Changing the landscape with soil health

Dr Christine Jones, Elizabeth Lyons, Four Mile, and Peter Le Feuvre, Belmahar, inspecting root systems and soil aggregate. There is a huge appetite for soil, ecology and grazing information in the Dry Tropics region including Bowen and Collinsville areas, landholders want a better understanding of the science behind pasture management.

David Hardwick explains how to determine soil texture using the ribbon test.

Julie and Reid Muirhead, Weetalaba Station.

Graziers walked paddocks with a shovel to dig up clumps of soil to learn more about soil structure. They are adopting grazing management regimes to help restore hydrological balance and build new topsoil.

Graziers in the Bowen, Collinsville Ayr and Eungella regions have delved deeper into soil health with two of the best in the ‘soil health’ business – internationally renowned soil ecologist and founder of Amazing Carbon Dr Christine Jones, and agricultural ecologist David Hardwick, of Soil Land Food.

NQ Dry Tropics’ Landholders Driving Change (LDC) project hosted seven soil masterclasses across the Dry Tropics region.

They aimed to increase landholder understanding of biological mechanisms, especially the role of plant root exudates and their relationship with the microbial communities involved in soil building.

LDC project manager Lisa Hutchinson said this knowledge would help landholders make informed decisions about grazing practices to enhance soil health, increase plant productivity for drought resilience, and improve livestock nutrition and economic bottom lines.

“There is a huge appetite for a combination of soil, ecology and grazing information in the Dry Tropics region,” Mr Hutchinson said.

“Landholders are wanting a better understanding of the science behind pasture management.”

Grazier Reid Muirhead, of Weetalaba Station, Collinsville, said he hosted one of Christine Jone’s masterclasses because he wanted to learn more about how pasture management could affect pasture diversity and productivity, and how they the extent to which they nourished soil organisms.

“It was interesting to learn how these organisms are important to the cycling of nutrients and the maintenance of good soil structure, which in turn can have enormous positive effects on plant growth and animal production,” Mr Muirhead said.

Grazier Wayne Reading, of Borderway Ridge Station, Eungella, said he hosted one of David Hardwick’s masterclasses to gain practical skills to assess the condition of soil on land types across his property using the Rapid Assessment of Soil Health (RASH) approach.

“Learning to assess ground cover, water infiltration and soil texture, aggregate and soil pH, and soil organisms, and how to better understand soil tests results means I can make informed decisions to improve pasture,” Mr Reading said.

Ms Hutchinson said soil health knowledge would move landholders towards restoring hydrological balance on a catchment scale and therefore strengthen rural communities through their impact on farm profitability.

“This approach, including getting the best in the business to come into the region to workshop soil health, aligns with the overarching aims of the Landholders Driving Change project, working with landholders to reduce sediment on the Great Barrier Reef by targeting erosion hotspots and grazing land management practices,” Ms Hutchinson said.

Mick Sheehy (left), and Wayne Reading at David Hardwick’s Crediton workshop.

David Hardwick, Beth Reading, Juliane Kasiske examine the diversity of soil organisms.

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KEQ #1

Figure 1. Total fine sediment reduction by project type and erosion source. Inset shows the proportion of the total project area for each project type.

These estimates have been calculated using two methods: 

1) The pollutant reduction component of the Alluvium/Great Barrier Reef Foundation (GBRF) investment tool for hillslope and streambank erosion management projects; 

2) The Reef Trust Gully Toolbox method for gully erosion management projects. The LDC Water Quality Report 2020 (Waterhouse et al., 2020) highlights that a number of assumptions underlay these calculations, therefore these figures should be treated as the best available estimate of sediment reductions to date.

Preventing sediment from reaching the Great Barrier Reef

Each wet season sediment is washed into local waterways and out to the Great Barrier Reef (GBR). 

Most sediment is very fine, and can stay suspended for a long time and can travel great distances. Valuable topsoil is lost from production, and increased concentrations on the reef can be harmful to seagrasses and corals. 

Landholders in the BBB have completed 69 on-ground water quality practice changes, and it is estimated that these have contributed a fine sediment reduction of 6,154 tonnes per year from reaching the GBR. 

Of this, approximately half of the sediment savings are attributable to grazing land management changes on hillslopes and streambanks, and the other half as a result of gully remediation treatments across a broad range of scales, as shown in the graphs above. 

The table below also highlights the relatively small area of intervention in the gully management projects compared to the large sediment savings that these can achieve - 60 per cent of the sediment savings over only 4 per cent of the project area.

Table 1. Estimated sediment reductions (tonnes) from projects completed in the LDC Project to date.

KEQ #2

*GLMWW = Grazing Land Management Wire and Water

KEQ #3

*The Exploring New Incentives activity area has provided an opportunity for graziers to adopt improved land management practices through a range of activities. For some of these properties, it was the first time they signed contracts for on-ground works.

KEQ #4

The LDC project monitors four gully sites (represented in this table) with gold standard equipment and analysis, carried out by CSIRO.

Results have been compiled in a preliminary report from Bartley et al (2020), with the final report expected to be released by the end of 2020. The preliminary report shows all four sites have indicators of improvements, notably the Strathbogie and Mt Wickham sites.

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Reef regulations - grazing, standard conditions

  1. For land in good or fair condition (more than 50 per cent ground cover at 30 September), continue using measures to maintain land condition.
  2. For land in poor condition (less than 50 per cent ground cover at 30 September), steps must be taken to improve land condition.
  3. For land in degraded condition (less than 20 per cent ground cover at 30 September), steps must be taken to improve land condition OR prevent areas from further degrading or expanding.
  4. Keep records of measures taken and also of agricultural chemicals, fertiliser and mill mud or mill ash applied to land.
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