TRIALS have shown farmers in the Wimmera and Mallee can graze cereals using similar rules of thumb to those employed in higher-rainfall zones.
Birchip Cropping Group extension manager Fiona Best said paddock-scale trials at Rainbow found grazing sheep on cereals between growth stage 13 and 30 delivered a better gross margin and no yield penalty, but increased the level of screenings.
Ms Best delivered results of last year's research trials to a forum of BCG members last week.
She said the grazing trials compared the performance of hindmarsh barley and Clearfield stiletto wheat.
The paddocks were sown according to the farmer's usual practice and at a time that fitted their program, then a 1ha plot in each paddock was fenced off to allow controlled grazing.
Samples were taken for dry matter and feed tests before grazing.
Using a formula, it was calculated that each dry sheep equivalent would require eight megajoules of energy per day.
Ms Best said the only rule was that stock had to be introduced as the crop reached growth stage 13-15 and removed before growth stage 30, using the adjacent crop growing as a guide.
One paddock was crash-grazed for three days with 100 ewes and another 200 ewes were added for two days before they were all removed, equivalent to 900 DSE days of grazing.
One paddock was stocked with 14 dry ewes for nine days, or 126 DSE days of grazing.
One paddock was stocked with 11 wethers for 14 days, or 154 DSE days of grazing.
And the fourth paddock was crash-grazed by 320 weaner ewes for three days, or 960 DSE days of grazing.
Ms Best said none of the grazing strategies made any difference to crop recovery and post-harvest feed tests produced similar results for all four paddocks.
Based on a price of $200 a tonne, feed values were calculated at $12.55/ha, $17.20/ha, $18/ha and $24/ha.
"While the data could not be statistically assessed, there was a trend of higher screenings in the grazed areas which is supported by BCG's replicated trial work (at Woomelang)," Ms Best said.
"It should be noted that the paddocks that were crash-grazed exceeded the theoretical amount of DSE days and it could be assumed that grazing under this regime would have caused stock to lose condition.
"The additional dollars associated with feed value would increase the gross margins achieved by farms in situations where supplementary feeding would otherwise have been required, particularly because no yield penalty was incurred."
BCG trial work undertaken at Woomelang last year found yield response to grazing was variety dependent and some commonly grown varieties could suffer a yield penalty in the Mallee.
'"Despite not being particularly evident in these farmer demonstrations, additional rules likely to apply to this region may be to only graze crops that are sown early - before May 15 - and to avoid grazing shorter season varieties," Ms Best said.
