Each year Summit Fertilizers processes thousands of soil samples from across WA. Samples are analysed by an independent laboratory, and the results help guide our clients to make more informed fertilizer decisions. They also provide us with valuable long-term information on soil health and nutrition trends. As our farming systems keep evolving, our soils too will continue to change in their condition and nutrient status.
In this spring newsletter we report on some of the noteworthy regional trends and nutrition updates, with a focus on:
pH;
phosphorus (P);
and, potassium (K) content.
North Midlands region pH
2023-24 topsoil and subsoil pH readings from the North Midlands shires of Mingenew, Three Springs, Carnamah, Coorow, Morawa and Perenjori are a good news story indeed! When compared to Summit samples taken back in 2014-15, both topsoil and subsoil pH have shown healthy improvement.
Most WA crop and pasture species have proven to perform best when topsoil pH is above 5.5 (in CaCl2) and subsoils above 4.8. pH values below these can reduce the availability of many soil nutrients and reduce root exploration via an increase in availability of the toxic form of Aluminium (Al).
Figure 1 clearly shows the benefit from investing in lime and soil amelioration in the North Midlands. Summit testing in 2023-24 showed 72% of North Midlands region topsoils sampled had pH above 5.5. That’s a significant improvement on the 43% from samples taken in 2014-15.
Midland region subsoils have likewise benefited with a similar trend.70% of the regions subsoils were measured with pH of above 5 in 2023-24, compared with 41% in 2014-15.Extensive amelioration programs would most likely have helped with this shift, by moving applied lime into the subsoil. Not only can improved topsoil and subsoil pH increase root exploration and the availability of most nutrients, it can enhance soil conditions to increase the survival of soil organisms such as bacteria, legume inoculum, and earthworms.
The data indicates many paddocks in the North Midlands region are now better placed than they were a decade ago to take full advantage of applied fertilizers and favourable seasonal conditions.
P & K
Critical soil test values for P and K are harder to determine as definitively as pH. Soil type, rainfall, crop or pasture type and other soil test parameters need to be considered along with pH, to build a more complete picture of P and K status.
North Midlands region Colwell P test results for 2023-24 are shown in Figure 2. Summit inSITE gives a “P status” indication that takes all soil test parameters into account to advise the likelihood of a response (or lack of)to P application.
Topsoil samples taken in the North Midlands region in 2023-24 showed close to 60% had Colwell P readings below 20mg/kg. It’s a surprising result given 2023 applied P was followed by such a poor growing season in the area. But, perhaps not surprising given the huge crops and nutrient removal in the previous years. Summit trials are continuing to evaluate the new DGT-P test as a potentially better method than the Colwell P test for identifying responses on soils with a PBI > 30.
Figure 3 shows topsoil and subsoil K results. We know how difficult it is to increase soil K on very sandy soils. The best strategy on these soil types is to apply K until you get to a stage where responses are less visible/common. In-season Summit K gauges can help assess your K status. Plant testing can also provide valuable insight.
Key messages
North Midlands region growers should continue to keep an eye on nutrient removal. Make sure areas that test low in plant available P are addressed and rates are in balance with yield potential.
Maintain a replacement strategy on sites that have adequate P. Nutrient removal calculations area good way to get an overview of what you are exporting. Post-harvest calculations will help fine tune your rates so you can adjust your fertilizer order accordingly.
Lastly, have a long term-nutrition vision. You would want to be in the position in five or ten years time whereby soils still have healthy pH and, P and K levels are not limiting farm production.
In 2024, one of our primary trial sites has been Tim Creagh’s gravel soil paddock in Dandaragan. Tim, alongside the West Midlands Group (WMG), has been investigating how various soil amelioration methods can combat increasing water repellence in his gravel soils as part of the GRDC funded Soil Water Repellence Project. Four different methods have been tested this year: inversion tillage with a Plozza Plow, deep ripping with delving plates (Nufab deep ripper – both single and a double pass), and mixing and delving with the Plozza ‘Fanger’. While the main focus of this GRDC-funded project is to address soil water repellence, it also provides valuable insights into how these techniques influence nutrient uptake.
Visual differences in treatments at the Soil Water Repellence Project Dandaragan trial site.
Impact of Soil Amelioration on Crop Nutrition
Recent research (Scanlan 2024) from various sites across Western Australia (including Wathingarra, Dandaragan, Badgingarra, and Regans Ford), has shown that mechanical soil amelioration significantly impacts crop nutrition and fertiliser management. Techniques like deep ripping and rotary spading can enhance nutrient availability by redistributing nutrients within the soil profile and improving root access to previously unavailable nutrients. This can increase crop yield potential, but it also means that fertiliser application rates may need to be adjusted to meet the increased crop nutrient demands. Preliminary findings suggest that ameliorated soils respond better to fertilisers, particularly nitrogen, which can lead to improved crop performance and profitability. Ongoing studies aim to develop specific fertiliser guidelines for ameliorated soils, considering the spatial variability in nutrient distribution and ensuring optimal nutrient management (Scanlan 2020). Additionally, research into plant responses to nutrient applications post-amelioration is providing valuable insights into long-term fertiliser strategies. These insights emphasize the need for tailored fertiliser management practices to maximize the benefits of soil amelioration.
Effect of Amelioration on Specific Nutrients
The impact of soil amelioration on nutrient availability varies across different nutrients (Bryce, Plusky 2022). Here’s a summary table of how mechanical amelioration can affect key nutrients:
Nutrient
Impact of Mechanical Amelioration
Nitrogen
Release of Nitrogen: Mechanical amelioration techniques can promote the release of nitrogen from organic matter through increased aeration and better soil structure. Methods like deep ripping or mixing stimulate microbial activity, breaking down organic matter and releasing nitrogen in plant-available forms like nitrates and ammonium. While this can improve nitrogen uptake, there is a risk of volatilisation and leaching, especially in sandy soils.
Phosphorus
Limited Impact on Phosphorous Availability: Unlike nitrogen, phosphorous is less mobile in the soil and therefore less affected by soil disturbance. It tends to form insoluble compounds with calcium, magnesium, and iron in the soil, making it less available to plants. Therefore, mechanical amelioration may have a limited effect on increasing phosphorus availability, especially in soils that are already high in calcium or iron. However, there can be a risk of increased phosphorus loss via runoff if not managed appropriately.
