13 March 2007
Trial results for the Grain and Graze and National Landcare Programs suggests there's a substantial and untapped store of early winter grazing in paddocks of wheat, barley and triticale sown for grain.
The trial in Western Victoria showed grazing Yerong barley at the vegetative growth stages - up to stem elongation:
� had no adverse effect on eventual grain yield and even improved yield slightly,
� reduced stubble levels slightly, promising easier sowing in the following season, and
� reduced the need to graze new or re-germinating legume pastures in early winter.
Grazing at or after the start of stem elongation provided more dry matter for livestock, and dramatically decreased stubble loads, but came at significant loss of grain yield.
Grain & Graze Corangamite/Glenelg Hopkins Regional Co-ordinator, Cam Nicholson, carried out the trial on the Shawcross family's property at Ceres, near Geelong, and he suggests "some caution" about the results, given the very dry conditions during the growing season and inherent soil variability across the 10 hectare trial site.
However Mr Nicholson also points out that a review of the results of more than a dozen other trials, in different locations and times of the year and with different cereal varieties, tends to confirm those of the 2006 work at Ceres.
And that's why he's excited about the potential of his findings to provide considerable benefits to the whole farm system, not only in extra grazing but also in the effects on stubble loads and grain quantity and quality.
"Stocked with 56 first cross ewes with 114 per cent lambs at foot, the 10.4 hectare paddock was grazed for 47 days at an average stocking rate of 19.4 dry sheep equivalents per hectare (DSE/ha) over the grazing period, or 2.5 DSE/ha over the entire year," Mr Nicholson said.
"That grazing value from crop was significant given the dry year.
"For a typical farm in South West Victoria with an average stocking rate of 15.8 DSEs per hectare over a year, this grazing represents 16 per cent of total feed requirement for the year and is provided at a time of year when feed is in short supply."
Mr Nicholson said the trial paddock was divided into six areas of decreasing size after sowing, to provide a relatively constant period of grazing in each plot of between seven and 10 days.
Sheep were offered a larger area in the early grazed plots, as less feed per hectare was on offer, and the grazing area reduced in size as more feed per hectare became available. Five areas were excluded from the last grazed area to provide a no grazing benchmark.
The extremely dry conditions cut the amount of dry matter grown in the early vegetative stage, with only 32.5 millimetres of rain falling between the start of grazing on July 26 and the end of the fourth grazing on August 30.
"Most of that 32.5 millimetres fell on August 24 and 25, explaining the lack of growth up to then but the crop really jumped away after the rain to average 165 kg/ha/day to mid September" Mr Nicholson said.
"The quality of the feed on offer also changed dramatically during the grazing period, with energy rising from 12.5 megajoules of metabolisable energy per kilogram (MJ ME/kg) at Growth Stage 22 to 13.5 MJ ME/kg at Growth Stage 30, before declining.
"The opposite occurred with the protein in the crop. Protein was highest at Growth Stage 22 (36.7%) but declined rapidly over the grazing period to 19.6% at Growth Stage 32."
Mr Nicholson said the research team believed a number of influences from grazing had contributed to the trial's overall results.
Early removal of leaf during a dry winter would have conserved soil moisture for later use by the crop, with this response greatest when the crop was grazed at the late vegetative stage, where a gain of 0.86 t/ha or 39% was achieved over the no grazing areas.
The delay of ear emergence by seven to 10 days could have helped avoid frost, while grazing also affected harvesting, with the no grazed plots ready for harvest 20 days before the late grazed (Growth Stage 32) ones.
"Visual observations would suggest some grain may have been lost as seed shaken from the heads, but this is highly unlikely to explain the total yield difference between the grazed and ungrazed plots," Mr Nicholson said.
"Grazing reduced the amount of stubble remaining after harvest, irrespective of the time of grazing; the greatest reductions occurred with grazing at Growth Stage 30 or later, but there was still a reduction in stubble yield with the earlier grazing at the vegetative stage."
For full research results of the grazing cereal trials in the Grain & Graze Corangamite/Glenelg Hopkins Region, contact Regional Coordinator, Cam Nicholson, on 03 5258 3860; and for more information on the National Grain & Graze Program, contact Richard Price, National Coordinator, on 02 6295 6300, mobile 0409 624 297; Gillian Stewart on 02 6263 6042; Lynne Sealie on 02 6263 6021 or visit www.grainandgraze.com.au.
Grain & Graze Regional Coordinators
Avon Region - Linda Leonard - 08 9690 2191
Border Rivers Region - Rachel Charles - 07 4671 7900
Central West/Lachlan Region - Jodie Dean - 02 6895 1015
Corangamite/Glenelg-Hopkins Region - Cam Nicholson - 03 5258 3860
Eyre Peninsula Region - Alison Frischke - 08 8680 6223
Mallee Region - Zubair Shahzad - 03 5021 9103
Maranoa/Balonne Region - Stephen Ginns - 07 4620 8122
Murrumbidgee Region - Katrina Sait - 02 6924 4633
Northern Agricultural Region - Philip Barrett-Lennard - 08 9475 0753