Soil Properties

Climate change is projected to impact on three key soil properties. These properties, soil organic carbon (SOC), sum of bases (macro-nutrients) and pH are soil chemistry attributes that affect agriculture and native ecosystems and are sensitive to climate variables such as rainfall and temperature.

Office of Environment and Heritage (OEH) has used the projections from NARCliM to provide updated information on the projected impacts of climate change on SOC, pH and sum of bases in the near future (2030) and far future (2070).

Research results

Absolute change in lower depth soil pH (left) and soil organic carbon (right) by 2070

  • NSW is projected to experience a change in important soil properties as a result of climate change.
  • Soil organic carbon stocks are projected to decline over most of the state in the near future, although a slight increase is projected over the western regions.
  • Soils in most of the eastern part of the state are projected to undergo an increase in pH (become more alkaline), while the western region’s soils are projected to undergo a considerable decrease in pH (become more acidic). 

If you are interested in the spatial data for pH, soil organic carbon or sum of bases please contact us at

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Biodiversity Technical Report
Biodiversity Technical Report
Biodiversity Technical Report
Soil pH Maps

ASHX - 7.7 mb

Biodiversity Technical Report
Soil Organic Carbon Maps

ASHX - 6.8 mb

Biodiversity Technical Report
Soil Sum of Bases Maps

ASHX - 8.9 mb

What is Soil Organic Carbon, pH and Sum of Bases?

Soil organic carbon (SOC) is one of the most widely used indicators of soil health. It is associated with many chemically and physically desirable attributes including high biological activity, nutrient availability, soil physical structure, water holding capacity and aeration. SOC is also important for its potential role in contributing to climate change mitigation.

The soil pH is a measure of the acidity or alkalinity in soils. The soil pH can influence plant growth by its effect on activity of beneficial microorganisms that decompose soil organic matter and are hindered in strong acid soils.

Sum of Bases is a soil property that represents the level of macro-nutrients in the soil. Higher levels of macro-nutrients indicate more fertile soils and increased agricultural productivity. Sum of bases is the sum of the calcium (Ca), magnesium (Mg), potassium (K) and sodium (Na) in the fine material fraction (<2 mm) of the soil.