Potassium
Improved Potassium Availability: Potassium, like nitrogen, is a mobile nutrient that can be affected by mechanical amelioration. The process of tillage or deep ripping can enhance the mixing of soil layers, improving the availability of potassium in the topsoil. It can also improve root penetration, which helps crops access potassium more efficiently. However, as potassium is a mobile nutrient, mechanical amelioration can also increase risk of it leaching deeper into the soil profile, out of reach of plant roots.
Sulfur
Sulfur Release from Organic Matter: Sulfur is often found in organic forms that require microbial activity to convert it into plant-available forms (sulfates). Mechanical amelioration, such as tilling or mixing, can improve microbial activity in the soil, thereby increasing the rate at which sulfur is mineralized and made available to crops. However, like nitrogen, this process comes with the risk of sulfur leaching.
2024 Trial Results
Nutrient levels (Nitrogen, Phosphorus, Potassium, and Sulfur) were analyzed in two ways: kg/ha and percentage composition. The kg/ha of nutrients is calculated by overlaying the percentage uptake with the amount of biomass produced at each sampling stage. Kg/ha indicates the physical amount of nutrients taken up from the soil and any fertiliser applied whilst percentage uptake helps determine if a crop is deficient in any nutrients.
Figure 1. Nutrient uptake kg/ha for Nitrogen, Phosphorous, Potassium and Sulfur for all treatments. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
Figure 1 shows the nutrient uptake in kg/ha for nitrogen, phosphorus, potassium, and sulfur across all treatments. The data indicates that at Growth Stage 30 (GS30), all ameliorated treatments had higher nitrogen uptake than the control, with the Fanger, Nufab, and Nufab double pass treatments showing the most significant differences. At peak biomass, ameliorated treatments still had higher nitrogen levels, with the Fanger treatment showing the largest difference. For phosphorus, there were no significant differences between treatments. Potassium uptake was significantly higher in the Plozza Plow and Nufab double pass treatments at GS30, but by peak biomass, differences were deemed not significant. This means that although visually the graph shows large differences between the control and ameliorated treatments, there was a high level of variability in the results leading to the error bars overlapping. Sulfur levels at GS30 were significantly higher in the Nufab single pass treatment compared to the control, and at peak biomass, both the Fanger and Nufab single pass treatments were significantly higher than the control.
Figure 2. Nutrient percentages for Nitrogen, Phosphorous, Potassium and Sulfur for all treatments. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
Figure 2 shows the percentage composition of nutrients for each treatment. The only differences observed were at GS30 for Nitrogen and Sulfur. This means that for the insignificant results in the phosphorous and potassium graphs, the differences seen in kg/ha graphs (Figure 1) are due to differences in biomass production. The Fanger and Nufab double pass treatments showed the most notable differences for nitrogen and sulfur, indicating that these amelioration methods may enhance nutrient uptake, particularly at early stages of crop growth. Although visually the graphs for potassium seem different, there was high variability meaning any differences are not significant.
Discussion
While some ameliorated treatments showed improvements in nutrient uptake, particularly for nitrogen and sulfur, the variability of results suggests that further research is needed to better understand the long-term effects of these methods on nutrient availability and crop performance.
Assumptions about amelioration would be that increased nutrient uptake and percentages would mean a decreased need for fertiliser. This may be untrue, with amelioration just moving the bar up for yield potential leading to a possible increase in fertiliser needs to get the highest potential out of the ameliorated soils. Mechanical amelioration methods can significantly influence the availability of nutrients in the soil by improving soil structure, enhancing microbial activity, and facilitating nutrient release. The impact varies for each nutrient:
Nitrogen and sulfur are more likely to show positive responses due to increased microbial activity.
Phosphorus and potassium responses are more complex and depend on soil conditions.
These nutrient interactions are reflected in the results (Figure 1 and 2), with nitrogen and sulfur showing the most significant differences in nutrient uptake between ameliorated treatments and controls, while phosphorus and potassium exhibited smaller differences. This raises the question: if crops are taking up more nitrogen and sulfur, should fertiliser application rates be reduced, or will increased crop and root growth necessitate more inputs? Similarly, with increased yield potential, does this mean that higher proportions of phosphorus and potassium are needed, or would this be less effective due to the low response?
It is also important to consider the potential for soil depletion. Increased nutrient uptake from amelioration could deplete soil reserves, potentially putting the paddock at a disadvantage in future seasons. With amelioration improving nutrient availability, it is essential to ensure there are sufficient nutrients in the soil to support enhanced crop growth without depleting key resources.
The effectiveness of these amelioration methods on nutrient availability depends on the type of amelioration, soil type, and timing of fertiliser application. To optimise nutrient use, farmers should carefully select and manage mechanical amelioration techniques based on their specific soil conditions and crop requirements.
Key Takeaways for Growers
Enhanced Nutrient Uptake: Improved nutrient uptake has been observed for Nitrogen and Sulfur in ameliorated treatments which can increase yield potential, but may also require higher fertilizer inputs to support increased crop growth.
Soil Health Management: Effective soil amelioration can improve soil structure and water infiltration, but care should be taken to avoid soil compaction and erosion.
Nutrient Management: Understanding the mobility and availability of different nutrients is crucial for optimizing fertilizer use and minimizing losses through leaching or erosion.
Tailored Approaches: Each soil type and condition, alongside seasonal factors may require a tailored approach to soil amelioration. Regular soil testing and monitoring can help in making informed decisions on fertiliser application and soil management.
Continued investigation: Further research is needed to better understand the long-term effects of these methods on nutrient availability and crop performance.
Conclusion
In conclusion, the 2024 trial at Tim Creagh’s gravel soil paddock in Dandaragan highlights the significant potential of mechanical soil amelioration methods in enhancing nutrient uptake, particularly for nitrogen and sulfur. While the results so far show promising improvements in nutrient availability, the variability in responses across different treatments underscores the importance of further research. As soil amelioration techniques continue to evolve, understanding the long-term effects on both nutrient management and crop yield potential will be essential for farmers. Continued trials for this project on different soil types are already in the works for the 2025 season. Whilst the focus of this project is Soil Water Repellence, the data of increased nutrient uptake from soil amelioration can assist in enabling more precise recommendations for managing soil health and optimizing fertilizer use to ensure sustainable and profitable farming practices in the future.
