GRDC stubble management guideline No. 3
Stubble management begins at harvest. Many of the issues that arise when stubble is retained, such as seeder blockages, reduced herbicide efficacy and poor crop establishment, can be avoided if thought is given to the type of stubble that needs to be produced by the harvest process.
The type of stubble (length, load and distribution) that a grower aims to leave behind after harvest will largely depend on yield environment, seeding equipment, the paddock’s pest, weed and disease burdens and the crop they plan to sow the following year. However, generally speaking, uniform stubble and evenly spread crop residue will improve outcomes in a retained stubble system.
Time and care is required to produce stubble with characteristics that are ideal, but this must be balanced against the primary objective of harvest which is to get the crop off within the optimum window and before any inclement weather which may impact yield and quality.
Stubble height is one factor that may vary with the season, rotation and harvest logistics.
Cutting the crop high will improve harvest efficiency, but it may be necessary to reduce stubble height before sowing and/or summer spraying, to achieve adequate spray efficacy, improved crop emergence and to ensure sowing has a better chance of being timely and trouble free.
Conversely, setting the cutter bar on the header closer to the ground (commonly used rule-of-thumb is equivalent to, or less than, the row spacing) will minimise the need to manage stubbles after harvest but will make harvest slower, putting ripe crops at an increased risk of weather damage and quality and yield loss.
As part of the ‘maintaining profitable farming systems with retained stubble in Victoria and Tasmania’ project Birchip Cropping Group (BCG), Southern Farming Systems (SFS), Irrigated Cropping Council (ICC) and the Victorian No Till Farmers Association (VNTFA) have been working to establish guidelines for farmers seeking to create stubble with characteristics appropriate to their farming system. This guideline links closely with Guideline 4 which discusses machinery selection, set-up and operation in a retained stubble farming system.
Findings from field trials and demonstrations carried out as part of this project as well as previous research and anecdotal evidence from leading farmers and consultants, has been considered in developing regionally specific guidelines for irrigators and farmers operating in the Wimmera and Mallee.