Liquid compost sprayer trials have begun on the Atherton Tablelands as landholders explore new ways to improve their soils and reduce chemical inputs.

Farmers are working with Terrain NRM to trial a sprayer designed to support the survival of beneficial bacteria in live liquid compost application. The Cyclone Multi-Task Sprayer arrived from New Zealand last month.

Kairi grazier Kellie Evans, who is also president of the farmer-led Wet Tropics Soilcare group, is one of the landholders trialling the sprayer.

“Nutrition straight to the leaf surface”

“We’ve been making our own compost for four to five years and using a muck spreader to apply it to our pastures before the wet season,’’ she said. “With the new sprayer, we can also have a liquid compost foliar feeder. It gets nutrition straight to the leaf surface and does it efficiently.

“This sprayer is something we’ve been looking at through the Wet Tropics Soilcare group. Through Terrain NRM, it has been brought to the region and we’re hoping for wider usage by landholders once we’ve completed a three-year trial period.”

A sprayer designed for bulk live-liquid products

Terrain NRM’s Maria Ribbeck said the sprayer’s point of difference was its specific design for bulk live-liquid products.

“It can constantly rotate the liquid and keep it aerated. There are no right angles to clog up and the water oxygen levels are at six per cent, which is important for adding aerobic biology,’’ she said.

“Farmers will be trialling two applications a year during growing season and, ideally, we will expand the applications to vermicast, seed distribution, use of bio dynamic preps and mineral balancing.

Reducing chemical inputs while improving soil, water and carbon properties

“The goal is to reduce chemical inputs while improving soil function and structure, water retention and carbon sequestration. It’s also to have an economical alternative for landholders.”

So far, Kellie has sprayed 29 hectares of pasture with liquid compost while Ravenshoe biodynamic graziers Lisa Price and Simon Harden are part way through their first application on 50 hectares.

“We’ve been making thermal compost since 2018 but we hadn’t found an effective way to get it out in volume, and quickly enough across the hectares not to lose oxygen,’’ Lisa said.

Climate Smart funding for Wet Tropics farmers

New farming technology will be put through its paces in the Far North as part of a $1.25 million project, announced this week.

Terrain NRM is working with farmers from across industries and the region to trial machinery and equipment and hold on-farm demonstrations and workshops as part of a larger program focused on helping farmers to adapt to changing conditions.

The Australian Government this week announced a $76 million investment in the Climate Smart Agriculture Program, funding 54 projects across Australia to help primary producers adopt climate-smart sustainable agriculture practices.

Trials in the Wet Tropics

Terrain NRM’s Maria Ribbeck said the projects in the Wet Tropics region included trialing a Cyclone multi-task sprayer for liquid compost application on grazing land, using a Soilkee Renovator to plant mixed species crops in pasture, and bringing an air seeder to the Mossman region for trials of alternative crops and revenue streams.

“The trials will cover 200 hectares of land, collectively, over five properties,’’ Maria said.

“We will be monitoring implementation and establishment costs and weighing this up against impacts on productivity and profitability to give the region’s farmers local case studies for climate-smart farming opportunities, as well as local farms to look at and farmers to hear from.

Workshops on sustainable farming practices

“We will also be holding workshops on sustainable farming practices with farmers across the cane, banana, grazing, dairy and tropical fruit sectors.”

We loved seeing cane growers, banana farmers, graziers, tropical fruit producers and forestry come together for our free soil health workshops led by Simon Mattsson from Soil Land Food.

From examining soil cubes and understanding soil biology to unpacking the carbon and nitrogen cycles – these workshops were all about building the foundations for soil health improvements in the paddock.

Simon is also a farmer and he talked about his own transition from “very conventional sugar cane farming” to regenerative farming with as much focus on what’s happening below the soil’s surface as the crops growing above it. His experiences sparked plenty of discussions.

These workshops, in Tully, Mossman and the Tablelands, followed on from years of ‘Digging Deeper’ soil health sessions. It was great to see new faces and familiar faces. The growing momentum around soil health across the Wet Tropics is both encouraging and exciting.

The workshops were part of Terrain NRM’s Climate Smart Farming in the Wet Tropics project. This project is supported by the Australian Government through funding from the Natural Heritage Trust under the Climate Smart Agriculture program.

A Malanda dairy farmer is trialling new technology to improve pasture and productivity – and the results will be showcased at a demonstration day on Thursday 6 June.