References and More Information
Adesanya, T. et al. (2024) ‘Crop rotation diversity and tillage effects on soil and wheat grain nutrient concentration in an organically-managed system’, Journal of Agriculture and Food Research, 18, p. 101411. doi:10.1016/j.jafr.2024.101411.
Angon, P.B. et al. (2023) ‘An overview of the impact of tillage and cropping systems on soil health in agricultural practices’, Advances in Agriculture, 2023, pp. 1–14. doi:10.1155/2023/8861216.
Manhas, S. et al. (2024) ‘Assessing the impact of tillage practices and nutrient levels on the growth and productivity of ethopian mustard (brassica carinata L.) – soybean (glycine max (L.) merr.) cropping system’, BMC Plant Biology, 24(1), pp. 24–1059. doi:10.1186/s12870-024-05753-7.
Singh, D. et al. (2020) ‘Effect of reversal of conservation tillage on soil nutrient availability and crop nutrient uptake in soybean in the vertisols of Central India’, Sustainability, 12(16), p. 6608. doi:10.3390/su12166608.
Young, M.D., Ros, G.H. and de Vries, W. (2021) ‘Impacts of agronomic measures on crop, soil, and environmental indicators: A review and synthesis of Meta-analysis’, Agriculture, Ecosystems & Environment, 319, p. 107551. doi:10.1016/j.agee.2021.107551.
In the West Midlands region farmers face significant soil challenges, including water repellence, nutrient leaching, and low nutrient levels. These challenges are largely due to soils with low clay content and organic carbon, which contribute to poor nutrient and moisture retention, impacting both soil structure and fertility. To address these issues, local farmers are adopting next-generation soil amelioration tools and organic amendments to enhance soil fertility, increase soil carbon levels, and improve overall resilience—particularly in sandy soils.
The Future Carbon Project, funded by the Department of Primary Industries and Regional Development (DPIRD) and the Soil CRC, has been a pivotal project running for over four years. This long-term study and Wathingarra Road trial site evaluates the effectiveness of various organic amendments in improving soil organic matter and explores combinations of amendments and amelioration techniques to identify potential synergies. The goal is to achieve long-term benefits for soil health, carbon levels, and crop yields.
Future Carbon Project Wathingarra site farmer discussion event held in August.
In August, a group of 20 local farmers and agricultural industry representatives visited the Future Carbon Project trial site at Jeremy Roberts’ property in Badgingarra as part of a West Midlands Group (WMG) crop walk. Attendees reviewed key results from the trial and discussed practical applications of soil amendments and amelioration methods. Questions were raised about the specific amendments used and their mechanisms. This article provides an overview of the amendments trialled, including Ironman Gypsum, Compost – Humicarb, Biochar, and Frass.
What are soil amendments?
Soil amendments refer to organic or inorganic substances incorporated into soil to enhance its quality and support plant health. Their primary purpose is to modify the soil’s chemical, physical, or biological properties, thereby mitigating limitations or improving its overall functionality. Various amendments are tailored to address the unique requirements of specific soil types and plant species. For instance, materials like gypsum and lime alter soil characteristics, whereas compost and worm castings function as soil conditioners by enhancing its physical structure.
Ironman Gypsum
Ironman Gypsum is a secondary product derived from titanium ore processing, specifically a pelletised by-product of mineral sands processing. The material is a neutralised acid effluent stream from the leaching of iron-rich ore with sulfuric acid, which precipitates to form gypsum containing iron and manganese. This amendment offers a high sulfur content, high phosphorus absorption, and water retention capacity, and acts as a soil pH adjuster. Ironman Gypsum also enhances soil structure, boosts microbial activity, and contributes to nutrient retention. It has proven to be particularly effective in improving soil fertility and preventing phosphorus leaching, with implications for long-term soil health.
Compost – Humicarb
Humicarb compost is made from organic materials such as green waste, food waste, and animal manures, undergoing controlled aerobic composting to become a valuable source of carbon. This product plays a vital role in improving soil structure by stimulating aggregate formation, which enhances nutrient, water, and oxygen availability to plants. Additionally, it boasts high cation exchange capacity (CEC), helping soils store and release nutrients efficiently. Humicarb compost buffers pH and salt fluctuations, optimising soil chemistry for better nutrient efficiency. It is particularly beneficial for boosting microbial activity and promoting plant growth, as well as improving soil resilience to abiotic stresses and pathogens.
Biochar
Biochar is a stable, carbon-rich material created by heating organic material, such as crop residues, wood, or manure, in a low-oxygen environment. This process, known as pyrolysis, results in a product that enhances soil fertility by improving water retention, soil structure, and microbial activity. Biochar has several benefits, including increasing nutrient availability, raising soil pH, and mitigating climate change by sequestering carbon. It is also effective in remediating soil pollution, including organic pollutants and heavy metals. However, the effectiveness of biochar depends on the specific production methods, and different types of biochar may be selected based on soil and crop needs. While biochar’s long-term benefits are clear, there is a need for further research on its impact over extended periods in the field.
Frass
Frass is an organic fertiliser produced by the larvae of the Black Soldier Fly (Hermetia illucens), which feed on organic waste. This nutrient-rich by-product is gaining popularity for its ability to improve soil health and contribute to the circular economy by recycling organic waste. Frass provides essential nutrients, particularly nitrogen, which are readily available to plants. Additionally, it introduces beneficial biomolecules and microorganisms that promote plant growth, increase resistance to pests and pathogens, and enhance tolerance to abiotic stresses. Its application can support sustainable agriculture by improving soil fertility and reducing the environmental footprint of waste disposal. Since it has diverse biochemical properties influenced by various production and environmental factors, further research is needed to evaluate its potential for extensive use in crop production and agriculture.
Future Carbon Project site soil amendment properties
Properties
Ironman Gypsum
Compost
Biochar
Frass
pH (CaCl2)
8.0
7.0
7.1
7.7
Electrical conductivity (dS/m)
3.09
7.6
0.53
2.19
Organic carbon (g/kg)
5.5
51.6
>99.5
93.7?
