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Weed control a key focus as new season gets underway

Lucindale, South Australia, grower Lachie Seears is in a development phase of his farm business, having bought a 3200-hectare property in 2021.
Photo: GRDC

Western Australia

Mitch and Emma Miolini farm with Mitch’s brother Adam and sister-in-law India, together with their parents Robert and Maxine. The Miolini family are fourth-generation farmers at Mount Walker in Western Australia, 40 kilometres east of Narembeen in the central wheatbelt. Their enterprise is a mixed farm, cropping wheat, canola, oats, barley and lupins and running 1500 head of breeding ewes. 

Farm size: 5650 hectares, with 75 per cent cropping and the balance pasture. Soil types vary from low pH sands to sand over gravel and salmon gum country.

Average annual rainfall: 340 millimetres, becoming less each year

Professional advice: Planfarm, Wheatbelt Ag Agronomy

Memberships: Corrigin Farm Improvement Group and a local grower-only Soil Constraints Group.

Key changes: A major change to our farm in the past five years has been the adoption of a 12-metre controlled traffic farming system, together with a program of soil amelioration. We aim to ameliorate 500 to 600ha a year. Plozza ploughing has been implemented, together with deep ripping and lime incorporation. Variable-rate technology is also being used for seeding and fertiliser application. I am developing methods to run sheep more efficiently within the cropping enterprise, with fodder feeds (oats, vetch and tillage radish blend) planted early and brown manured later to be able to crop more hectares.   

2024 goals: I aim to continue implementing the soil amelioration improvements over the farm and to consolidate on results they have been achieving. Different practices will be trialled this year, on the first-ameliorated paddocks, to gauge the best results going forward. Ameliorated country has all been Plozza ploughed then deep ripped, so further treatments will assess the use of offset discs, deep ripping, Plozza plough by itself, and Plozza and deep ripped again. Another one to two tonnes per hectare of lime will be incorporated as well.

Challenges and opportunities: With the declining annual rainfall, summer rain and retaining moisture are becoming a big thing. Any available summer rainfall needs to be used to help drive crop yields. Input costs and weed control are becoming more challenging, so utilising available technology is an opportunity to try and negate some challenges. We are using a contractor for green-on-green technology as well as green-on-brown where applicable. We added a variable-rate section control to our seeder last year and will implement more variable-rate maps for fertiliser, seed and flexi nitrogen at seeding time. I am prepared to take on some risk – in terms of weathering frost at the end of the season – to sow legumes and canola early to establish crops on retained summer moisture and give them the best opportunity.

R&D wish list: I am keen to see more in-depth research into quantifying the benefits of different fallows – including legume and chemical fallows – and their place in a mixed farming system. Another item on my wish list is more research and development on soil amelioration and progressing into subsoil amelioration and the placement of lime/gypsum at deeper depths to improve subsoils and make more moisture available for crops.

South Australia

Lachie Seears farms with his wife Rebecca and children Hugh and Anneliese, along with his parents Peter and Helen, at Lucindale in south-eastern South Australia. Their enterprise consists of cropping (wheat, canola and broad beans), 6500 breeding ewes and 1250 breeding cows and heifers (building towards 2000 breeders).

Farm size: About 6000ha across two properties – ‘Boonderoo’ (2800ha) and ‘Elad’ (3200ha). Cropping is approximately 1400ha.

Average annual rainfall: 650mm

Professional advice: Tom McKinnon, Nutrien Agronomist (Lucindale).

Memberships: MacKillop Farm Management Group, Nuffield Australia, Grain Growers, Livestock South Australia.

Key changes: We doubled the size of our business in May 2021, purchasing ‘Elad’ – a 3200ha blue gum plantation where we have stump ground out more than 3,000,000 stumps to revert it back into a cattle grazing property. This has allowed for an increase in cropping area at ‘Boonderoo’. Recently I have moved to simplify the farming operation and went through the process of identifying what we were good and what was profitable and cut some enterprises from our workload.

