Frost management options to increase wheat grain quality and yield and how these strategies impact on soil erosion along the south coast of Western Australia

Timeframe: 2015

Funding sources: GRDC, COGGO, DPIRD

Project Coordinator: Sally Carpenter

Summary

The objective of this project was to assess the suitability of stubble management options for minimising frost damage in cereal crops in a medium production environment, with consideration of secondary effects such as soil erosion. Stubble management options included retained stubble, reduced stubble and removed stubble. The impact of each treatment was measured extensively to identify any benefits of stubble management to frost mitigation.

The trial was held in Jacup at Stu and Leeanne Bee’s property. The site experienced 20 frost events at canopy level (temperature dropped below 0°C) between August and November. The severest event reached -3.5°C in a retained stubble during September.

Of the 20 recorded frost events, there was no event that showed significant differences between the three stubble treatments for either severity or duration. Consequently, the results did not conclusively support the use of stubble management as an effective frost management tool in medium production environments.

Project details and outcomes

Photo monitoring showed no negative impact of stubble removal on soil erosion. This was likely caused by the mild climate experienced in the early stages of crop development. Additionally, stubble removal was held off until immediately prior to seeding to minimise wind erosion.

Frost induced sterility/FIS (frost damage) varied from 5% to 14% across the site and no significant difference was found between stubble treatments. Previous studies suggest that the lack of significant variation could be due to the small difference in stubble loads and a difference may be observed in high production environments where stubble loads are greater.

All stubble treatments exhibited similar harvest index components, suggesting minimal difference in frost damage which corresponds with the other data collected.

Yields were low across the site and statistical analysis of the yield map data showed no differences between stubble treatments. This is expected as there were no temperature, FIS or harvest index differences between the treatments.

The results of the trial were inconclusive in supporting the use of stubble management as an effective frost management tool in medium production environments. Stubble management is a well-known practice, which has been increasing in recent years, particularly along the south coast of Western Australia. Results from this trial may result in a decline in unnecessary stubble management in these regions.