Seeding rate by row spacing for barley grass management


Research organisatons
Funding source

Trial details

Researcher(s) Amanda Cook (SARDI)
Year(s) 2016
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Site 16, Minnipa Agricultural Centre, SA
Seeding rate by row spacing for barley grass management locations

To investigate the potential non-chemical options for managing barley grass in a crop is increasing crop competition by reducing row spacing and increasing sowing rate.

Key messages
  • Reducing row spacing to 18 cm from 30 cm increased grain yield of wheat by more than 0.5 t/ha in 2015 and 2016.
  • Increasing seeding rate also increased grain yield in 2015 and 2016.
  • Late grassy weed dry matter was 65% lower, and barley grass weed seed set was 57% lower, with a higher seeding rate.
  • 18 cm row spacing had 42% lower grass weed dry matter than 30 cm row spacing.
  • Single row or spread row seeding boots showed little differences in plant establishment, grain yield and quality or grass weed competition.
Lead research organisation Eyre Peninsula Agricultural Research Foundation
Host research organisation N/A
Trial funding source GRDC CWF00020
Related program Overdependence on agrochemicals

Thank you to Sue Budarick, Tegan Watts and Katrina Brands for doing the weed counts. Funded by the GRDC Overdependence on Agrochemicals project (CWF00020).

Other trial partners Upper North Farming Systems
Download the trial report to view additional trial information


Crop type Wheat
Treatment type(s)
  • Sowing: Rate
  • Sowing: Method
  • Sowing: Row spacing
Trial type Experimental
Trial design Replicated

Minnipa Agricultural Centre 2016

Sow rate or Target density 60, 120 or 240 plants/m2
Sowing machinery

single row Harrington point vs Atom Jet spread row seeding boot with press wheels

Sow date 18 May 2016
Harvest date 4 November 2016
Plot size 20m x 2m
Plot replication 4

60 kg/ha of 18:20:0:0


The trial was sprayed on 16 May with a knockdown of 1.5 L/ha of glyphosate, 1.5 L/ha of trifluralin and 80 ml/ha of carfentrazone-ethyl. and broad-leaved weeds were controlled on 24 August after sampling.


An insecticide was sprayed on 22 June

Download the trial report to view additional method/treatment information
Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Site Depth Type pH EC P K N A OC CAT
Site 16, Minnipa Agricultural Centre, SA 0 - 10cm 7.80 33.00 151.00
Site 16, Minnipa Agricultural Centre, SA 0 - 30cm 7.80 33.00 151.00
Site 16, Minnipa Agricultural Centre, SA 0 - 90cm 7.80 33.00 151.00
Soil conditions
Trial site Soil texture
Site 16, Minnipa Agricultural Centre, SA Red sandy loam
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 16, Minnipa Agricultural Centre, SA Calcarosol
National soil grid Source
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties



Site 16, Minnipa Agricultural Centre SA 2016

Observed climate information

Rainfall avg ann (mm) 325mm
Rainfall avg gsr (mm) 241mm
Rainfall trial total (mm) 391mm
Rainfall trial gsr (mm) 268mm

Derived climate information

Site 16, Minnipa Agricultural Centre SA


Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from
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.

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Trial last modified: 08-10-2019 14:49pm AEST