While dual purpose crops have been utilised in mixed farming operations across WA and the East Coast for many years, there remains a requirement to promote this option to increase adoption and assist growers who are still developing their skillsets in this practice. Growers in Western Australia are also becoming more interested in the opportunities that alternative grazing crops offer away from oats and are looking to understand what options like long season wheats and grazing barleys can provide to them in their mixed farming enterprises.
Southern Dirt has successfully applied for funding through MLA’s Producer Demonstration Site (PDS) program to examine the opportunities that long season wheats as a dual purpose crop can provide to producers in their mixed farming enterprise. The PDS project will operate nine sites from 2020 through to 2023, demonstrating the suitability, practical application and benefit cost analysis of using long season wheats as dual purpose crops in the Great Southern region of Western Australia. The results and findings will be circulated through the region and the wider industry via field walks, field days, case studies and annual reports, with the aim of assisting producers in the uptake of this beneficial practice.
Dual purpose crops are planted at the break of the season, used as a feed source for livestock through the late autumn and winter period and harvested as a cash crop at the end of the season. They give growers the opportunity to address the autumn/winter feed gap through grazing with minimal or no impact to yields if ma
naged correctly. They can also be highly valuable to livestock management, by providing high quality feed in June and July and replacing supplementary feeding. They can also give new pastures time to establish, or to be rested to increase dry matter for later in the season.
To optimise grain production, removal of stock needs to occur prior to stem elongation, so as to not remove the reproductive heads, being mindful of residual biomass. This will allow crops to recover and finish post-grazing to meet target yields.
Since 2000, there has been a general increase in summer rainfall and a corresponding decrease in winter rainfall (AEGIC data 2018). Southern Dirt rainfall records show this is also the case for growers in the southern high rainfall zone of WA. As a result, crop yields are being affected, and there are larger winter feed gaps, with livestock requiring supplementary grain feeding for longer. Grazing winter crops can be the key to mixed farming profitability and is starting to gain traction through past programs such as ‘Grain and Graze’.
Winter type wheats are gaining prominence as the preferred crop as they are easier to graze than spring wheats because they remain vegetative for much longer. This means they can be grazed for longer periods of time compared to spring type wheats, with less risk of yield loss.
Table 1 demonstrates the feed benefit of grazing a winter wheat compared to an oat or barley crop. All crops were grazed at a similar stage of growth, though stocking rates were different. The long season wheat was able to provide considerably more DSE equivalent days of grazing, which would allow pastures to recover, increase in biomass and remove the need for supplementary feed. The three Producer Demonstration Sites (PDS) highlighted below, with grazed and ungrazed crops, will be harvested at the end of this season to determine if there was any impact on final yield.
Table 1: 2021 Producer demonstration sites grazing data
|Crop||Barley Serradella||Long Season wheat||Bannister Oats|
|Crop entry stage||GS.23 – GS.25||GS.22 – GS.24||GS.22 – GS,24|
|Entry date||13 August 2021||14 June 2021||12 August 2021|
|Exit date||20 August 2021||16 July 2021||21 August 2021|
|1 DSE Equivalent Days Grazing/Ha||294||640||360|
Photo 1: Ewes and lambs entering the paddock in Bridgetown on the 12thAugust 2021
Capturing the whole enterprise benefits from dual purpose crops can be difficult in a PDS. The most common methodology has been to graze the crops with lambs or ewe hoggets and measure live weight gains against those of lambs or ewe hoggets on the pasture paddock.
The results from the 2020 Kojonup demonstration site (Table 2) showed an improvement of 126.11 g/day/lamb for the lambs grazing on the Williams oats crop compared to the lambs grazing on pasture. This st
rategy captures the benefit of changes to livestock management of the operation.
Harvest data from the grazed and ungrazed crop then determines the impact of the grazing on grain production. The two are then combined to generate the net benefit (or loss) to the mixed farming enterprise (harvest results are not available from the 2020 site).
Table 2: 2020 Kojonup average daily weight gain in crop v pasture:
|Average Initial Weight (kg)||Average Final Weight (kg)||Days Grazed||Weight Gain (kg)||Daily Weight Gain (g/day)|
|Crop – Oats||39.03||43.82||14||4.79||341.95|
Photo 2: Bannister Oats after being grazed for nine days at 40 DSE stocking rate on the 21st August 2021.
While the above benefit cost analysis (BCA) is a suitable methodology for evaluating the benefits (lamb and ewe hogget weight gain) of dual purpose crops, it isn’t applicable to all producers and it may not fully capture all of the potential benefits in a mixed farming operation.
There is a trend among producers in the Great Southern and South West Western Australia who manage terminal flocks of Merino ewes joined to meat type rams such as White Suffolk or Poll Dorset producing crossbred lambs. Producers managing this type of livestock operation don’t breed their own ewes and therefore don’t carry ewe hoggets, and by producing faster growing crossbred lambs, they don’t carry any of the previous year’s lambs over winter. This ensures that all ewes within the operation can produce a lamb and they are not carrying any dry stock when the crop is being planted.
While the weight gain benefits from grazing crops with lambs or ewe hoggets over winter do not apply to this group of producers, there are still significant benefits that can be achieved through dual purpose crops by this type of livestock operation.
Dual purpose crops enable these producers to increase their cropped area, while maintaining their livestock operation by grazing crops with joined ewes. The increase in profitability is generated through grain sales by higher yields. Dual purpose crops enable producers to better capture the potential of the highly productive spring flush experienced in the southern WA regions.
Importantly, the crops should be sown as early as possible to allow grazing to begin in early winter. Crops are grazed throughout winter, enabling pastures to produce increased bulk so they are ready for the livestock when they are returned onto these paddocks in late winter to allow the crops enough time to finish and reach their full yield potential. In the event of a poor season, the extra cropping paddock/s may have to be sacrificed to livestock, however, this should alleviate the need to supplementary feed.
It is worth noting that this potential increase in cropping area through the use of dual purpose crops applies to all livestock producers, irrespective of flock structure.
The 2021 PDS in Bridgetown currently manages a livestock operation of 100% purchased Merino ewes joined to White Suffolk and Poll Dorset rams, as well as an Angus/Charolais beef production operation. One of the objectives and outcomes of the current Southern Dirt project is to understand and capture the whole of farm benefit cost analysis of increasing cropping hectares and grain production while maintaining livestock numbers. Incorporating the benefits of long season wheats into the system is expected to further improve the benefits of dual purpose crops.
The knowledge generated from this PDS will be released over the next two years as the results are compiled and generated.
The outcomes from this PDS will be transferable to all mixed farming operation within the Great Southern, South Coast and South West of Western Australia.
This Producer Demonstration Site is funded by Meat & Livestock Australia.