This project is evaluating whether the benefits of nitrogen fixation by legume crops can be amplified in a subsequent wheat crop by using added organic amendments (eg. compost) or manure. It also looks at whether the application of manures can buffer the farm business from costs associated with high synthetic fertiliser inputs.

• This trial is part of a project looking at the legacy effects of organic amendments and manure compared to inorganic fertilisers on cereal and oilseed production following a pulse crop. This is the first year at this trial site, with effects to be assessed over the next two growing seasons.
• Wheat yield following faba beans was high at this site, averaging over 9t/ha, demonstrating how legacy nitrogen from
a previous pulse crop can contribute to yield and help buffer against high synthetic fertiliser inputs
• The lowest average yield at this site was recorded in the fallow treatment with farm standard nitrogen (7.93 t/ha), while the highest yield was observed in the 10t/ha manure treatment with extra nitrogen (9.68 t/ha). This shows the potential for increased yield when nitrogen (and other nutrient) supply is matched to demand under high yielding seasonal conditions
• When wheat yields were averaged across manure treatments, the application of an extra 75kg/ha of nitrogen in-season significantly improved yield when compared to the farm standard, indicating the farm standard rate was not either enough to realise potential yield or supply did not match plant demand from stem elongation onwards this season
• When yields were averaged across nitrogen treatments, the 10t/ha manure treatment was the only manure treatment to significantly improve yield when compared to the untreated control
• When averaged across all treatments, grain protein increased from 10% to 11.2% when an extra 75kg of nitrogen was applied at stem-elongation, lifting quality from ASW to APW
• Slashing at flowering and removal of faba bean biomass reduced the yield benefit to the following crop.