Glen Drury has been working with Terrain NRM to trial the Soilkee Renovator, a minimum till pasture cropping machine that mulches and aerates the soil while planting multiple species into existing pastures. The renovator was designed by Victorian beef producer Niels Olsen, the first Australian farmer to earn carbon credits for his soil under a government-regulated system.

Niels and Glen will be sharing their learnings and land improvements at the demonstration day, on Thursday 6 June, along with Australian Holistic Management Coop CEO Helen Lewis whose organisation, as part of the project, has begun monitoring Glen’s land to measure regenerative outcomes over the next five years.

Glen has planted a mixture of seasonal crops and pasture seeds with the Soilkee Renovator on 150 acres of his 450-acre property.  The aim is to build up pasture biodiversity, soil microbes and carbon.

“We’ve been putting in ryegrass, chicory and clovers for years but the new technology gives us more variety,’’ he said. “We’ve planted legumes, cereal, ryegrass, peas, beans and brassicas. A lot of those seeds are too big to go through the old planter.

“We are looking to grow more feed and more milk.”

He said minimum till was another advantage. “Before, if we worked up a whole paddock, we got really good feed but we had problems when it got wet trying to graze it out. And in the summer when we ploughed and there was heavy rain, it led to erosion.

Four years of ‘citizen science’ mulch trials on lime farms in the Mareeba region has shone a light on what kinds of mulch are the best performers – and it has also led to farming changes.

Mutchilba horticulturalists Michelle and Ante Milicevic are now using Rhodes grass hay annually right across two orchards and, as a result, they’ve improved soil health and significantly reduced their watering and spraying regimes.

“We’d put tea tree and hay in before but not every year,’’ Michelle said. “Since starting annual mulching we’ve been watering a lot less. We used to water every two to three days in the hot dry weather. Now we can push it out to every four or five days, and even a little bit more if we need to.

“Before the trials, we sprayed to keep the weeds down so that our sprinklers worked well. Now we’re not spraying as much because the weeds aren’t coming up. And the ground is a lot easier to dig up. The soil is softer, even where it’s being worked outside the mulch row.”

Four mulches trialled

Terrain NRM and the farmer-led Wet Tropics Soilcare group trialled four mulches – hay, tea tree, pine wood chip and organic matter from mowing the inter-rows – on two farms in the Mareeba district.

Hay was the best performer, followed by tea tree and organic matter. Terrain NRM agronomist Sally Fields said the long-term soil health benefits of woodchip were also evident.

“The trials were on farms with sandy loam soils with a low capacity to hold nutrients (a cation exchange capacity of less than two on both sites at baseline testing in 2021). We took a bunch of measures, full soil tests, leaf sap testing, penetrometer readings and worm counts, and monitored soil health parameters of infiltration. An average yield per tree was also recorded on three occasions at Milinder Farming.

“Growers are recognising more and more the importance of ground cover – keeping your soil covered at all times protects it from water and wind erosion and maximises water infiltration. But many orchards continue to spray under trees and have bare ground under the canopy. We took on this project with Wet Tropics Soilcare because growers were curious to see how much mulch mattered.”

Healthier, more productive trees

Ms Fields said one telling result was the “phenomenal” difference between using side-throw from the mower and mulching – with noticeably healthier and more productive trees under hay and tea tree mulch.

Soil analysis results from both farms showed soil health had also improved under mulch.

She said the trials showed the soil health benefits of woodchip mulch in particular, but also the need to carefully select and apply your woodchip.

“The best choice is ramial (branch) woodchip because the nutrient loads are much higher in the branch-growing region of a tree. Woodchip taken from the trunk will have higher carbon and nitrogen rates and it’ll need more time to break down before using it. Hardwood is better than softwood for orchards. Softwoods like pine need to sit for at least six to 12 months before application to make sure tannins and chemical compounds have leached out.

Terrain NRM will be bringing innovative soil technology to the Wet Tropics region thanks to a new project through funding from the TNQ Drought Hub.

Agronomist Sally Fields said Terrain would create a demonstration site for the Soilkee Renovator on an Atherton Tablelands farm, and would thoroughly assess the seed planter’s potential to improve pasture quality, fertility and resilience in the Wet Tropics.

She said project staff would also work closely with Victorian farmer Niels Olsen, who invented the Soilkee Renovator. The specialist seed planter mulches strips of pasture and can sow a diverse mix of seasonal seeds and seed sizes with minimal paddock disturbance, creating a mass of plant roots for a range of benefits from increasing soil fertility and improving pasture to storing carbon at depth.