NH4-N (mg/kg)
<1
167
3
5488.33
NO3-N (mg/kg)
10
37
6
7.19
Colwell P (mg/kg)
8
952
117
5616.15
Colwell K (mg/kg)
61
8974
359
5887.77
S (mg/kg)
13274
6501
111
3690.84
B (mg/kg)
0.73
6.40
<0.10
0.88
DTPA Cu (mg/kg)
1.10
11.6
3.56
0.88
DTPA Fe (mg/kg)
52.0
41.4
16.6
28.76
DTPA Mn (mg/kg)
20.9
117
3.72
0.40
DTPA Zn (mg/kg)
0.34
151
16.5
6.07
Ex. Ca (cmol(+)/kg)*
77.1
73.9
7.23
1.2
Ex. Mg (cmol(+)/kg)*
8.74
17.0
1.41
2.9
Ex. K (cmol(+)/kg)*
0.10
21.4
0.78
15.1
Ex. Na (cmol(+)/kg)*
0.85
12.0
0.56
6.5
Phosphorus buffer index (PBI)
6650
137
59.4
–
*Exchangeable cations (not pre-washed). Note: Frass PBI not recorded.
Frass and Biochar spread on a plot at the Wathingarra Future Carbon Project site.
Conclusion
Soil amendments play a critical role in improving soil health and boosting agricultural productivity, particularly in regions like the West Midlands where soils face unique challenges. The amendments trialled in the Future Carbon Project – Ironman Gypsum, Humicarb Compost, Biochar, and Frass – each look to provide valuable benefits, including enhanced soil structure, increased nutrient availability, improved water retention, and greater plant resilience.
By exploring these innovative tools and understanding their unique properties, farmers can make informed decisions about the most effective solutions for their soils. Continued adoption of soil amendments may contribute to healthier, more resilient soils and sustainable agricultural systems across the West Midlands region.
Through the insights already gained and ongoing research, the Future Carbon Project is helping expand our understandings and knowledge of novel amendments to address soil challenges and build sustainable agricultural systems for the future. Find out more about the project on the project page, or join a farmer discussion group to get involved.
This project is supported by the Western Australian Carbon Farming and Land Restoration Program, The CRC for High Performance Soils (Soil CRC), and Future Green Solutions.
The FEED365 Project is wrapping up its third year, focusing on developing pasture management strategies that ensure year-round feed availability while reducing reliance on supplementary feeding. The West Midlands Group (WMG) has partnered with two producers at Warradarge and Gillingarra to trial solutions for addressing early winter and late spring/summer feed gaps. These trials explore a combination of pasture and cropping systems to improve livestock feed supply throughout the year.
Growers have faced significant challenges this season, including a particularly dry start and below-average rainfall during critical growing months. Rainfall data from Badgingarra Research Station highlights the difficult conditions, with 2024 totals sitting below the long-term average (533.4 mm).
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
2024
0.0
5.8
5.2
4.8
38.2
104.2
158.4
86.4
9.6
40.0
14.8
6.2
473.6
LTA
10.6
15.4
15.4
25.9
66.2
97.3
102.7
84.7
47.4
26.4
17.7
8.6
533.4
Table 1. Rainfall (mm) for 2024 at Badgingarra Research Station.
This seasonal challenge has emphasised the importance of flexible grazing strategies to maintain feed continuity. At the Warradarge site, the focus has shifted from in season grazing towards whole crop grazing at the end of season to make the most of available resources. Meanwhile, at Gillingarra, mixed pasture systems are being tested to address feed gaps later in the season.
At the Warradarge site, where crops advanced rapidly to head, opportunities for pre-growth stage 30 grazing were limited. In response, the site adopted a form of a “Grain and Graze” strategy, exploring the potential of grazing crops as livestock feed. A traditional grain and graze system would be to graze crops before growth stage 30 and then to harvest grain as normal; the strategy currently being implemented at the Warradarge site is a further exploration of this, looking into the potential for grazing whole unharvested crops. Research is limited on this adaptive strategy with most information on late season grazing being on failed crops or stubble. The FEED365 project will investigate the potential of this novel strategy to give farmers more options late in the season.
The serradella and barley paddock at the Warradarge FEED365 site.
A mob of sheep is currently grazing an unharvested barley and serradella paddock, which recorded an average pre-graze biomass of 3911 kg/ha of dry matter. Lamb weights were recorded prior to grazing, and will be tracked at 3 and 6 weeks to measure weight gains over the period. Once grazing on the barley concludes, the sheep will move onto an unharvested triticale paddock for further monitoring. Early indications suggest whole crop grazing could offer benefits such as reduced supplementary feed costs, efficient crop biomass utilisation, and improved soil cover—though careful management is needed to avoid risks like acidosis and soil erosion.
At the Gillingarra site, the trials have focused on combining annual and perennial pasture species to extend grazing opportunities and build system resilience. By integrating species such as lupin, vetch, and barley into existing perennial grass pastures, the site aims to provide reliable late spring and summer feed options. Results so far show promising improvements in pasture production and feed availability, offering a flexible solution for addressing seasonal feed gaps.
The cover cropped perennial paddock at the Gillingarra FEED365 site.
As the FEED365 Project enters its final stages, WMG will continue monitoring livestock performance at both sites over the summer, while analysing the economics of 3 years worth of data collected over the projects lifetime. The preliminary findings demonstrate that whole crop grazing and cover cropping systems can play a critical role in reducing feed costs, increasing animal performance, and addressing seasonal challenges when managed effectively.
Looking ahead, WMG will share further results from the summer grazing trials early in the new year. A farmer discussion event will provide an opportunity to explore the economics of the FEED365 demonstration sites, comparing livestock performance, pasture production, and financial outcomes of different treatments. Stay tuned for event details and more insights into the future of sustainable grazing and pasture systems.
Further Reading
For more information on the Feed365 Project and useful technical information, explore the following resources:
As the year comes to a close, it’s a great time to look back on what we’ve achieved in our businesses and organisations. It’s also a chance to reflect on the challenges we’ve faced and grown from, as well as to take a moment to appreciate the good things that have happened – something we often overlook when life gets busy.
