Chris Wilkins &, Nathan Craig West Midlands Group
|Contributor||West Midlands Group|
Site 6, Merredin, WA
Including break crops into rotations with cereals can influence the nitrogen (N) dynamics of cropping systems and assist in the management of weeds and reduce disease incidence in crop rotations. Previous studies into single year break crops where herbicide-resistant annual ryegrass was present found that weeds still had a significant impact on wheat production. Interestingly, these trials demonstrated that clean fallow or break crops can deliver cheaper, more effective ryegrass control compared with in-crop grass management options in wheat.
Two break crops in a row has seen cereal yields double and grassy weeds drop in problem paddocks in low rainfall zones across South Australia. Pastures and break crops - such as pulses, canola, brown manure vetch and oaten hay – have been grown for up to two seasons and some of the results were outstanding. Despite very strong wheat yields in the first two years of the trial, disease and grassy weeds are now starting to reduce performance of continuous wheat. However, wheat following two year breaks are now producing gross margins several hundreds of dollars per hectare better than continuous wheat with no major constraints developing yet. One year breaks have improved the following wheat performance, but weeds and diseases are still present.
The main objective of this project is to demonstrate the rotational benefits of a sequence of broadleaf, legume, and pasture crops for the production of wheat in the Kwinana West and East zones of WA.
The results presented in this report are from the first year of a three-year study that investigates the effect of break-crop sequences on wheat grain yield. The site was selected due to its high background levels of ryegrass control, and crop rotation treatments have been designed around weed control as the main rotational factor.
Grain yield was relatively low compared to the growing season rainfall of 253 mm. Grain yield was affected by severe frost that occurred during grain fill.
This project will continue with the second crop in rotation for the 2017 season, followed by wheat across all plots in 2018 to assess the benefit of a stacked rotation for subsequent wheat grain yield.
|Lead research organisation||
West Midlands Group
|Host research organisation||
West Midlands Group
|Trial funding source||GRDC WMG00003-A|
|Other trial partners||GRDC|
|Sow rate or Target density||100kg/ha|
Knifepoint & presswheel
|Sow date||27 May 2016|
|Harvest date||18 November 2016|
|Plot size||2.88m x 12m|
|Fertiliser||<p>Summit Gusto (10N:12P:14K:7.5S + 0.5CU +0.1Zn) @ 80 kg/ha</p>|
|Seed treatment||Raxil® Pro|
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.