Despite droughts and wet periods, research over an extended period has shown the positive economics of incorporating more break crops in the cropping rotation, especially legumes.
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In addition, when planting moisture is adequate, applying higher fertiliser inputs also performed well.
For mixed farmers, legume pasture phases have been highly profitable and, perhaps, underappreciated as profitable rotations.
These are part of the findings from detailed research, beginning in 2014, at two sites on the NSW Department of Primary Industries Trangie Research Centre.
Site one has a red hard-setting chromosol - strong texture contrast between surface and subsoil - containing around 20 per cent clay with pH slightly acidic and with low organic carbon.
The second site is a slightly alkaline self-mulching grey vertosol - cracking clay - with 50pc clay.
Senior author and researcher of the Trangie study, which was published in the proceedings of the Grains Research and Development Corporation (GRDC) updates recently held at Baradine and Dubbo, was NSW DPI's Jon Baird.
Others involved in the report and study include James Hagen, Queensland Department of Agriculture and Fisheries (DAF), Lindsay Bell, CSIRO, and Kathi Hertel and Branko Duric of NSW DPI.
Other sites as part of the farming systems research include Pampas, near Toowoomba, Qld, Emerald, Qld, Billa Billa, Qld, Mungindi, Spring Ridge, and Narrabri.
GRDC are major funders of the research in collaboration with DAF, NSW DPI and CSIRO.
Reports detailing outcomes at each site are available on the GRDC website.
Ley pasture - lucerne in the Trangie trials - as part of the farming systems, provided the best gross margins during the moderate and dry seasons at Trangie on both soil types.
Grain crops, post pasture phase, performed well compared to cropping only systems.
On average, the pasture systems were $696 per hectare better than the next best performing system over the dry 2017-2019 period.
Pasture phase economic advantage continued into the cropping phase from 2020 to 2022, largely because of residual fixed nitrogen and reduced risk of root and crown rot disease.
Of the five cropping only systems, the baseline rotation - typical growers practice - was wheat, wheat, barley, canola, wheat, barley, chickpea.
On the red soil, applying higher rates of fertiliser in the higher nutrient system increased cropping costs but income over the rotation improved by $540/ha.
Largely because of poorer outcomes on the grey soil in the dry years, results were poorer for high nutrient system.
Cropping systems with increased grain legume frequency for the red soil site - 50pc of crops legumes - provided gross margin increase of an additional $471/ha over the rotation period, compared to the baseline rotation.
The high legume rotation was wheat, chickpea, barley, field pea, wheat, chickpea, wheat.
Extra gross margin was a combination of factors including relatively good yields, root and crown rot disease control and residual soil nitrogen for the following cereal crops.
Largely because of higher clay content in the grey soil site, gross margins from the higher legume rotation - despite being the best of the cropping systems - was not much superior than the red soil site.
Mr Baird and colleagues emphasise that seasonal conditions for all grain regions are highly variable and improving system performance across various conditions improves long-term sustainability.
In this research, there were two distinct phases of economic returns, a drier period between 2015 and 2019, where systems averaged around $400/ha per year, largely made up of good returns from the 2016 winter crop.
In the years between 2020 and 2022, system returns increased to around $1000/ha per year.
When the ley pasture system returned to a cropping phase it produced high value crops, allowing its advantage to be maintained during the drier seasons.
The higher legume system showed greater variance in the dry and wetter seasons, with moderate gross margins during the dry phase, but once rainfall increased it accumulated the greatest system gross margin on both soil types at Trangie.
The report can be found on the GRDC website or for further details on the research, contact Jon Baird, jon.baird@dpi.nsw.gov.au.
Next week: Autumns commonly presents quandaries. Guides for future years.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
