Background

Landscapes of the Burnett Mary encompass a complex distribution of soils.  This is the result of a long history of interactions between climate, geology, topography and the biological cycling of material between plants, animals and micro-organisms.  Apart from narrow strips of young alluvium deposited by rivers and streams, and coastal sand-mass deposits, the majority of the region has comparatively old undulating to hilly landscapes.

Effective land management practices and adoption of industry Best Management Practices (BMPs) are central to the future health of soils and land condition.  Both rely on a clear understanding of landscape and soil processes.  In turn, healthy soils and landscapes will maintain soil/land productivity and avoid degradation.  Reducing fragmentation of agricultural land and avoiding land use conflict is critical to maintaining the long-term economic viability of productive soils.

Ultimately, improving land condition through effective planning and innovative/adaptive management, particularly with respect to climate variability, will enable:

  • continuing agricultural production
  • biodiversity conservation
  • functioning of ecosystem services
  • supported urban development
  • sustainable, mineral and gas resource extraction
  • improved surface, ground and marine water quality.

Asset Description

For the purposes of the NRM Plan, soil types have been grouped on the basis of inherent similarities in chemical / physical properties and aspects of management, into Soil Management Units.  The Burnett Mary’s soil management units are:
Asset Code Asset Description
SR 1 Dermosols (sandy surface) includes non-sodic Chromosols/Kurosols/Kandosols
SR 2 Dermosols (sealing loamy surface) includes non-sodic Chromosols/Kurosols/Kandosols
SR 3 Dermosols (structured clay/clay loam surface)
SR 4 Ferrosols
SR 5 Hydrosols (sandy surfaced)
SR 6 Hydrosols (sealing loamy surfaced)
SR 7 Hydrosols (structured clay/clay loam surface) including Organosols
SR 8 Rudosols/Tenosols (loamy)
SR 9 Sodosols (loamy surface) including sodic Chromosols/Kurosols
SR 10 Sodosols (mod deep (>0.5m) sandy surface) including sodic Chromosols/Kurosols
SR 11 Sodosols (shallow (<=0.5m) sandy surface) including sodic Chromosols/Kurosols
SR 12 Tenosols/Rudosols/Podosols (sandy)
SR 13 Vertosols
More detailed description of these units, their distribution and predominant land uses is available in the Background report – Land and Soils.

Potential Climate Futures

The Land and Soil expert panel considered the vulnerability of soil management units to climate change exposure indicators.  Temperature increases, increasing lengths of dry periods, decrease in Spring rainfall, more frequent and intense fires and more frequent intense rainfall events were identified as the indicators likely to impact the region’s soil resources.

In projecting the impacts the panel did not distinguish between future climate scenarios RCP4.5 and RCP8.5 for 2030 but suggested that there was too much conjecture regarding 2090 conditions under RCP8.5 to confidently project that future for the region’s soil resource.

Climate Scenario Potential Climate Future 2030 Potential Climate Future 2090
RCP4.5 Some increase in soil temperature reflecting atmospheric temperatures but productivity largely unaffected; Vertosols have significant linear increase due to inherent dark soil colours. Significant increase in soil temperature and reducing productivity.
All soils with some to significant increase in drought periods affecting soil surface cover and productivity, soil organic matter and landscape hydrology; particularly shallow soils, sandy surfaced soils and Hydrosols. All soils with significant to major increase in drought periods particularly soils with shallow rooting depths and Hydrosols, while Dermosols, Ferrosols and Vertosols least affected.
Some decrease in soil moisture reflecting spring rainfall decrease and reduced surface cover; Sodosols more affected. Significant to major decrease in soil moisture reflecting spring rainfall decrease; Sodosols more severely affected.
Minor to some effects on the soil organic matter content, surface cover and erodibility due to more frequent and intensive fires, with moderate effects on Sodosols and high effect on structured Hydrosols due to lower water table and loss of organic matter. Some effects on the soil organic matter content, surface cover and erodibility of the more productive soils due to more frequent and intensive fires, with very high effects on Sodosols and extreme effects on structured Hydrosols due to lower water table and loss of organic matter.
Some increase in soil erosion in all soils due to more intensive rainfall events, with a high increase on erodible Sodosols due to reduced ground surface cover, loss of  soil organic matter, increasing run-off and decreasing structural stability. Some to moderate increase in soil erosion in all soils due to more intensive rainfall events and reduced ground surface cover and loss of soil organic matter, with extreme increase on erodible Sodosols due to increasing run-off and decreasing structural stability.
Additional information regarding these potential climate futures for the region’s land and soil assets is Background report – Land and Soils.

Strategic Direction

Land condition and soil health within the region will be maintained or improved.

2020 Target (Salinity)

LS1. Salinity extent and severity is maintained at 2015 baselines. MODERATE

Desired Outcome

Mobilisation of salts in the landscape results in no further loss of agricultural productivity or negative impacts from saline runoff into adjacent vegetated communities and waterways.

2020 Target (Acidification)

LS2. Soil acidification is maintained at the 2012 baseline for agricultural land. LOW

Desired Outcome

Soil pH in agricultural land is managed to maintain or reduce negative productivity and soil health impacts.

2020 Target (Soil organic matter)

LS3. Soil Organic Matter is maintained at the 2012 baseline for agricultural land. MODERATE

Desired Outcome

The biological, chemical and physical properties of agricultural soils are not compromised by loss of soil organic matter.

2020 Target (Erosion)

LS4. Sheet erosion risk, stream bank erosion risk and gully erosion extent and severity do not exceed 2015 baseline levels. HIGH

Desired Outcome

Land productivity is maintained and total soil loss and infrastructure damage is reduced.  Nutrient and sediment loads in streams will be reduced by 20% to support the Reef Plan.

2020 Target (Acid sulfate soils)

LS5. The extent of acidification caused by the disturbance of Acid Sulfate Soil does not exceed the 2015 baseline. LOW

Desired Outcome

Disturbance of Acid Sulfate Soil will be avoided.  In cases of disturbance, the impacts of acid sulfate soil disturbance (acid drainage and pollutants in waterways, and infrastructure damage) will be effectively managed.

2020 Target (Cropping land)

LS6. The extent of suitable Cropping Land (i.e. cropping, horticulture and plantation forestry) is maintained at the 2015 baseline. HIGH

Desired Outcome

The potential for agricultural production on cropped and undeveloped land, suitable for crop production, will be preserved.

2020 Target (Grazing land)

LS7. Ground cover of Grazing Lands is maintained at or above the 2015 baseline. HIGH

Desired Outcome

The productivity and sustainability of Grazing Land will be enhanced through implementation of Best Management Practices and Grazing Land Management.

See Background report – Land and Soils for additional material regarding this asset.