For WMG, this year has been a standout. From my perspective as CEO, it’s been the most successful year in my seven years with the organisation. What’s stood out the most is how we’ve transitioned to a more sustainable and profitable business model. While we’re a not-for-profit organisation, it’s vital to ensure we’re financially stable, and this year marked the end of a three-year journey of making changes that have had a massive positive impact.
One of the big decisions we made was to take Seasonal Updates and Spring Field Day events off the calendar. These events, while valuable in the past, had become costly to run and weren’t attracting as many people as they used to. We’d also consistently heard feedback that it was hard to cover everyone’s favourite topics, as we tried to cater to a broad range of interests like cropping, pastures, grazing management, sheep, cattle, and backgrounding.
Instead, we’ve focused on running smaller, discussion group-style events that allow us to dive deep into a single topic over a few hours – often with a beer or two to keep things relaxed! The response has been fantastic, with participants highly engaged and giving us excellent feedback. This format builds on our first event of this kind, which we ran back in 2021 as part of the BeefLinks Backgrounding Project.
The WMG Team with Dr Hanabeth Luke (left) at the 2024 Soil CRC Conference in Wagga Wagga
In terms of numbers, we’ve engaged with about 229 farming participants both this year and last. But this year, we delivered this through 16 discussion group events, many of which wrapped up with a sundowner where everyone could catch up and socialise. It’s been great to see farmers coming to multiple events and building connections with each other – the sense of community has really grown with this new approach.
We’ve also changed how we communicate and share information. We now publish fewer social media posts each week, but each one is carefully crafted to provide what we like to call a ‘nugget of gold.’ This change was driven by feedback from farmers who told us there’s just too much information out there, and it’s hard to find the good stuff. On top of this, all our research articles are now published on our website, making them available anytime our community needs them. It also helps us see which articles are the most popular so we can deliver more of what farmers want.
Behind the scenes, WMG has been working hard to develop new tools and approaches to better support our members. This has helped us deliver valuable information and advice while keeping things running smoothly with our small but dedicated team. We’ll continue refining and improving into 2025, with plans to make our discussion group events even better at bringing producers together and delivering value.
I’m incredibly proud of what our small team of three has achieved this year – it’s easily been our most productive year yet. I also want to thank all our members for their amazing support. It’s thanks to you that we’re able to keep supporting the sustainable growth of agriculture in our region.
On that bright note, I wish you all a safe and happy festive season. I can’t wait to see you in 2025!
Grain growers across Western Australia are well aware of the importance of potassium (K) as a key nutrient that can limit grain yield potential, particularly in sandy soils. To better understand this issue locally, a crop nutrition survey was conducted as one of the first steps of the GRDC funded K Extension Project in 2023 to assess the potassium balance of 10 paddocks on a variety of soil types. Two key findings emerged:
Significant amounts of potassium were present in the subsoil at most sites, suggesting that crops could benefit from accessing a larger volume of soil for potassium.
Current fertilisation practices on these paddocks were insufficient to meet the potassium removal rates expected from crops, underscoring the need to adjust fertiliser strategies to ensure adequate potassium availability for optimal crop growth.
Building on these findings, WMG has been investigating the ability of five different crop species to access potassium from deeper soil layers to recycle K up to the soil surface. As a side investigation, this site also includes the impact of early post-emergent deep ripping on crop growth and the availability of K in the soil profile.
Figure 1. The K Extension Project Yathroo site.
The Yathroo site (Figure 1) is a replicated trial with duplicate treatments for +/- early post-emergent deep ripping to 60 cm. Five crop species were grown in each scenario, including short and medium season wheat, lupin, canola, and serradella. The potassium levels in each crop were sampled at the start of stem elongation (GS30, 6/8/24) for cereals and canola, at the start of flowering for lupin and serradella (17/9/24), and again at maturity for serradella (24/10/24). The aim of this trial was to determine the amount of potassium (kg/ha) contained in the plant biomass produced by each crop to understand the ability of each crop species to recycle potassium.
Figure 2. Potassium uptake kg/ha at peak biomass and End of Season (EOS) for all crops (left) and the ripped and non-ripped aggregated treatments at the Yathroo site in 2024. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
Potassium uptake was greatest in the mid-season wheat (Wheat-M) and lowest in the serradella treatments for both wheat anthesis and end-of-season timing for serradella (Figure 2). Canola and lupin were intermediate in their uptake of K compared to all other crop species. The impact of deep ripping on K uptake was significant, with ripped treatments generally having approximately 20 kg/ha more potassium in plant biomass than unripped treatments (Figure 3).
Figure 3. Visual differences in crop height between the non-ripped (left) and ripped (right) treatments at the Yathroo site.Figure 4. Biomass at peak biomass and End of Season (EOS) for all crops (left) and the ripped and non-ripped aggregated treatments at the Yathroo site in 2024. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
The same trend for potassium uptake was evident in the biomass production for each crop species, where mid-season wheat had the highest biomass and serradella had the lowest biomass (Figure 4). Canola and lupin again had intermediate biomass production; however, lupin biomass production was similar to short-season wheat (Wheat-S). There was also a significant effect of deep ripping on biomass production, with all ripping treatments having higher biomass than non-ripped treatments. This confirms that there is a strong relationship between plant biomass and K uptake (R²=0.81), indicating that about 80% of the variation in K uptake can be explained by the variation in biomass production (Figure 5).
Figure 5. Relationship between plant biomass and Potassium (K) uptake across all treatments at the Yathroo site in 2024.
This study has found that the uptake of potassium in the soil is not directly related to the crop species but rather to the amount of biomass produced by each crop during the season. Any crop that can maximise biomass production in a given year is likely to maximise the uptake of K from the soil, particularly from deeper layers, and recycle this back to the soil surface. K recycling can also be influenced by other factors, such as deep ripping where crops can better access subsoil layers, or the length of the growing season.
Our understanding of K recycling at this site is limited to the total amount of K uptake by crops, as more accurate estimates of K uptake from each soil layer (particularly deeper layers) were not individually measured. From the K balance survey in 2023, it was known that the site had a low amount of potassium in the 0-30 cm layer and greater levels in the 30-90 cm layer, suggesting that most of the potassium taken up is likely to have come from the deeper soil layers to satisfy crop needs.
