Wet conditions in 2022 delayed the start of a new project that aims to explore the use of stripper-disc systems to reduce stubble loads in south-west Victoria and Tasmania. In these high-rainfall zones, stubble can reach levels as high as 15 tonnes per hectare.

The high stubble loads mean that many growers use conventional header fronts when harvesting and burn cereal stubble prior to seeding or bail the excess straw. Some growers will plough stubble to reduce loads further if the burn was poor.

However, most growers remark that if there were any other options besides burning that they could use to reduce their stubble loads effectively and economically, they would be doing them.

This project will explore grower interest in stripper-disc systems and their viability in the high-rainfall zones. Talks with growers and agronomists are ongoing to establish quality trials that are relevant to growers’ interests and current practices.

Recently, the first stripper front trial was established at Willaura. It will look at three factors:

1. header front type (stripper versus conventional);

2. stubble management practice (retained versus incorporated); and

3. seeder type (disc versus tyne).

All involved with the trial have been impressed with the stripper front and its efficiency in harvesting a lodged wheat crop. However, the manner in which longer stubble affects operations and the crop over the next two seasons will be the real test.

Issues that need to be explored include concerns around there being fewer herbicide chemistry options when using disc seeders. This is critical since weeds are a massive issue for growers in the high-rainfall zones and several newer chemistry options are not on-label to be used with disc seeders due to lack of separation between chemical and seed.

Establishment rates with disc seeders versus tynes will also need to be closely examined since disc seeders can more easily pull through stubble without it getting caught and dragging. In wet conditions, that can cause discs seeders to just make a slot for the seed, whereas tynes are able to get a bit deeper to create a furrow, which is a better seedbed.

Trials interrupted

The planned field trials for 2022 had to be delayed as the paddocks selected for this work fell through at the last minute due to circumstances beyond anyone’s control. For example, the project experienced a heavy rain event the day before a paddock was to be sown, which resulted in the paddock being inaccessible to seeders.

Due to the lateness in the season and potential further accessibility issues, it was agreed that the trials would be relocated to paddocks that were due to be sown in the spring. In Tasmania in particular, spring sowing is very common, particularly into barley. While it is less common in south-west Victoria, spring sowing is quite prevalent.

More information: Audrey Gripper, agripper@sfs.org.au