2024 goals: As we are still in a developing phase, we are investing heavily in the cattle property and want to maximise profitability across the sheep and cropping enterprises as we build cattle numbers. Timing, timing, timing! Every operation we undertake has an optimal window to be performed; this is the key to success when cropping in the high-rainfall zone. We need to ensure we have product ready and available to ensure we have the ability to grow our potential crop yields. As we have been hitting a nine to 10t/ha wheat crop average to miss one of them – for example not getting a fungicide application done when required – can have huge impacts in achieving yield potential. I would like to achieve the following crop averages in 2024: 10-plus tonnes/ha in wheat, 4t/ha in canola and 4t/ha in broad beans.

Challenges: I like to concentrate on what I can control and one of the challenges for 2024 will be having inputs available and on-farm ready for use. Being such a diverse business it’s a challenge to ensure all enterprises and operations are managed correctly. Waterlogging is a huge challenge for us, so it’s very important that our drainage system is maintained to alleviate any damage caused by waterlogging. We see large fluctuations in input costs and, because we run a high-input system, we want to ensure we can get product as cheaply as possible to maximise profitability. Marketing is a huge challenge due to such big shifts in the market in relatively short timeframes.

Opportunities: Farming in the high-rainfall zone presents us with great opportunities to maximise our growing potential. With a relatively reliable growing season rainfall, we have a level of confidence to push inputs such as fertiliser to try to achieve our yield potential. Because we grow feed grade wheats, we have a great opportunity to be able to store and market product all year round, hopefully capturing some price rise opportunities as they present.

R&D wish list: Over the past 10 years, we have seen wheat yields in the high-rainfall zone double from 5t/ha to 10t/ha. This has been largely due to better feed varieties coming into the country and seeing research done by Field Applied Research (FAR) with hyper-yielding trial sites in our area. There is still a lot of work to be done.


Based at Capella, north of Emerald in Central Queensland, Tim Gersbach farms 4000ha with his wife Courtney, their two young children, and his parents Garry and Cathy. They crop wheat, chickpeas and, occasionally, mungbeans. Sorghum is the dominant summer crop.

Farm size: 4000ha

Average annual rainfall: 650mm

Professional advice: Agronomist Josh Bell, JB Ag Services

Memberships: AgForce and GrainGrowers

Key changes (in recent past): One of our very recent changes is to nutrient management. We have traditionally put urea down at planting. But we are going to put it down a few weeks or months earlier with the aim of fertilising the system, not the crop.

It follows on from the work of Emerald-based researcher Doug Sands, from the Department of Agriculture and Fisheries. He spoke at the GRDC Updates in November and, with advice from our agronomist Josh Bell, we decided to try this approach. We raced out and bought a 9000L spreader late last year and have been busy getting out early with the urea.

As part of this new plan, and to help planting when there are high stubble loads, we will also use our vertical tiller. The American tiller, called a Great Plains Turbo Max, is a zero-till implement. We bought it to chop up high stubble loads and allow for easier planting, without disturbing the soil. The plan is to run it behind the spreader and help incorporate the urea.

Challenges and opportunities: Weed control is our biggest challenge. Stopping weed seed set and keeping the paddocks clean is an ongoing job. We have recently started using Glufosinate in our optical sprayer. Glufosinate works well in high humidity – a bonus with the very humid conditions here over the summer. We’ve found it can kill feathertop Rhodes grass in one pass. This chemical used to cost about $30 a litre but has come down to $5.50 a litre.

It also helps us preserve glyphosate. We were looking for a knockdown chemical to help glyphosate – not to replace it – and this works well. It means we can address hard-to-kill summer grasses. We used to aim for a double knock, but that is weather-dependent. We need 10 days of dry weather between the first knock and the second knock and with summer storms that can be difficult. Using Glufosinate in the optical sprayer saves time and fuel.

2024 goals: To keep working on our nutrient management plans and see how fertilising the system works for us.

R&D wishlist: I’d really like to know more about nutrient management. How long can urea sit there before it is lost to the atmosphere? We always apply with the plan for the rain but what happens if that doesn’t happen? Does it all go into the atmosphere?


Mitch Henderson, with parents Craig and Pauline, brother Ben, cousin John, and their families grow wheat, barley, lentils and oaten hay in Berriwillock, Wilkur and Brim in Victoria’s Mallee. They also rear poultry, using their wheat straw as bedding and then spreading it back on to paddocks as manure in a closed-loop system.

