Source: GRDC The Crop Doctor

The re-emerging profitability of livestock, particularly lambs, has focused attention of cereal crops as a grazing option. There's plenty of anecdotal evidence about wheat out-performing oats and of grazed grain crops out-yielding those that haven't been grazed but there's very little hard data to support management practices.

Professor Ted Wolfe of Charles Sturt University, who spoke about grazing cereals during the recent series of GRDC updates held in February, has been re-visiting the information gained from three sets of grazing experiments done at NSW DPI's Temora Research and Advisory Station, two of them going as far back as 30 years ago. While the varieties studied have passed their use-by date the management principles developed as a result of those trials are still current. The experiments were particularly valuable because, as they were conducted over a number of years, we have the chance to look at the impact of grazing in good and bad years.

Oats, barley and wheat were compared over the course of the experiments. Dual-purpose (grazing and grain) cultivars of these cereals were sown from mid-March to April and were grazed either at 20 or 30 hoggets per hectare with grazing starting early in the season (June) or late (July).

Professor Wolfe sums up the work by saying that in the wheat sheep zone grazing early sown cereals not only fills the June-July feed gap but the winter gains from grazing cereals are better than those obtained from unsaved pasture, and the grazed crop can even benefit the stock that never see it. Reducing the grazing pressure across the rest of the farm means more pasture to go around.

It's important to sow a dual-purpose variety, wheat, oats or triticale that has a winter habit early in the season, late March or April, and to sow plenty of seed. Seeding rate was more important in producing early feed than the cultivar, Ted found. In a good year the crop was ready for grazing 45 to 65 days after sowing.

The target is one tonne of green, dry matter per hectare but the rule of thumb is that if the crop is as high as the top of your riding boot and it has good anchorage, it's right to graze. Many agronomists delay grazing but Professor Wolfe found that farmers usually get it right and get the stock on early.

Of course there was a difference in production between good and bad years but even in drought years the hoggets on the cereal out performed their brothers on what pasture was available. At their best they gained as much as 3kg per fortnight when they first went onto the crop and were still gaining better than 2kg a fortnight at the end of eight weeks grazing. In the dry, autumn, winter of 1976 they initially barely held their own on barley and no matter what the crop, had to be taken off when they were losing weight after six weeks. The differences between the cereals in herbage and sheep production were small, but the newer varieties of wheat and triticale stood out for their grain potential.

In the best years of the trials the cereal crop grew away from the stock even at heavy stocking rates and in the drought years the crop was eaten down to ground level after just four weeks, but the amount of herbage remaining after grazing didn't seem to have much effect on grain yield. The important factor was to remove stock soon after the reproductive growing point was initiated, and before the growing point started to elongate upward from the ground surface. At Temora, the best time to remove the sheep was from mid-late July. Farmers and agronomists should begin dissecting tillers to check on the position of the growing point around this time.

Professor Wolfe suggests that, for grain production, it's the number of plants per hectare and the number of tillers per plant that are more important than the grazing pressure. Plant numbers can be reduced by grazing too early, and tillers by grazing too late. At harvest, there should be about 60 plants per sq metre and six to eight fertile tillers per plant.

He categorically dismisses the practice of rotational grazing. Early sown cereal crops, he says should give growers 6-8 weeks of continuous grazing at stocking rates of 20 DSE. Set stocking or the 'put and take' system adopted by most farmers is the way to go.

Producers this year who want to graze a grain crop have another couple of variables to consider. Plague locusts are already active around southern NSW and northern Victoria, so a March-April sown cereal crop could face some very competitive grazing. The outbreak of stripe rust has reduced the availability of suitable early sown dual-purpose wheat varieties and if susceptible or moderately susceptible varieties are sown with a seed dressing protection there are withholding periods to consider before grazing. It is best to calculate carefully the expected supply-demand position for winter feed, since there is no money made if the extra feed is not needed. If the weather continues on into a dry autumn, purchased fodder might be a better option. Ask respected local agronomists for their recommendations.

The Crop Doctor is GRDC Managing Director, Peter Reading