Can wheat on wheat cropping rotations be sustainable 2015 trial report

Page last updated: Tuesday, 26 April 2016 - 4:01pm

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We all know the risks involved with continuous cropping particularly the risks involved with a wheat on wheat rotation.

We also know the benefits of a robust crop rotation in a farming system. Despite this, growers in the central wheatbelt often favour a wheat on wheat rotation.

Over four seasons, the Department of Agriculture and Food, Western Australia's (DAFWA) wheat project will explore the ways that this type of rotation can be sustainable in the cropping system.

In areas of lower rainfall cereal on cereal rotations are seen as a way to make a profit without the risks involved in sowing a break crop such as canola.

The Merredin district has been selected for this trial series as continuous wheat is practised in this area. It is interesting to note that currently, most wheat on wheat rotations have been observed on medium to heavy soils but is most profitable on medium soils.

Continuous wheat on wheat cropping can become unproductive due to excessive build-up of weeds (wild radish, brome grass and ryegrass) and cereal diseases which often require a breakcrop or applications of various chemicals which can be costly.

This trial series has been designed to ;

  • measure the constraints to wheat production in continuous sequences in the eastern Wheatbelt
  • work out how different wheat varieties respond to those constraints
  • come up with management options to minimise the effects of these responses.

Trial details

Table 1 Trial details
Sowing date 17 June
Fertiliser and chemical at seeding

Agras 100kg/ha below seed

Talstar100mL/ha post seeding

Fertiliser and chemical during the season

Monitor for weeds, pests and disease throughout the season and treat accordingly.

Flexi-N 47.5L/ha (20 N kg/ha) when wheat is tillering.

Atrazine 1.1kg/ha to canola at 2-6 leaf stage.

Spray out fallow plots with glyphosate once there is sufficient ground cover to protect soil surface.

Crop treatments (crop sequences)

Main plot treatments (crop sequences):

  1. Continuous wheat
  2. Fallow-wheat-wheat-wheat
  3. Canola-wheat-wheat-wheat
  4. Fallow-canola-wheat-wheat
  5. Canola-fallow-wheat-wheat
  6. Wheat-fallow-canola-wheat

There will be three instances of each of these sequences, one each using Mace, Emu Rock, and Magenta wheat.


Results from this trial will be updated throughout the year.


The Grain Crop Agronomy Reference group, managed by Grains Research and Development Corporation (GRDC), for their support with research development in 2015. DAFWA’s research support unit at Merredin for trial management and DAFWA’s Bruce Haig for technical support.

The project ‘Tactical wheat agronomy for the west (DAW00249) is jointly funded by GRDC and DAFWA.


Georgia Trainor