years for each double-break crop rotation at each site compared to current practice (dark bars) in this study. Sites presented contained 3 years of data to include the first and second break crop, followed by cereal. Ca=Canola, Ch-L=Chickpea-Late sown, Ch-E=Chickpea-Early sown, L-L=Lentil-Late sown, AL=Albus Lupin, FP=Fieldpea, Fa=Fallow, W=Wheat, B=Barley, O=Oats.
There was large variation between sites for the Cumulative Gross Margin of the double-break crop sequence of Canola (or Fallow) followed by a legume and was reflective of the range of annual rainfall and grain yield potential for each site (Figure 1). Within each site, a strong trend was that the inclusion of a double-break crop led to a similar or greater cumulative Gross Margin over the 3-year period. Within the double-break legume phase, the early time of sowing tended to give an increase in grain yield for chickpea and this was a significant driver of the increase in Gross Margin. Some sites were discontinued after the high value legume year following poor crop growth and this resulted in a lower two-year Cumulative Gross Margin compared to growing wheat after a single break (data not presented).
Figure 2. Gross Margin of cereal crops following a double-break for all sites that completed the 3-year crop sequence. Dark bars denote current practice for each site. Sequence abbreviations: Ca=Canola, Ch-L=Chickpea-Late sown, Ch-E=Chickpea-Early sown, L-L=Lentil-Late sown, AL=Albus Lupin, FP=Field pea, Fa=Fallow, W=Wheat, B=Barley, O=Oats.
The was a trend that the Gross Margin of cereal crops was improved in the third phase of the crop sequence following a double break crop sequence (Figure 2). There was no consistent trend in the effect of time of sowing for chickpea on subsequent cereal grain yield, however, the Gross Margin and grain yield were increased by the preceding legume crop when the legume grain yield was low, independent of the time of sowing.
Figure 3. Comparison of early sown (left) versus late sown (right) chickpea at Wickepin on the 17th August, 2021. The alternate plot can be seen in each photo for reference as well as tree in left of both pictures. Photo: Amy Bowden (Facey Group).
There was also a trend that the total weed population in the third-year cereal or second-year legume were higher after the double break crop sequence compared to standard practice of growing two cereal crops following canola or fallow (when measured at GS.30 growth stage for cereals) (data not presented). The use of canola or fallow as the first crop in the double break sequence appeared effective at lowering weed numbers, while weed populations tended to be higher in the high value legume year. Weed control in the cereal crop year appeared effective in ensuring that weed populations do not get out of control as total weed population was around 50 plants/m2 for double break crop sequences.
The impact of double break crop sequences on the four main soil pathogens in WA was not clear in this study (data not presented). The level of soil pathogen varied between sites and years, with the major soil pathogens being P. neglectus and R. solani AG8. Within each site, there was evidence that each crop sequence had a greater impact on changing the relative proportions of soil pathogens rather than an overall reduction in pathogen levels. The structure of this study limited the collection of soil pathogen data prior to the double break being implemented.
Discussion
This study has shown that a double break crop sequence can be more profitable than a single break where a high value legume (chickpea) can be successfully grown across the Wheatbelt of WA. This was shown across a range of soil types and rainfall zones in this study, with a key outcome being that chickpea were successfully grown in soil types and regions that were not considered to be suited to growing this legume crop. The early seeding of a high value legume in Mid-April rather than Mid-May was an effective practice to increase grain yield and drive profitability of the legume compared to the late sowing timing for every paired sowing date. It appears that the potential for chickpea to be a profitable break crop is underestimated in WA with the current agronomy packages and genetic material available.
A double break crop sequence can be a profitable option for growers in the Wheatbelt region of WA to boost the both the following cereal crop and be profitable in each year of the crop rotation. This benefit to the productivity of cropping in this region is based on the amelioration and removal of soil constraints that have previously impeded the growth of chickpea on soils other than heavy clay types. Strategies have been employed by growers over the past 10 years to remove soil compaction (deep ripping), soil water repellence (rotary spading, mouldboarding), and soil acidity (lime application). The result is a soil that is no longer inhospitable for chickpea and lentil growth. It is, however, difficult to estimate the amount of land that has been effectively ameliorated in the past 10 years where all constraints are now removed. While the focus of soil amelioration has been on the impact of these practices on wheat production, perhaps the most significant benefit for grain production from the removal of soil constraints may be the ability of growers to now diversify their crop options to further improve profitability with a lower risk of failure. Through this study and other related projects, chickpea production on other soil types has been de-risked for adoption by the practice of early sowing, which has been shown to increase grain yield on a range of soils in the Wheatbelt region, from deep coloured sands to sandy loam and clay soils.
