Sugarcane subsoil management for improvement of carbon and nitrogen use efficiency

Australian sugarcane farmers face declining productivity and sustainability due to deteriorating subsoil conditions. This project aims to enhance carbon and nitrogen use efficiency and increase sugarcane yield through subsoil management, specifically by applying organic amendments (e.g. compost, mill mud, manure). This innovative approach is expected to boost soil organic matter, nutrient supply, physical structure, water retention, microbial activity, and pH buffering capacity in the sugarcane rhizosphere.
Key project objectives include: 1) Assessing the impact of subsoil organic amendments on carbon and nitrogen use efficiency in sugarcane systems. 2) Evaluating subsoil health through comprehensive physical, chemical, and biological indicators. 3) Establishing a positive relationship between improved subsoil conditions and increased sugarcane yield.

The project will leverage Griffith University’s research facilities, Sugar Research Australia and Burdekin Productivity Services’ field management, and the Department of Agriculture and Fisheries’ life cycle cost analysis expertise. Project outputs include scientific publications, practical protocols, technical reports, and training workshops. Anticipated short-to-medium-term outcomes are an adoption rate of up to 50% of growers in target regions, leading to increased farmers’ income, enhanced employment opportunities, and reduced environmental impacts. Long-term benefits include sustainable agricultural practices, improved subsoil conditions, and significantly higher productivity in the Australian sugarcane industry.

Acknowledgement
This project is fully funded by the Department of Primary Industries and managed by Sugar Research Australia.

The proposed project aims to explore the effects of applying organic amendments to subsoil, both alone and combined with chemical nitrogen fertilisers, on improving carbon and nitrogen use efficiency and sugarcane yield. By thoroughly assessing the agronomic, environmental, and economic benefits of organic amendments, especially in soils with low organic matter and poor subsoil conditions, this study seeks to enhance the sustainability of Australian sugarcane farming.

The primary objectives of the project include:
1) To assess the impact of subsoil application of organic amendments on carbon and nitrogen use efficiency in sugarcane cropping systems.
2) To utilise comprehensive soil physical, chemical, and biological indicators to assess soil health in response to subsoil application of organic amendments.
3) To establish a reliable and positive relationship between the improvement of soil health conditions and the increase in sugarcane yield.

This research will equip end-users like farmers, agronomists, and policymakers with robust, evidence-based management strategies for optimising soil health, carbon and nitrogen use efficiency, and boosting sugarcane yield, especially in regions characterised by poor soil organic matter and adverse subsoil conditions. The findings will inform policy and decision-making to foster long-term sustainability and productivity in Australian sugarcane system.