Making the most from dual-purpose crops

It's the middle of the dual-purpose crop grazing season, making it the ideal time to consider how to maximise their value in a mixed farming enterprise.

While wheat is a commonly grazed crop, canola is emerging as a valuable addition to the feed mix and can provide 700-2,300 sheep grazing days per hectare. Research shows that dual-purpose canola provides a high quality feed for ewes, which gives producers flexibility in their crop rotations because they can use canola as a break-crop to manage weeds and diseases as well as fill the autumn and winter feed gap.

CSIRO, Charles Sturt University (CSU) and Victorian State Government researchers are developing guidelines to grow and graze dual-purpose crops, using MLA-funded trial sites in the NSW Tablelands, Riverina and south-west Victoria.

The researchers’ top five tips for grazing dual purpose crops are:

Assess how dual-purpose crops could benefit your system:

• Feed options: Adding dual-purpose crops to a grazing system gives producers the chance to spell permanent pastures, can reduce the autumn/winter feed gap and could also reduce supplement costs.
• Stocking rates: dual-purpose crops allow an increase in winter stocking rates.
• Growth targets: In the experiments, ewes and weaners grazing wheat and canola had larger weight gains than the sheep that only grazed pasture.
• Economics: Trials that included dual-purpose crops had higher gross margins (by 38–65%) than the trial where stock only grazed pasture.

Understand nutrition:

• Supplements: Mineral supplements are not necessary for sheep grazing canola. However, the mineral profile of wheat is very different, with low sodium, marginal magnesium and variable levels of calcium, so it is recommended that ewes grazing dual-purpose wheat be provided a mineral supplement that includes magnesium, calcium and salt to reduce the risk of metabolic diseases such as hypocalcaemia and hypomagnesaemia (grass tetany).
• Hay: Fibre content of canola is lower than wheat, so producers should consider providing additional fibre such as hay for livestock grazing brassica crops.

Maintain body condition:

When grazing late-pregnant and lambing ewes on dual-purpose crops, ensure ewes are in adequate body condition score coming into lambing (BCS ≥ 3) to reduce the risk of metabolic diseases.

Embrace the dual benefits of dual-purpose crops:

Grazing crops does not have to come at the cost of grain production. Autumn and winter grazing of wheat and canola on the NSW Tablelands and in south-west Victoria had no effects on grain yield.

Follow agronomic best practice:

• Sow dual-purpose crops early to match the window of opportunity for grazing without affecting grain yield.
• Canola should be grazed only when plants are well anchored (6-leaf stage).
• Remove stock from canola by July when crop is at mid-dormant stage so it can recover for harvest.
• Comply with chemical withholding periods before grazing dual-purpose crops.

Information:

• NSW Tablelands research: Cesar Pinares-Patino, CSIRO, Cesar.Pinarespatino@csiro.au
• NSW Riverina research: Shawn McGrath, Charles Sturt University, shmcgrath@csu.edu.au
• SW Victoria research: Maggie Raeside, DEDJTR, Margaret.Raeside@ecodev.vic.gov.au
• Download Canola best practice management guide for south-eastern Australia