While by no means conclusive, the data collected in this study indicates that weed populations are likely to increase in the legume phase of the double break sequence, but this does not cause a weed ‘blowout’ in the subsequent cereal crop. A barrier to successful weed control was encountered in this project where we found very limited knowledge among agronomic advisors on how to successfully grow high value legumes, especially in applying effective herbicide packages using the new chemical options now available.
This project was a GRDC investment which was led by the West Midlands Group over the 2020-2022 period in collaboration with the Liebe Group, Facey Group, and Corrigin Farm Improvement Group. We thank all the growers who contributed to this project.
It is a really exciting time to be at the helm of WMG as we take the covers off a whole suite of innovation in the way we engage and deliver to our farming members. Read on to learn more about how WMG will be working with its farming community in 2024.
For the past three years, WMG has been focused on answering one question – How do we deliver the outcomes that we promise in our project applications? This has led us to tear apart the whole organisation and put it back together, piece by piece, in order to address this question. There are three key aspects of project delivery that we focus on, including activities, outputs, and outcomes, with each leading to the next in order to achieve what the project has been designed for. To achieve this, we have had to change the way we structure the activities and outputs of the organisation. Many of the tools that we needed to engage effectively with our farming community were already in use by WMG, but they needed to be trimmed and polished a bit to get them working better together. This restructure does have an impact (hopefully positive) on our farming community.
Activities are what we do in the field and are now focused on working with our farming members to trial and make an informed decision on whether or not to adopt a new practice or technology. You can read about this in other posts on the WMG website, but in essence, our role is to support farmers to work through the innovation and decide if it is right for them – not all practices or technologies are universally adoptable. We encourage our farming members to reach out with an idea or challenge to address – chances are that we have a project that you can slip straight into with other like-minded farmers.
Our outputs have two main focuses – they are what come from our on-ground activities.
We are engaging directly with our farming community through small group activities to facilitate information sharing in the region. My view has always been that if you want a problem solved, just get a handful of farmers in the room – their experience and know-how will soon find an answer. The calendar is being filled with a range of small group meetings during the year on a range of topics – we encourage all members to find the ones that resonate most with them and come along. This approach varies from the traditional grower group practice of having large, full-day events with multiple topics and speakers, and allows greater farmer engagement and discussion on a specific topic.
All the activities and outputs from WMG are now housed on the WMG website for each project, along with the latest news and calendar of events. I encourage everyone to take a look through the websites as there are some fun things to play with that have been scattered throughout the site. I would like to acknowledge WMG Extension Officers Simon Kruger for his massive efforts in developing this website, and Melanie Dixon for helping to get all of the project information up on the website. There is still way more information and innovation to find its way to the website, and we will let you know in due course when we do our updates.
To reflect the many changes in the organisation, there has been a restructure of our roles within WMG.
On a sad note, we recently said farewell to Michelle Johnson after nearly three years of service to WMG. Michelle has left a significant legacy in the organisation after helping to develop a lot of the back-end processes and frameworks that we need to be an efficient organisation, much of this won’t be visible to our members. We wish Michelle all the best in her future endeavours.
The remaining roles of WMG have been reclassified to better reflect where the organisation has grown to in the past two years. My role has now moved up to Chief Executive Officer to reflect the professional approach that the organisation and board have adopted, and in recognition of the depth and complexity of the process that we have in place across the organisation.
The roles of Communications and Project Officers has become quite blurry of late as we focus strongly on extension and now our on-ground team have transitioned to an Extension Officer role. Each extension officer has their specialisation, with Melanie focusing on data and project management and Simon on media and stakeholder engagement. We envisage that future Extension Officer roles will include other specialisations as the organisation and the needs of our members evolve.
Moving forward, the speed of change appears to be increasing as we complete many of our planned changes for this year. There are a number of posts on the website now that outline the process that has moved WMG to the strong position that we are now in. The capacity built in the organisation during this time will serve well into the future, but the way we have gone about innovating within the organisation will allow WMG to continue to evolve well into the future.