Wheat is known to be a high biomass crop and often contributes a significant amount of stubble to be recycled back into the soil. This is the main pathway through which most of the potassium taken up by the crop returns to the soil. In reality, much of the potassium in the stubble is contained in the plant cells as soluble potassium, which is easily leached out with significant summer rainfall (>15 mm). This highlights the importance of spreading stubble at harvest across the full harvest width to ensure that potassium is returned in an even distribution across the paddock for future crop use.
Deeper-rooted crops like canola, lupin, and serradella did not appear to bring up more potassium compared to wheat. Surprisingly, serradella performed poorly in terms of bringing up potassium from the soil in plant biomass, despite its reputation for effectively doing so due to its deep root system. In this study, serradella did exhibit a high percentage of K concentration compared to other crop species but this appeared to have little impact on K recycling (data not presented). Serradella has also been noted as being less efficient at accessing soil K in deep sandy soils compared to a shallower duplex soil. This study highlights that while serradella has the potential to increase potassium levels at the soil surface through its biomass, its effectiveness is largely dependent on achieving good biomass production. It should be noted that serradella’s ability to uptake potassium was limited by the low plant populations typically observed in the first year, with better results expected in the second year. The season was also very short, with the season break occurring on 1 June and the trial site being sown on 7 June, and a dry spring period (data not presented) limiting serradella growth at either end of the season. Future work comparing regenerating serradella to annual crop species would provide a better understanding of potassium uptake.
If you’d like to learn more about the overall purpose and aim of the K Extension Project click here.
If you’re looking for an in-depth look at the topics discussed at the Yathroo site crop walk, check out the WMG Farmer Summary here.
If you’re interested in getting more information on crop nutrition, workshops and related events click here.
In 2024, one of our primary trial sites has been located on Tim Creagh’s property in Dandaragan on a shallow sand over gravel duplex soil. This site has been exploring how various soil amelioration techniques can help address the increasing water repellence on gravel soils. The trial includes four different amelioration methods: inversion tillage using a Plozza Plow, deep ripping with delving plates (Nufab deep ripper – both single and double pass), and mixing and delving with the Plozza ‘Fanger’. These strategies have three primary benefits to the soil: inversion or mixing of the soil to reduce soil water repellence, mixing of nutrients and amendments deeper in to the soil profile, and removal of soil compaction. Following the amelioration treatments, the site was sown to oats with the option of harvest for grain or cut for hay.
While the main goal of this GRDC-funded project is to explore new strategies for mitigating soil water repellence, it also provides valuable insights into the impact of these amelioration techniques on dry matter production of various crops which can be used as forage crops and hay. This article explores the potential benefit that soil amelioration can have on soil strength and crop biomass production, and how this could benefit a grain-and-graze, cereals-as-pasture, or hay production system.
Managing soil water repellence is a key strategy in our region to increase crop growth and grain yield. Due to the relative stable relationship between the two (i.e. the harvest index), grain yield and crop growth are generally aligned meaning that high yielding crops tend to also grow a lot of biomass. This increase in biomass creates an opportunity for multiple uses, such as grain-and-graze systems that provide additional sources of income from the crop and benefits for the livestock enterprise. Recently, there has also been an increase in the use of cereals as pasture species across the West Midlands region as they have higher biomass production compared to other pasture species and addressing soil water repellence can have direct pasture benefits as well. If crop and pasture production can be maximised by addressing soil water repellence, crop yields can be higher and more feed can be grown to support a larger number of stock, enhancing the overall productivity of the farm.
In the short term, we know that tillage can lead to a noticeable increase in plant biomass because it helps break up the soil and makes it easier for plants to establish themselves and grow. This can be particularly beneficial for establishing new pastures or in areas with poor soil structure. The soil type at the site was a shallow sand over a dense gravel subsoil which had very few rocks present, and this meant that the soil strength was very high down the soil profile (Figure 1). The control treatments highlight that root growth would start to become limited at 175mm soil depth where soil strength exceeds 2500kPa (red dashed line). The amelioration treatments have effectively increased the unrestricted root growth layer to 250-400mm depth.
Figure 1. Soil Strength under all treatments 6 weeks post amelioration. Note: There are two control plots at this site.Figure 2. Biomass at growth stage 30 (GS30) for all treatments. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
All ameliorated plots tended to have a higher biomass than the control plots, with the highlight being an increase of 58% for the Nufab (single pass). In comparison, the common method of ameliorating this type of soil (Plozza plow) was only 26% higher. This difference between Nufab (single pass) is likely due to the increased depth of loosening of topsoil compared to all other amelioration treatments.
Figure 3. Biomass at flowering stage of the crop for all treatments. Error bars denote the standard error of the treatment mean. Lower case letters denote significant differences (P<0.05) within treatment groups, ns = no-significant difference.
At the flowering stage of the crop, the Fanger and Nufab (double pass) double treatments had caught up to the Nufab (single pass) treatment compared to the GS30 stage and were significantly higher than the control treatments. When compared to the control, the Fanger and Nufab (single pass) treatment increased plant biomass production by a whopping 75% and 68% respectively.
The results confirm that amelioration treatments can significantly reduce soil strength, allowing increased plant biomass production. This is particularly important on this soil type which contained a dense gravel layer impenetrable with a shovel beyond 10-15cm limiting plant growth. The Nufab (single pass) was the most effective treatment to improve biomass production and this is likely due to the mechanical action the machine has in the soil. The Nufab ripper had delving plates on the ripping tines which mixed the soil and likely led to the large reduction in soil strength down to 400mm. However, the ripping tines extended down to 550mm soil depth, providing loose soil in pockets where the ripping tines had traversed (Figure 4). In comparison, the Plozza plow was effective at reducing soil strength in the top 30cm, but owing to the mechanical disc action in the soil, did not have any effect on the subsoil. Interestingly, a double pass of the Nufab ripper was not better and it is unknown why this was the case, although this treatment had a significantly higher percentage of gravel present in the topsoil after being ameliorated. It is important to note that this gravel soil largely had an absence of rock in the subsoil and this would affect the performance of the Nufab ripper. Further work is needed to understand the impact of all soil amelioration treatments on the chemical and physical properties of a gravel dominant soil type.