Average annual rainfall: 350mm

Professional advice: Agronomist Craig Landwehr at Agrivision consultants

Memberships: Birchip Cropping Group, Victorian Farmers’ Federation (where Craig Henderson is president of the Grains Council)

Key changes: We got rid of sheep altogether, which changed our practices to focus on crops. A parallelogram seeder has greatly helped our crop germination and early vigour.

We have put seed mills on headers to harvest weed seed and are now camera spraying. We have done some green-on-brown and are dabbling in green-on-green (targeting weeds in-crop). The first changes brought significant gains and the camera spraying I think will help us even more controlling weeds.

2024 goals: We are looking forward to maximising our potential – nailing down the little one-percenters to get there. We want to trial more of the green-on-green (spraying) – that excites me a bit.

We also want to try to improve our timing, mostly around sowing and spraying. Our windows for spraying aren’t very big so we’d like to get that program tightened up a bit. And we’re also trialling some different varieties next to each other. It’s all part of the learning process.

Challenges and opportunities: Our production can be quite variable and that’s predominantly down to rainfall, but we also run the risk of frost. Lentils have the potential to make the most money, but if the year dries off there’s a higher risk of frost that reduces yield and quality – so it’s a challenge. But in saying that we have a reasonable (moisture) profile this year, so it’s very promising.

Inputs are a big challenge – we bought starter fertiliser in September because we thought it would get tight. We are at the mercy of suppliers – securing glyphosate and parts for machinery have been an issue since COVID-19. It’s the new norm that if you want it you need to carry it.

R&D wishlist: I’d love more non-chemical modes of action to control weeds. I believe that it will be a necessity in the future – whether it be from (herbicide) resistance or that as producers we are benchmarked or audited based on our chemical inputs in global markets. It might be five or 10 years down the track but it’s coming.

The other one I really wouldn’t mind is accurate weather forecasting but wouldn’t everyone?

With 3G turning off I’d like to see some technology around the phone service. A lot of our machinery is now connected through the mobile network – and the insights and real-time feedback we get is great but, if we have no service, we can’t access any of it.

I’d also love an app where we can run an inventory system of not just our grains, but fertiliser, fuels and everything else. There are apps that do different bits and pieces but for management it would be nice to join the dots and have it all on one database so you could make real-world decisions on the fly.

New South Wales

Andrew Freeth, his parents David and Sue, and his brother Marc grow wheat, canola, chickpeas, faba beans, oats and 2200 ewes and trade cattle near Collie and Trangie in central New South Wales.

Average annual rainfall: 500mm, slightly summer dominant

Farm size: Almost 5500ha, with 2200ha cropped

Professional advice: Agripath benchmarking group, accountant and other specialists as needed

Memberships: Grain Orana Alliance

Key changes: In the past few years, we’ve sown wheat and canola across more hectares at the expense of pulse crops to take advantage of wetter seasonal conditions and higher prices for canola. Accordingly, we’ve sown lucerne to add more nitrogen to our soils.

2024 goals: We aim to do everything on time. We will sow Illabo (PBR) grazing wheat for the first time, giving the ewes some feed before locking up the paddocks for grain production. The stripe rust tolerance of Illabo (PBR) makes it more attractive than other long-season wheat varieties.

We aim to execute our management as best we can for the most-profitable outcome. We will plant more of our country to chickpeas this year at the expense of canola and, to some degree, wheat.

2024 challenges: One challenge is whether there will be a sufficient seasonal break. At Collie, by the end of January, our soil profile was half to three-quarters full of water. Our block at Trangie had less water available. This means we need plenty of rainfall between 1 February and 1 April to plant canola.

Another challenge is that we are coming off a high-price environment following the Russia-Ukraine war and a drought in Canada. These factors inflated wheat, barley, feed grain and canola prices. This also led to high input prices for glyphosate, mono-ammonium phosphate and urea. Trying to manage our margins if the price of inputs doesn’t fall as quickly as commodity prices is front-of-mind. We are also mindful of potential supply chain disruptions and aim to be more proactive in ordering inputs well ahead of when they will be needed.

R&D wishlist:

  • Continued investment in delivering research outcomes that will profit growers.
  • ‘Blue sky’ research investment is critical. This might not be commercial, but it is essential that GRDC provides seed funding so innovative commercial products will become available to growers.
  • Continued investment in existing grower groups to help extend research outcomes to growers and agronomists.
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