Adding legumes into cropping sequences has proven profitable in trials at Urana with nitrogen costs much less compared to a straight cereal-canola rotation.
The NSW DPI and CSIRO improving farming system efficiency in southern NSW project is aiming at converting rainfall into more profit across a crop sequence while managing soil fertility, weeds, diseases and costs.
The project began with the first crops in 2018 and is in the final year of phase two, examining key strategies of increasing crop diversity with legume options, earlier sown systems and nitrogen fertiliser management.
Adding faba beans and chickpeas into the sequence has been trialled against a canola-wheat rotation and barley-canola-wheat.
NSW DPI research officer Matthew Dunn said the project was focused on the overall cropping system.
"Rather than focusing on the specific agronomy for the different crops in our sequence we've stepped back and looked at them over time and at the legacy effects our crops are leaving - things like soil water dynamics, soil nitrogen, pests, diseases and how does that pan out over time," he said.
Mr Dunn said performance to date the faba bean-canola-wheat sequence had proved to be the most profitable with nitrogen a major factor.
The nitrogen cost as a percentage of gross margin was analysed which showed for the faba bean-canola-wheat sequence it was only three per cent compared to 19pc for canola-wheat.
Mr Dunn said soil mineral nitrogen and moisture was tested pre-sowing and the legacy effects from the legumes was noticeable.
"In addition to increased soil mineral nitrogen following legumes a significant and consistent increase in grain yield of the following canola was observed," he said.
Along with with the reduced urea requirement the yield increased by 0.72t/ha average across 2020, 2021 and 2022 and together two increased the average annual canola gross margin by $572/ha when following a legume compared to barley.
Mr Dunn said despite three consecutive wet seasons diverse systems involving grain legumes with a lower nitrogen strategy remained more profitable, had less variable annual average gross margins and a higher return on investment than baseline cereal-canola systems.
The year the trial the varieties are the early Illabo wheat, 45Y95CL canola and Timok vetch, sown on April 21, the timely Radar wheat, Hyola Blazer TT canola and Maximus CL barley sown on May 11, and CBA Captain chickpeas and FBA Ayla faba bean also sown on May 11.
Mr Dunn said they were sown a bit later than they would have liked to due to rainfall at the start of the year.
The project also has sites in Greenethorpe and Condoblin.