The positive benefit of any type of soil amelioration on crop biomass production can be clearly seen at this site for the 2024 season. The effect can be seen for both early and late season biomass production and this creates many opportunities for adding value in a mixed cropping/grazing system. Early feed can be increased through soil amelioration where the soil is loose immediately following treatment and this can be of benefit in a grain and graze situation where the crop is being grazed by livestock early in the season.
A downside to increased biomass production is the potential for the crop to ‘hay-off’ later in the season where crop growth is far greater than the soil and soil moisture can support, resulting in low grain yield. In-crop grazing to reduce biomass has been shown in the grain-and-graze program to lessen the impact of this and could be an effective strategy where biomass production is greatly increased from soil amelioration. However, in the case of hay production or cereals sown as a pasture species where crops ‘haying-off’ is not an issue, greater biomass production has little downside risk. Improved pasture production in the first year following soil amelioration can greatly assist in covering the cost of the amelioration if this biomass production can be efficiently converted into salable product (i.e. meat, wool). Future work on the economics of hay and cereals-as-pasture to pay back the cost of amelioration similar to the yield uplift in cropping systems may uncover alternate methods to pay for most of the cost of amelioration in the first year.
An additional side benefit of increasing pasture production is an increase in soil ground cover to protect the soil and increase soil health, which has been highlighted as an issue in our region over the past few years. Care should be taken when grazing following amelioration to ensure that 50% groundcover is maintained during the season as this can negate the risk of wind erosion in the region.
These findings align with broader agricultural principles, where improved soil conditions typically lead to higher crop growth, better yield potential, and the possibility of using crops for additional purposes such as grazing or pasture species. Further monitoring and research will help to refine these findings and confirm the long-term benefits of these practices for managing water repellence and improving soil fertility.
If you’d like to learn more about the overall purpose and aim of the Soil Water Repellence Project click here.
If you’re looking for an in-depth look at each of the amelioration methods used and what was discussed at the first site crop walk click here.
If you’re interested in getting more information on soils, workshops and related events click here.
One of the main side effects of high crop production and grain yields is an increase in crop stubble left behind after harvest. Despite the long-term benefits of stubble retention, such as improved soil health and water retention, increased organic matter, and prevention of erosion, farmers often struggle to consistently adopt this practice due to short-term management issues. Machinery blockages, reduced crop establishment, nitrogen tie-up and issues with herbicide efficacy and pest control are some of the main challenges. The West Midlands Group (WMG) and Corrigin Farm Improvement Group (CFIG) are helping address these challenges by evaluating different stubble management strategies at 6 sites across the Wheatbelt.
Another key focus of this project is to ensure that farmers achieve adequate groundcover—ideally above the 50% threshold—to significantly reduce the risk of wind and water erosion. Several stubble management strategies were implemented after two successive high production years (2021 & 2022) to allow farmers to keep as much stubble as possible and included leaving stubble standing (existing practice), using machinery to manipulate stubble, and applying nitrogen or bio-stimulants pre-seeding to stimulate stubble breakdown.
Machinery manipulated stubble treatment (left) next to standing stubbles (right) in Yathroo.
To monitor soil groundcover at each of our 6 sites, satellite imagery has been used to estimate fractional groundcover for each treatment, with in-paddock ground truthing in Autumn and Spring of each year. Figure 1 shows that across all 6 sites in the Wheatbelt, soil groundcover was lowest in March and highest in September. This follows the common pattern of groundcover being lowest in Autumn prior to seeding, and highest in Spring preceding harvest.
Figure 1. Combined soil groundcover percentage across all sites and treatments in 2024.
When analysing the satellite data, all sites are presenting consistent results across treatments with the majority staying above the recommended 50% groundcover threshold (Figure 2). There was an expectation that machinery manipulation and biostimulant treatments would have a greater impact on soil ground cover as they are both working to reduce the amount of stubble on the soil surface. Machinery manipulation incorporates stubbles into the soil for ease of seeding, while adding a biostimulant was hypothesised to increase microbial activity and stubble break down. These effects however, were only transient and groundcover increased following the break of each season.
Figure 2. Soil groundcover highlighted across all sites for the 2020-2024 seasons. The red dotted line indicates recommended ground cover threshold (above 50%) and the solid black line indicates input of stubble management treatments.
As shown by the spikes in groundcover percentages, lowest groundcover levels come at the beginning of each season between harvest and seeding. However, a lessening in the severity of these periods of low groundcover can be seen over time following the input of stubble management treatments across all sites, indicating an overall increase in consistent groundcover (Figure 2).
High groundcover levels at the end of each season is also consistent with annual rainfall data (Table 1). 2023 was a lower rainfall year than 2020 (Table 1), however when comparing these two years in groundcover percentages, 2023 was higher (Figure 2). This is an indication that over time, stubble management treatments have increased consistent groundcover across all sites.
Site
2020
2021
2022
2023
2024 (to date)
LTA (long term average)
1
405.5
703.2
660.1
327.2
477
513.9
2
492.6
715.8
649.6
377.6
473.6
568.3
3
492.6
715.8
649.6
377.6
473.6
568.3
4
276.4
429.4
361
325.4
347.2
377.4
5
259.4
457.3
444.6
329.4
225.1
372.5
6
243.2
348.6
430.3
182.8
254.3
320.8
Table 1. Total rainfall (mm) across Stubble Management Project sites 2020 to 2024.
As the Stubble Management Project nears completion, the demonstration trials have shown that effective stubble management strategies can enhance groundcover consistency and reduce erosion risks, even during dry years. Despite rainfall variability, the data collected across this project indicates that these practices can help farmers maintain groundcover above the critical 50% threshold, which is vital for long-term soil fertility and sustainability.
This Stubble Management Project is supported by funding from the Western Australian Government through the State NRM program. For more information, head to the project page or get in contact with WMG Project Officer Kate Parker at projects@wmgroup.org.au.
