Incorporating dual-purpose crops in your pasture feedbase system
15 July 2016
CSIRO researcher Dr Cesar Pinares-Patino presents part two of his findings from an MLA-funded, interlinked research project which is looking at grazing dual-purpose wheat and canola. The goal is to increase sheepmeat production while reducing business risk in the high rainfall zone.
- Inclusion of dual-purpose wheat and canola in a grazing system reduces the autumn/winter feed gap during poor growing seasons
- In good growing seasons, benefits from dual-purpose crops (DPC) come from higher grain production
- The proportion of the ‘farm’ devoted to DPC (one-third) in the experiment now seems too high, because it is placing pressure on pasture availability/composition
- The optimum proportion of farm area devoted to DPC needs further research, but probably should be no higher than about 15–20%, given present knowledge
- Lack of rain post-sowing is the major risk when establishing DPC.
The facts on DPCs are well established - they can fill the winter feed gap and hence reduce supplementary feeding, with little penalty in grain yield and at the same time spell pastures for later grazing.
What is unknown, and being explored by the MLA funded research, is what is the optimal area to be sown to DPCs.
“The introduction of DPC into a pasture-only livestock system will reduce the area of pasture available for grazing, producing changes in the livestock carrying capacity of the whole farm," Dr Cesar Pinares-Patino said.
These changes have been previously studied using experimental modelling (a study funded by GRDC) and more recently measured directly in MLA-funded experiments using a fixed stocking rate at Canberra.
The four-year system study at Canberra is being conducted with breeding Merino ewes and their weaners.
“Dual-purpose canola and wheat in the system that incorporates cropping are contained in one-third of the total farm area,” Cesar said.
“The rotation is canola – wheat – first-year pasture – second-year pasture – canola, and so on.
“The plots devoted to DPC cropping and permanent pastures are fixed from year to year and the stocking rate in summer is 8.7 sheep/ha (4.35 ewes + 4.35 weaners per ha of total area).”
Impact on pastures
The experiment has confirmed previous findings from GRDC-funded research that there are clear advantages (e.g. filling winter feed gap, improved animal performance and higher gross returns) from having the extra feed and grain production that is provided by inclusion of DPC in the grazing system.
However, the experiment is also indicating there is an optimal amount of crop within a DPC-pasture farming system.
“Over the first three and half years of the study, pasture condition in the pasture-only system has been maintained, whereas pasture condition in the DPC system has deteriorated,” Cesar said.
“There is now low pasture cover and increased presence of weed species, with animals requiring more supplementary feeding during summer and autumn than animals in control treatment.
“These findings indicate the proportion of land devoted to the DPC in the experiment is higher than the optimum for this particular system because it is affecting the sustainable productivity of pastures.
“More research is needed, but given present knowledge, the optimum proportion of farm area devoted to DPC cropping should probably be no higher than about 15–20%.”
Cesar said the proportion of the farm devoted to DPC crops and the number of livestock that can be supported during summer – the most critical period of the year – are the two main management decisions determining the potential benefits and risks of incorporating DPC in the system.
Read Cesar's earlier report on maximising the benefits of DPCs for ewes.
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