Grazing crops in a dry year

DAFWA, GRDC - Philip Barrett-Lennard, agVivo; Richard Quinlan, Planfarm; Sam Taylor, agVivo; Greg Warren and Michelle Handley, Farm & General and Ryan Pearce, ConsultAg.

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

Very insightful and well presented trial results.

What was the problem?

There is growing interest in managing the grazing of crops in winter. The aim of the research was to determine the impacts of grazing on yield and quality.

What did the research involve?

  • 11 farm trial sites were established across the WA wheatbelt from Badgingarra to Esperance.
  • Farmers sowed and managed crops as per their usual farm practice, using a range of cereal and canola varieties.
  • Temporary electric fencing was used to divide each paddock into grazed and ungrazed areas.
  • Crop growth stage and biomass were recorded when livestock went in and out of the paddock. Weeds and disease levels were recorded on a regular basis throughout the growing season.
  • Crop yield was determined by either (a) using yield monitor data from the harvester, or (b) using yield data from small plot harvesters.
  • Animal grazing data has been standardised into DSE grazing days per hectare using a standard set of conversion rates. All crops were grazed by sheep except the two Gibson crops which were grazed by cattle.

What were the key findings?

  •  Grazing days, expressed as DSE grazing days per hectare, ranged from 110 to 307.
  • Grazing of cereal and canola crops in winter reduced grain yield by between 8 and 21% at seven of eleven sites. Grain yield was unaffected by grazing at four of eleven sites.
  • Late and/or heavy grazing of a crop increases the risk of incurring a yield penalty. Low rainfall may also be a factor.
Crop grazing data of 11 grazing crop trials conducted throughout WA in 2012 Source: DAFWA, GRDC
Grain yield and quality of 11 grazing crop trials conducted throughout WA in 2012 Source: DAFWA, GRDC
Change in grain yield and factors thought to influence crop recovery after grazing, Source: DAFWA, GRDC

Final comment

Have to remember that when grain prices were high, a small yield penalty caused by crop grazing can  have a large impact on grain income per hectare.

2014 - Australia - DAFWA, GRDC - Philip Barrett-Lennard, agVivo; Richard Quinlan, Planfarm; Sam Taylor, agVivo; Greg Warren and Michelle Handley, Farm & General and Ryan Pearce, ConsultAg.
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