Farm Table says:
The take home messages from this GRDC funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.
Take home messages from the paper include:
- Over the 14 trials from 2014 to 2017, the efficiency of nitrogen (N) grain recovery from soil N was ~4 times that of fertiliser N that was applied in the year of cropping.
- Maintaining high soil N levels is critical for cereal production efficiency due to the poor fertiliser N grain recovery.
- Testing of grain, stubble and soil at harvest was able to account for a mean level of ~79% of the applied fertiliser N over 23 comparisons.
- However in 4 of the 23 comparisons, testing only accounted for 30-50% applied fertiliser N.
- The majority of the additional N at harvest was recovered in the soil and averaged ~65% of the applied quantity.
- The slow and shallow fertiliser N movement in soil is likely to be impacting on grain recovery efficiency.
- Strategies to get fertiliser N deeper, more quickly, may provide useful efficiencies in uptake and reduce potential losses.
- Strategies that can improve N contribution from the legume phase will be highly productive.
- Fallow N fertiliser applications are likely to provide a benefit over at planting application in years with low in-crop rainfall.