Dual-purpose crops boost pasture-only system

A four-year MLA-funded study assessing the benefits and risks of incorporating dual-purpose crops (DPC) in the southern tablelands of New South Wales has revealed they offer a flexible and profitable option for sheep producers looking to fill the winter feed gap and boost meat and wool production.

According to researcher Shawn McGrath, from the Fred Morley Centre at Charles Sturt University, results to date demonstrate that incorporating dual-purpose crops, namely wheat and canola, may not be as risky as many producers think, and most potential risks can be mitigated through management.

Less supplementary feeding was required in a poor year compared with a pasture-only system, even though the incorporation of crops into a pasture-based system reduces overall feed availability during early autumn.

“This particular study near Canberra investigated the integration of grazing wheat and canola into a traditional phalaris and clover-based system,” Shawn said.

“What we have seen is that when the timing of grazing is appropriately managed, grain production from dual-purpose crops is profitable in its own right — offering an additional source of income while also helping to fill the winter feed gap.

“The combination of wheat and canola offers additional grazing flexibility across variable seasons, and grazing crops sequentially can allow high livestock production and reset pastures for a significant period of the year.”

Research approach

The farming systems experiment started in 2013 and consisted of three treatments: pasture only (control) and pasture with DPC prioritised for grazing by either Merino ewes (ECG) or weaners (WCG).

Replicated farmlets were split into six paddocks (0.23ha each). Dual-purpose wheat and canola were rotated with ley pastures in four paddocks in the ECG and WCG treatments. Crops were sown during February or early March and grazed during late-autumn and winter.

The 2014 season was favourable, with no treatment differences in sheep live weight.  In contrast, 2013 and 2015 were poor or intermediate seasons.

“In these two years, ewes and weaners with partial or no access to the dual-purpose crops were heavier than their counterparts in the control treatment,” Shawn said.

Over the four years, priority grazing of ewes on crops reduced supplementary feeding when seasonal conditions were poor, and increased wool production by 16% (range 8 to 24%) or 0.7kg greasy fleece weight (GFW) per head compared with the control (phalaris x sub-clover based pasture). 

However, sale weight of lambs did not increase compared with the control. 

Priority grazing of weaners on dual-purpose crops increased wool production by 9% (range 5 to 13%) or 0.4kg GFW per ewe and increased average lamb production by 16% (range -1 to 30%) or 7.6kg live weight sold per weaner compared to a pasture-only system.

“Prioritising crop grazing for weaners also allowed other livestock classes (wethers or ewes) to graze the otherwise under-utilised crops during better seasons,” Shawn said.

Lessons learned

To optimise the grazing opportunities, the study highlighted the importance of sowing early.

“Getting the crops in the ground early, when sufficient soil moisture is available, maximises the opportunity to start grazing as early as April in some cases,” Shawn said.

In three out of four years, canola was the first crop to be grazed, but during 2015 canola establishment was slow and animals instead grazed wheat first.

“Having both crops in the system increased the flexibility under variable seasonal conditions,” Shawn said.  

It also meant that in 2015 the ewes grazed canola during lambing (July–August), with no apparent livestock health issues observed. 

Pushing the envelope

Project leader Andrew Moore, CSIRO, suggests the project has the potential to allow the best producers to push the envelope and ramp up their whole-farm system.

“The project aims to change aspirations of livestock producers who haven’t yet

adopted dual-purpose crops and refine practices of those who already utilise the valuable winter feed option,” Andrew said.

As part of the extension process, the research team is in the process of developing producer guidelines to help livestock producers maximise the opportunities and minimise the pitfalls associated with introducing crops into a grazing system.

“The guidelines outline the underpinning management principles and activities to enable high-utilisation rates of meat production per kilogram of forage eaten,” Shawn said.

The focus is unashamedly on the forage side of the dual-purpose equation, with a plethora of resources already available for grain growers looking to balance grain production with opportunistic grazing opportunities through GRDC’s Graze and Grain program.

“At the end of the day the key to optimising grain production from dual-purpose crops is to remove stock prior to stem elongation, so they do not remove the reproductive heads,” Shawn said.

“Producers should also be mindful of residual biomass – so think about allowing crops to recover post-grazing to meet target yields.”

CSIRO is currently in the process of developing a practical system to measure this optimal level of biomass.

More information

Pinares-Patiño, C.S. McDonald, S.E. Kirkegaard, J.A. Simpson R.J. and Moore A.D. (2017) Influence of integration of dual-purpose wheat and canola crops in a pasture system on liveweight of Merino sheep, ASAP Conference, Adelaide 2016