Stubbles could offer grazing opportunity in weather-hit areas

STUBBLES from this year’s winter crops could provide a worthwhile grazing opportunity, especially in those parts of the southern cropping region hit by recent heavy rains, storms and frost.

A major collaborative research program has shown that winter crop stubbles containing residual grain and green shoots from shot grain and weeds can provide a valuable source of feed for livestock.

The Grain and Graze initiative, a Grains Research and Development Corporation (GRDC) joint investment, has demonstrated that animal weight is directly linked to the amount of grain and green materials in the stubble, assuming there is no supplementary feeding.

Recent weather events, including hail, heavy rain and frost, as well as damage from mice, are likely to result in higher than usual levels of grain left on the ground after harvest.

Winter crop stubbles in some locations, therefore, could offer a valuable resource for grazing if it is feasible to bring in livestock or if they are already part of a mixed farming system.

Grain and Graze project coordinator Cam Nicholson says “stubbles ain’t stubbles” when it comes to grazing value.

“Stubbles comprising standing straw and trash have much lower quality (energy and protein) which are below maintenance requirements for livestock,” Mr Nicholson said.

“Improved efficiency of harvest machinery means not all crop paddocks have grazing value and only those with sufficient high energy material should be grazed, otherwise sowing and herbicide efficacy problems can be created with livestock disturbing standing straw and covering weeds.”

Grain and Graze experiments indicate there needs to be at least 40 kilograms/hectare of residual cereal grain or 40 kg/ha of green material for a sheep to maintain or gain weight.

The equivalent of 40 kg/ha of cereal grain (13 grains per 0.1 metre square quadrant) for crop legumes is approximately four grains per 0.1 metre square quadrant for lupins, two for field peas and chickpeas and one for faba beans.

Forty kg/ha of green material is the equivalent of 14 green shoots per 0.1 metre square quadrant.

Mr Nicholson says below these values, animals lose weight, irrespective of how much straw or leaf trash remains.

He says other critical considerations when grazing stubble include:

• Grazing should be conducted to retain between 50 per cent and 70 pc groundcover so as to avoid wind erosion or a decrease in water infiltration
• In medium and low rainfall areas, removing green material in stubbles is recommended to conserve soil moisture, therefore only the residual grain should be considered as having long term grazing value
• Where mice have been an issue this year, grazing can also assist with removing grain left on the ground before, during and after harvest.