Can soil organic matter be increased in a continuous cropping system in the low to medium rainfall zone?

Authors: Harm van Rees¹ and Michael Moodie²

Research Team: Jeff Baldock³

¹Cropfacts P/L, ²Mallee Sustainable Farming, ³CSIRO

Funded By: GRDC CRF00002

Project Title: Improved management of soil organic matter and sustainable cropping

Peer Review: Jeff Baldock (CSIRO)

Key Words: organic matter, continuous cropping

Key Messages

• 8 trial sites were established across SE Australia to investigate whether soil carbon levels can be increased in No-Till farming practices by adding nutrients to aid the biological breakdown of stubble and stabilise carbon in soil organic matter.
• After 3 and 5 years of treatments no increase in soil carbon could be determined in any of the trials.
• We demonstrated that soil carbon is unlikely to increase with current farming practices, however No-Till and stubble retention protects the soil from wind and water erosion which is a major pathway for loss of organic carbon. Over the longer time-frame, stubble retention systems may be able to slow the rate of carbon loss.