One of our main trial sites in 2024 has been on Tim Creagh’s gravel soil paddock in Dandaragan. Tim and WMG have been looking into how different soil amelioration methods perform on his gravel soils, which are increasingly becoming more water repellent. Four different soil amelioration methods, including inversion tillage with a Plozza Plow, deep ripping with delving plates (Nufab deep ripper – both single and double pass), and mixing and delving with the Plozza ‘Fanger’ have been tested across the site. While the primary focus of this GRDC funded project is to address soil water repellence, an additional benefit of soil amelioration can be the reduction of weed populations. Controlling weeds on gravel soils is notoriously difficult and although there has been research into the effects of soil amelioration on weed populations in sandy soils, data on gravel soils is limited.
Figure 1. Visual difference in weed populations in Fanger plot vs Control plot.
The site had a high background weed population, mainly capeweed, with some ryegrass, subclover, and radish due to its long history as a permanent pasture. Visual observations of the trial site (Figure 1) indicate that the presence of weeds was having a significant effect on crop growth, and this is expected to impact on final grain yield. All four amelioration methods were highly effective in reducing weed populations immediately following amelioration, with significantly higher number of weeds present in the control plots compared to all ameliorated plots (Figure 2).
Figure 2. Presence of weeds in each treatment, with 0% indicating no weeds present and 100% indicating severe infestation of weeds.
The efficacy of amelioration treatments on weed population is likely due to amelioration generally burying weed seeds well below the surface where they are not able to effectively germinate and emerge from the soil. Alternatively, lower and slower germination may also be an impact on weed growth as by the time any weeds get out of the ground, the crop has already got away and can directly compete with the weeds. Interestingly, the Fanger and Nufab machines were as effective in reducing weeds through deep mixing of the soil compared to Plozza plowing which inverts the soil and buries the weeds at the bottom of plowing depth.
Weed control with soil amelioration can be applicable to a wide range of situations. At this site we have seen the positive effect of soil amelioration on crop production, however this can also be an effective method of weed control prior to sowing pastures, or in farming systems that seek to reduce herbicide use. An important risk to consider when ameliorating is that burying weed seeds can result in inconsistent control with pre-emergent herbicides, as weeds may germinate from below the treated layer, as well as weeds not being effectively buried by a poor amelioration technique. At this site, we had professional guidance to ensure best practice soil amelioration, and this is reflected in the results.
The results from the first year have demonstrated that soil amelioration methods can have significant added benefits such as reducing weed populations. The effectiveness of these methods, particularly in burying weed seeds and reducing their emergence, highlights the potential for integrating soil amelioration into broader weed management strategies. This project will continue across 2025 and 2026 as well as expanding to new gravel and sand soil type sites across the Northern Ag region. As we explore new methods for addressing soil water repellence we will also expand on our knowledge of the additional benefits and potential challenges to soil amelioration practices, such as the effect on weed populations.
If you’d like to learn more about the overall purpose and aim of the Soil Water Repellence Project click here.
If you’re looking for an in-depth look at each of the amelioration methods used and what was discussed at the first site crop walk click here.
If you’re interested in getting more information on soils, workshops and related events click here.
Looking back to the early 2000s, life seemed much simpler. We hadn’t yet faced a global pandemic, several financial crises, or the aftermath of the 9/11 attacks. The role of data and information in our world was evolving, becoming more accessible. It’s anticipated that the pace of change in this century will far outpace anything we’ve experienced throughout human history, and it’s only going to accelerate. Amidst this backdrop, my journey back to the family farm in 2002 was a significant personal milestone.
My first year back was a steep learning curve after finishing my studies. We had just expanded the farm, so things were incredibly busy. By the end of the year, I finally sat down and took a breath. My mother looked at me and said, “It’s not what you thought it would be, is it?” I laughed it off, but she was right—it was pure madness. We had so much going on post-expansion that things just weren’t nailed down.
Our bank manager loved his annual visits to our farm. He remarked that he didn’t get out of the office much, but always made sure to spend a full day with us. He was amazed that every paddock was a trial site—we were always experimenting. With so much happening, we needed to get organised.
One of the first things we did was to sit down and map out our business goals and what we wanted to achieve. This involved paper and coloured pencils, but that’s a story for another time. We knew we wanted to be in the top 5% of farms in Victoria. To achieve that, we had to be razor-sharp and implement best practices in every management decision and action on the farm.
Enter the Critical Control Point (CCP) planner, based on the HACCP system from the food industry, which ensures quality and safety. The CCP planner helped us manage everything that needed to be done on the farm to ensure success each year. Just like serving food in a restaurant, we wanted to make sure our “meal” (profit) arrived safely without any “casualties” along the way.
The planner had 12 pages and laid out like a calendar with 4 weeks (roughly) to a month. Each week was divided into three sections. The first section listed priority tasks that had to be completed first in that week, specifying the date if it was that critical. Putting the rams out on the 15th February went here. The second section contained important but less critical tasks like preparing paddocks for seeding – this could be done this week or next. The The third section included tasks that could be done when we had spare time—a rare luxury. Tasks like fixing fences and cleaning water troughs fell into this category.
We also reorganised our production system. At that time, we had three shearing periods, three lambing periods, and crops to plant for both winter and summer. Applying best management practices, we consolidated to one lambing period, which simplified our business significantly. This meant the rams went out and came in within a specific timeframe, allowing us to focus on what was important at the right time. For example, the second week of April was always for pregnancy testing, followed by seeding over the following 4 weeks.
This approach ensured we were always focused on the critical tasks at the right time to set us on the pathway for a successful year.
The development of the CCP planner brought clarity and focus to our work. It transformed our approach, ensuring everyone knew (and agreed) exactly what was important and when it needed to be done to achieve our goals for the year.
One of the most ingenious aspects of the planner wasn’t just its development or the thought process behind it. Once completed, it was turned into a calendar using a simple display book and hung on the back of the dunny door in everyone’s house. Each morning, as we contemplated the day ahead, we could also see what was important for the farm business that week!
I encourage you to consider your business and whether you can similarly map out what’s important and when tasks need to be completed. Have you ever thought about how a detailed plan could transform your operations? Through having a plan, we found that much of the noise and uncertainty in farming dissipated and we could identify what wasn’t working and change it for the better. More importantly, we gained time back in the week to do what we loved to do – enjoy the process of farming!
