Dual-purpose crops: a flexible option for Southern Tablelands sheep producers

Description

Dual-purpose crops can offer sheep producers on the Southern Tablelands of NSW a flexible and profitable option to fill the winter feed gap, according to new research.

 

A four-year study funded by Meat and Livestock Australia (MLA) has examined the benefits and risks of incorporating dual-purpose wheat and canola crops in grazing enterprises in the region.

 

Graham Centre researcher, Dr Shawn McGrath, from the Fred Morley Centre at Charles Sturt University (CSU) was part of the CSIRO-led project.

 

The research

 

The farming systems experiment was conducted near Canberra and consisted of three treatments: pasture only (control) and pasture with dual-purpose crops prioritised for grazing by either Merino ewes (ECG) or weaners (WCG).

 

Replicated farmlets were split into six paddocks of 0.23 hectare 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 findings

 

Over the four years, priority grazing of weaners on dual-purpose crops increased wool production by nine per cent or 0.4 kg greasy fleece weight (GFW) per ewe and increased average lamb production by 16 per cent or 7.6 kg live weight sold per yearling lamb, compared to a pasture-only system.

 

A key advantage of prioritising grazing for weaners was that it allowed other livestock classes to also graze the crops. In 2013, 2014 and 2016, ewes in the WCG treatment lambed down on crops, and in 2014 wethers were brought into the system to graze the wheat crops on agistment. The live weight increase by wethers was 259 kg per hectare over a 21 day grazing period.

 

Giving ewes priority access to crops reduced supplementary feeding when seasonal conditions were poor, and increased wool production by 16 per cent or 0.7 kg GFW per head compared with the control (phalaris x sub-clover based pasture).  However, sale weight of yearling lambs did not increase compared to the control.

 

Good management of crops can result in minimal impact of grazing on grain yield. In this experiment, yields for wheat were not significantly affected by grazing, however yields for canola were slightly reduced (average 17 per cent) by grazing.

 

Impact on feed supply

 

The project highlighted the change to feed supply when dual-purpose crops are incorporated into Tablelands farming systems.

 

Dual-purpose crops can supply a large amount of high quality feed during late autumn and winter. For systems that use autumn-sown crops, however, the main deficit in feed shifts to be during late summer and autumn, the period when crops are being established, so additional supplementary feeding may be required during this period. The effect of not grazing pastures over winter allows them to ‘catch-up’ by spring in comparison to systems that do not have dual-purpose crops.

 

The advantage of having two dual-purpose crops in the mix

 

Another key insight was the potential to increase the grazing window by sowing dual-purpose canola as well as a dual-purpose cereal. Canola has higher autumn growth rates, and will generally be available to graze first. However if germination or growth rates of canola are poor in a particular season, having an alternative such as dual-purpose wheat can fill the gap, so that the wheat is grazed in the sequence before canola.

 

In this project canola was grazed first in the sequence in three out of four years. Producers should be mindful that winter growth rates of canola are slower than cereals, and canola may take longer to recover from grazing. In this project the number of sheep grazing days on crops over autumn and winter ranged from 1300-3200 days per hectare.