Managing soil organic matter

Do agricultural management practices influence soil organic carbon and as a result soil function important to production?







  • Department of Primary Industries and Regional Development
  • Grains Research and Development Corporation
  • Australian Government Department of Agriculture

Project team

  • Frances Hoyle

Project overview

Subsoil constraints cost WA growers more than $600 million each year in lost production (Herbert 2009). These include acidity, nutrient disorders (deficiencies, toxicities), compaction, sodicity, waterlogging and salinity. Often one or more of these constraints are present and can decrease root depth and function to the extent that yield penalties are incurred. Current diagnostics are often insufficient or cost prohibitive on a large scale. Being better able to predict the extent and severity of these constraints, as well as the evidence in ameliorating these soils would enable growers to more confidently and accurately identify and assess management and/or mitigation options for their circumstance.

The project achieve state-wide coverage through partnerships with grower groups and extension specialists in the northern (Liebe, West Midlands, Mingenew Irwin Groups), central (MADFIG, Kellerberrin, Bodallin, Facey, Corrigin, LIFT) and southern (RAIN, SEPWA, FBG, Stirlings to Coast, North Stirlings, Bugs and Biology) wheatbelt of WA.

How is the research being used?

  • Soil type, climate and to a lesser extent management define the limits to soil organic carbon stocks in agricultural soils.
  • At higher temperatures with adequate soil moisture, decomposition of soil organic carbon occurs rapidly. Temperature is a key determinant of the ability of WA agricultural soils to retain carbon.
  • Strategic tillage typically results in a redistribution and often a loss of soil organic carbon from the top 10cm where it’s typically concentrated.
  • Changes in soil organic carbon are decadal and it can take decades to measure change.
  • Soil organic carbon is critical to many underlying functions of soil such as nutrient and water supply, as well as resilience to stress

Project publications