“This project is all about activating regenerative soil functions and fertility, increasing the soil’s water-holding capacity and building stable soil carbon in pasture while eliminating the paddock downtime that’s traditionally associated with pasture renovation,’’ Sally said.

“Precision planting of winter annuals into tropical grasses increases diversity and resilience in slow-growing periods. It also allows for slower rotation of cattle and gives graziers more options for stock movements and carrying capacity during the cooler months.

“And it can help to develop healthy soils, improving their capacity to retain moisture and activating the nutrient cycle.”

Forty-one growers from Mareeba to Ingham have trialled changes to their cane-growing practices across 10,000 hectares of land to find the ‘sweet spot’ for productivity and sustainable agriculture.

Changes have ranged from using enhanced efficiency nitrogen fertiliser and applying fertiliser at variable rates to improving soil health through compost production, mill mud application and planting legumes fallow crops. They have also included upgrading soil and yield mapping to better understand each cane block.

The Wet Tropics Reef Trust IV Repeated Tender program is funded by the Australian Government and delivered by Terrain NRM in partnership with Cairns Canegrowers, Herbert Cane Productivity Services and Tully Canegrowers.

Hear from Abergowrie grower Andrew Vella:

Andrew Vella – Abergowrie

Abergowrie cane grower Andrew Vella’s change to enhanced efficiency liquid nitrogen fertiliser has enabled him to average 140kg per hectare on the family’s farms, which collectively have 300 hectares under cane.

Application is down to between 80 and 100kg per hectare on plant blocks – depending on whether he can get a legume crop in or not – so that rates can remain higher on ratoons.

“With the rising cost of fertiliser, you don’t want to waste it. But when you’re cutting back on nitrogen you want to still be able to maximise your production. You want the plant to use the whole lot. It’s a challenge because our growing season varies every year. Sometimes we get a lot of late growth.”

Enhanced efficiency fertilisers

He believes new products, like enhanced efficiency fertiliser, are the key to dropping nitrogen fertiliser rates because “you’re not losing as much nitrogen to volatility or leaching”. But they are currently a more expensive option – and that’s where the Wet Tropics Reef Trust IV Repeated Tender program has helped.

Thirty-eight growers from Mareeba to Ingham have trialled changes to their cane-growing practices across 10,000 hectares of land to find the ‘sweet spot’ for productivity and sustainable agriculture.

Changes have ranged from using enhanced efficiency nitrogen fertiliser and applying fertiliser at variable rates to improving soil health through compost production, mill mud application and planting legumes fallow crops. They have also included upgrading soil and yield mapping to better understand each cane block.

The Wet Tropics Reef Trust IV Repeated Tender program is funded by the Australian Government and delivered by Terrain NRM in partnership with Cairns Canegrowers, Herbert Cane Productivity Services and Tully Canegrowers.

Hear from Ingham grower Paul Marbelli:

Paul Marbelli – Ingham

Third-generation cane farmer Paul Marbelli describes the last three years as a ‘learning curve’. But he says they’ve led to cost-savings and a much better understanding of what his soil needs across 200 hectares of diverse cane blocks.

The Ingham grower reduced his inorganic nitrogen use to an average of 135 kilos per hectare over plant and ratoon cane with the “peace of mind” that the Wet Tropics Reef Trust IV Repeated Tenders program was a financial buffer if he’d dropped too far for his land and the seasons.

“I probably reduced it a little too much,’’ he said. “Now I know how low I can go before starting to lose production when conditions are not as favourable, I’m back around the 140 mark and following soil tests and the Six Easy Steps nutrient management program to the letter.”

The project also helped him to move into variable rate fertiliser application. “Getting a rate control system fitted means we know more accurately how much fertiliser we are placing, so we can be more confident in reducing nitrogen.”

In addition, the Marbellis have focused more on their mill mud application.

“Our farms are close to the mill so we’ve used a lot of mill by-products over the years. But previously we haven’t reduced our fertiliser rates where we’re using mill mud. Now we’ve got more confidence to do that. With fertiliser prices doubling, there is plenty of incentive. There are huge cost savings in finding the balance between minimising impacts on the environment and maintaining a productive farming business.”

The Marbelli family’s farms have creeks crossing through them that flow to the Herbert River. There are wetlands and sediment ponds on most of their properties.