GRDC stubble management guideline: No. 8
The effective management of stubble during a fallow period (the period when no crop is growing in the paddock) can minimise a number of potential cropping issues such as weed populations, seeder blockages and erosion. Effective fallow management can also lead to improvements in crop emergence, crop nutrition, soil structure, soil moisture retention and crop yields.
Management practices carried out during the fallow period, such as herbicide applications, grazing and burning, will influence the level of soil moisture and nutrients that can benefit the subsequent crop. One of the messages to come out of the GRDC’s five-year Water Use Efficiency project (BWD00012), was that management decisions which take place before a crop is planted can have a greater influence on crop performance than in-crop management decisions (Hunt J. et al, 2014). This message holds true when considering stubble management and the management of fallows.
To harness the benefits of a retained stubble system, monitoring and management of fallow paddocks is critical. While thinking ahead to the next crop to be grown in the paddock, growers need to consider the current stubble load and how this will influence sowing, crop emergence, herbicide efficacy and disease and pest levels.
Producers with sheep may also need to weigh up the value of grazing fallow paddocks against any trade-offs such as ground cover reduction, weed control and the flow on effects on stored soil water and nutrients (McClelland T., 2012).
As part of the ‘maintaining profitable farming systems with retained stubble in Victoria and Tasmania’ project the Birchip Cropping Group (BCG), Southern Farming Systems (SFS), Irrigated Cropping Council (ICC) and the Victorian No-Till Farmers Association (VNTFA) have been investigating effective fallow management techniques in retained stubble farming systems.
Findings from field trials and demonstrations carried out as part of this project as well as previous research (including the ‘Protecting Mallee soils over summer’ project, which commissioned the YouTube clip below) and anecdotal evidence from leading farmers and consultants, has been considered in developing these guidelines.
Wimmera and Mallee farmers can access a regionally specific information about fallow management in a retained stubble system here.