Growing Competitive Sorghum and Mungbean Crops to Suppress Summer Weeds

GRDC - Author: Michael Widderick (Queensland Department of Agriculture and Fisheries), Adam McKiernan (Queensland Department of Agriculture and Fisheries), Greg Harvey (Queensland Department of Agriculture and Fisheries), Linda Heuke (University of Sydney), Michael Walsh (University of Sydney) and Asad Shabbir (University of Sydney)

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The authors of this paper note in the conclusion: “Our research shows there are weed control benefits in growing competitive sorghum and mungbean crops. Although some of the findings have differed between trials and seasons, results show narrow row spacing can improve competitiveness for both crops and is the approach that will likely have the largest and most consistent impact on weed growth and seed production. Increasing sorghum plant density also consistently increased the competitive effects of this crop against these weeds, whereas mungbean density had less impact. Cultivar choice may have an impact in both crops but is likely to be dependent upon seasonal conditions. Favourably, our results show that growing a competitive crop not only reduces weed competition and seed set but can improve or maintain crop yield.”. Please access the full paper via the link below if this research interests you.

The take home messages from this GRDC  funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.

  • Feathertop Rhodes grass (FTR) and awnless barnyard grass (ABG) are both difficult to control summer grass weeds with both species prone to herbicide resistance evolution
  • Growing a competitive sorghum or mungbean crop can reduce growth and seed production of FTR and ABG
  • ABG is more susceptible to the impacts of crop competition than FTR
  • Sorghum competitiveness can be increased by growing the crop at a narrow row spacing (50 cm) and increased density (10 to 15 plants/m2)
  • Mungbean competitiveness is most effectively increased through the use of narrow row spacing (25 and 50 cm)
  • Consider growing a competitive summer crop to take pressure off relying solely on in-crop herbicides for summer grass control.

Figure 4. Effect of sorghum row spacing and crop density on awnless barnyard grass biomass. Narrabri, NSW 2017/18. Data points with a different letter are significantly different (P=0.05). LSD = 24.7.

2020 - Australia - GRDC - Author: Michael Widderick (Queensland Department of Agriculture and Fisheries), Adam McKiernan (Queensland Department of Agriculture and Fisheries), Greg Harvey (Queensland Department of Agriculture and Fisheries), Linda Heuke (University of Sydney), Michael Walsh (University of Sydney) and Asad Shabbir (University of Sydney)
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