Soil Properties

Many soil properties are sensitive to climate variables such as rainfall and temperature.

Using regional climate projections from the NSW and ACT Regional Climate Model project, NARCliM, the Office of Environment and Heritage (OEH) has examined the expected impacts of climate change on three important soil properties in the near future (centered around 2030) and far future (centered around 2070).

Understanding how soil properties will change over the coming decades can help guide the management of soils and associated agricultural and native ecosystem landscapes in NSW.

Research results

Results from improved modelling programs are presented here, with associated second edition reports and maps, updating results from the 2015 modelling program.

Absolute change in upper depth (0-30 cm) for soil organic carbon stocks (left) and pH (right) by 2070

Three important soil properties will be impacted by projected climate change in New South Wales:

  • The amount of organic carbon stored in soils will decline over most of the state, with the most dramatic declines in highland regions.
  • Soil pH is projected to increase (becoming more alkaline) over the entire state, with the largest increases in the southern alpine region.
  • A subset of macro-nutrients in soils (sum-of-bases) is projected to increase over the entire state, with the largest increases in the southern alpine region.

These changes are applicable over both 0-30 cm and 30-100 cm depth intervals.

The modelling did not consider the influence from ongoing land management, such as potential acidification and nutrient decline from intensive agricultural practices.

If you are interested in the spatial model data produced in this study for soil organic carbon, pH or sum-of-bases, please contact us at narclim@environment.nsw.gov.au.

Download information

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

ZIP - 1.6 mb

Biodiversity Technical Report
Soil Sum of Bases Maps

ZIP - 1.8 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 quantity of a set 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.