
State and trends of soil carbon
State and trends of soil carbon
Rangelands with extensive grazing and wind-borne soil erosion, particularly on sandplains. In western New South Wales, 74% of soil monitoring units report SOC reduction as an issue
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Rangelands with extensive grazing and soil erosion caused by wind particularly on sandplains
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Rangelands with minor opportunity cropping. In western NSW, 74% of soil monitoring units report SOC reduction as an issue
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Rangelands with minor opportunity cropping
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Grazing of modified and natural pastures, and nature conservation are major land uses. In the Central Plateau of NSW, 33% of soil monitoring units report SOC reduction as an issue
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Land used for grazing of modified and natural pastures and nature conservation. Significant losses of soil carbon, particularly in the east
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Infertile coastal lowlands used for forestry, grazing, cropping and some nature conservation. In the North Coast region of New South Wales, 56% of soil monitoring units report SOC reduction as an issue
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Infertile coastal lowlands used for forestry, grazing, cropping and some nature conservation
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Historically poor management has depleted SOC. Overgrazing by feral goats is causing further decline, despite improving land management. In western New South Wales, 74% of soil monitoring units report SOC reduction as an issue
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Significant declines in soil carbon, mostly associated with historically poor management. Overgrazing by feral goats is causing further decline, despite improving land management
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Surface SOC is low as a result of grazing and prior clearing. In the Central Tablelands region of New South Wales, 40% of soil monitoring units report SOC reduction as an issue
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Surface content of carbon declining due to grazing and prior clearing
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Declining trend due to intensification of cropping. In the north-west region of New South Wales, 18% of soil monitoring units report SOC reduction as an issue
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Declining trend due to intensification of cropping
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Area used for nature conservation and production forestry, with some grazing. Possible decline in SOC due to logging. In the Hunter region of New South Wales, 50% of soil monitoring units report SOC reduction as an issue
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Area used for nature conservation and production forestry, with some grazing. Possible decline due to logging
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Mixed farming on naturally fertile Ferrosols and Vertosols. In the Hunter region of New South Wales, 50% of soil monitoring units report SOC reduction as an issue
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Mixed farming on fertile Ferrosols and Vertosols
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Soils are Sodosols and Vertosols, used for cropping and grazing. in the Central West region of New South Wales, 19% of soil monitoring units report SOC reduction as an issue
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Sodosols and Vertosols used for cropping and grazing
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Grazing of modified and natural pastures dominates. In the Central Tablelands region of New South Wales, 40% of soil monitoring units report SOC reduction as an issue
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Grazing of modified and natural pastures dominates. General improvement in land management practices
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Diverse landscape with natural conservation, forestry, grazing, horticulture and urban land uses. Fire regime and land management practices are most likely causing a decline in SOC. In the Greater Sydney region of New South Wales, 57% of soil monitoring units report SOC reduction as an issue
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Diverse landscape with natural conservation, forestry, grazing, horticulture and urban land uses. Fire regime and land management practices are most likely causing a decline
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Mostly urban and industrial land use. In the Greater Sydney region of New South Wales, 57% of soil monitoring units report SOC reduction as an issue
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Mostly urban and industrial land use
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In the South East region of New South Wales, 59% of soil monitoring units report SOC reduction as an issue. No data from the Australian Capital Territory
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Relatively infertile lands used for grazing. Suspected slight decline
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Good levels of SOC under nature conservation, forestry, and grazing. Land management is improving
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Forestry, nature conservation and grazing. Land management is improving
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Mostly used for nature conservation. Controls on grazing and reduced erosion stabilised early losses, but the increased intensity and extent of fires are likely to be causing a decrease, particularly in Organosols
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Mostly used for nature conservation. Controls on grazing and reduced erosion stabilised early losses, but the increased intensity and extent of fires are likely to be causing a slight decrease, particularly in Organosols
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Cropping, grazing and nature conservation with irrigated agriculture along the Murray River. Improved farming practices have improved soil condition in some areas
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Cropping, grazing and nature conservation with irrigated agriculture along the Murray River. Improved farming practices have improved soil condition in some areas, but soil carbon levels are probably still declining
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Mainly cropping and grazing. Former grazing lands now used for nature conservation may still be experiencing declining carbon content. Changing farming practices to no-till may be increasing SOC content in some areas, especially on heavier soils
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Mainly cropping and grazing. Former grazing lands now used for nature conservation may still be experiencing declining carbon content. Changing farming practices to no-till may reduce soil carbon loss in some areas, especially on heavier soils. Soil carbon is still likely to be declining in this region
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Dryland cropping and irrigated agriculture, with grazing in the west. None of the soil monitoring units in the Riverina region of New South Wales reported SOC as an issue
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Dryland cropping, irrigated agriculture and grazing, with the latter dominant in the west. Slight declines under dryland cropping systems, although farming practices may halt this
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Grazing, cropping and expanding plantation forestry. Areas converted from pasture to cropland are probably declining, as are soils used for continuous cropping
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Grazing, cropping and expanding plantation forestry. Areas converted from pasture to cropland are probably declining, as are soils used for continuous cropping
