Australia
February 16, 2016

By Dr Tony Hamilton (pictured), GRDC northern panellist, Forbes
 
Well-managed dual purpose crops have the potential to deliver significant returns for mixed farming operations in southern New South Wales.

Not only do they offer a quality feed source for stock when pasture supply tends to be limited in autumn and winter, but they can often be sown earlier than conventional grain-only crops and provide a disease break and additional options for weed control.

In our case we rely heavily on irrigated grazing Wedgetail wheat and grazing stubbles for our mixed livestock-cropping farming system, as it allows us to carry at least 25% more stock than would otherwise be possible.

While there are higher yielding irrigated spring wheats available, the combination of grazing value plus yield gives us a higher overall return.

The Grains Research and Development Corporation (GRDC) has supported a range of research projects over the years aimed at developing management recommendations to optimise grain yield and grazing potential.

To maximise profitability within our own operation, it’s important that we remain abreast of the research findings on dual purpose varieties, particularly when it comes to the timing and intensity of grazing which can significantly influence grain yield recovery in wheat and canola.

It’s extremely important to know the growth rate of individual varieties and closely monitor the rate of growth of each variety to ensure grazing is timely.

It is recommended that as growers, we carefully manage residual biomass at lock-up as the crop approaches stem elongation (jointing, GS30) or bolting (canola), to enhance crop regrowth and minimize the risk of yield penalties due to grazing.

Our typical program with Wedgetail wheat crops has been to pre-irrigate and apply urea pre-sowing and then sow early April at a rate of 80kg/ha plus MAP 100kg/ha. It’s important to remember that wheat streak mosaic virus can be a risk of very early sowing (such as in February/March) in some areas.

The crop will be grazed until at least Z32 which is always a compromise between lockup for yield or getting that one extra grazing - often we will take the sheep off first and then continue to graze with cattle as they don’t graze as low and we’ll have less risk of taking out the growing point.

Urea is applied after grazing - total urea requirements are determined as a result of soil tests and yield predictions but are usually in the range of 150-200 units in total. Seed is normally treated with Jockey then one or two stripe rusts sprays are applied in spring (the first at Z39).

The crop is irrigated once or twice in the spring, and occasionally three times, depending on water availability, water price and grain price.

An issue we consistently monitor and manage is the crop’s additional nitrogen requirement due to grazing. Research has shown that the nitrogen requirements of crops can more than double where growers aim to graze and achieve similar yields to ‘grain-only’ crops.

As with any crop, the key to successfully integrating dual purpose crops and capturing the benefits right across the farming system is to monitor, measure and manage according to variety, sowing time, disease, nutritional requirements, water requirements and biomass. Our experience with dual purpose wheat has been so positive that we plan to trial grazing canola in the coming years in a bid to expand our grazing options.

More information on dual purpose crops is available on the GRDC website www.grdc.com.au/uploads/documents/GRDC_Dual-PurposeCrops.pdf; www.grdc.com.au/Media-Centre/Ground-Cover/Ground-Cover-Issue-109-Mar-Apr-
2014/Northern-research-measures-dual-purpose-profitability and in recent GRDC Update papers `Grazing strategies and timing of stock removal from dual purpose cereals and canola’ www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2014/07/Grazing-strategies-and-timing-of-stock-removal-from-dual-purpose-cereals-and-canola and `optimising grain yield and grazing potential of dual purpose crops’ www.grdc.com.au/Research-and-Development/GRDC-Update-Papers/2015/08/Optimising-grain-yield-and-grazing-potential-of-dual-purpose-crops

• Dr Tony Hamilton is a farmer from Forbes, NSW, and managing director of an integrated cropping and livestock business. He is a member of GRDC’s Regional Cropping Solutions Network - Irrigation panel and a director of the Rural Industries Research and Development Corporation. He has worked as an agricultural consultant in WA and southern NSW. With a Bachelor of Agricultural Science and a PhD in agronomy, Tony advocates agricultural RD&E and evidence based agriculture.

Website: http://www.grdc.com.au

Published: February 16, 2016