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Dryland cropping, grazing and increasing irrigated cropping. Intensification of cropping is probably causing a decline in SOC
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Dryland cropping, grazing and increasing irrigated cropping. Intensification of cropping is causing the decline
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Nature conservation reserves. Where wildfire and grazing have resulted in sheet erosion over large areas, SOC has been lost, with limited potential for recovery
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Nature conservation reserves where wildfire and grazing have initiated sheet erosion over large areas, with very limited potential for recovery
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More frequent and/or hotter fires in conservation reserves are causing losses, especially in Organosols. Production forestry in the north suggests little potential for increase in SOC sequestration
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More frequent and/or hotter fires in conservation reserves are causing losses, especially in Organosols. Northern areas dominated by production forestry, with no potential for soil carbon sequestration
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Production and plantation forestry, with minor decline due to erosion. Irrigated cropping in the south-east and north-east is causing a decline in SOC
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Production and plantation forestry, with minor declines due to erosion. Irrigated cropping in the south-east and north-east is causing declines
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Decline in SOC is associated with irrigated cropping
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Decline is associated with irrigated cropping
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Mainly grazing of native vegetation. Shift from perennials to annuals and possible increase in fire frequency may lead to decline in SOC
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Mainly grazing of native vegetation. Shift from perennials to annuals and possible increase in fire frequency may lead to nominal decline
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SOC decline is restricted to pastoral areas
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Soil carbon decline restricted to pastoral areas
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Urban areas and intensive agriculture. High levels of SOC are often associated with irrigated pasture. Decline in SOC is likely under intensive horticultural systems
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Urban areas and intensive agriculture. Declines due to tillage. Irrigated pasture systems for dairy may be stable or increasing
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Low input cropping and grazing. Drying trends have compounded effects of clearing and cropping on SOC loss
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Low input cropping and grazing. Drying trends have compounded effects of clearing and cropping on soil carbon
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Areas with extensive grazing of native vegetation, with declines in SOC in more heavily grazed areas. Few data in driest areas
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Areas with extensive grazing of native vegetation, with declines in more heavily grazed areas. Drying trends are an additional factor
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Nature conservation, extensive grazing; small areas of intensive irrigated horticulture likely to have a decline in SOC
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Nature conservation, extensive grazing and small areas of intensive irrigated horticulture. Episodic removal of surface soil carbon in horticultural areas
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Extensive grazing of native vegetation
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Extensive grazing of native vegetation
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Small areas of intensive agriculture are likely to have declining SOC. Remainder is used for extensive grazing
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Small areas of intensive agriculture likely to have declining carbon. Remainder is used for extensive grazing
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Extensive grazing, with small areas of more intensive development on better soils. Possible minor decreases in SOC due to high seasonal stocking rates
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Extensive grazing with small areas of more intensive development on better soils. Possible minor decreases in soil carbon due to high seasonal stocking rates
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Extensive grazing on clay plains, with decline in SOC likely
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Extensive grazing on clay plains. Some impacts on soil carbon due to grazing
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Ferrosols used for cropping and pasture, with increasing agroforestry. Slow recovery after large historical loss of SOC
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Ferrosols used for cropping and pasture, with increasing agroforestry. Slow increases occurring under pasture and agroforestry
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Partially cleared grazing country. SOC is likely to be declining in recently cleared areas; otherwise stable
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Partially cleared grazing country. Soil carbon is likely to be declining where cleared recently, otherwise stable
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Fertile land with high rainfall. Diverse land uses, with SOC now recovering under pastures and tree crops; it is likely still decreasing under small-grain and horticultural crops
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Fertile land with high rainfall. Diverse land uses, with soil carbon now increasing under pastures and tree crops. Stable under rainfed crops but still decreasing under small crops
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Recently intensified land use after clearing; therefore, SOC is likely declining
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Recently intensified land use after clearing. Soil carbon likely to be declining
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Assessment Summary Key
Grades
Very good
Carbon stocks have either remained the same or increased (<30% loss or increase)
Good
Carbon stocks have changed in some areas (30–50% loss)
Poor
Carbon stocks have decreased (50–70% loss)
Very poor
Carbon stocks have decreased substantially (>70% loss)
Recent Trends
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Improving
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Stable
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Deteriorating
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Unclear
Confidence
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Adequate: Adequate high-quality evidence and high level of consensus
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Somewhat adequate: Adequate high-quality evidence or high level of consensus
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Limited: Limited evidence or limited consensus
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Very limited: Limited evidence and limited consensus
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Low: Evidence and consensus too low to make an assessment
Comparability
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Comparable: Grade and trend are comparable to the previous assessment
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Somewhat comparable: Grade and trend are somewhat comparable to the previous assessment
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Not comparable: Grade and trend are not comparable to the previous assessment
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Not previously assessed
Comments
Quality of data used in the assessments is as described by state agencies and/or in journal papers; otherwise assumed to be ‘low’.