Predicting Nitrogen Cycling and Losses in Australian Cropping Systems - augmenting measurements to enhance modelling

Page last updated: Thursday, 5 October 2023 - 3:30pm

The grains industry will have access to credible information summarising nitrogen (N) cycling and losses from key grain production systems and predictions of N losses and their potential environmental impact. 

State date: 1/04/2023
Finish date: 1/07/2026 


Fertiliser inputs represent about a third of the costs production for most grain producers, dominated by N.  

The proportion of fertiliser N recovered by the crop within the season it is applied is typically small and variable and in some cases there is a poor understanding of fertiliser N not accounted for in the soil, grain and crop residues at the end of the season, which is assumed to be lost from the system. Moreover, intensively cropped soils have declining organic matter (OM) contents and many farms have negative N balances. 

Limited data and knowledge suggest growers can't rely on pulses alone to increase soil OM and N supplies, and long-term legume pastures are needed. Also, the timing and placement of fertiliser application are important. 

An increasing reliance on fertilisers to supply N to cereals and canola often results in considerable amounts of mineral N in the soil that are prone to several loss pathways with potential to impact the environment, especially in high rainfall conditions.  

This five-year project will collect a comprehensive data set of N balance and cycling with explicit measurement of loss pathways to address key gaps in data for the most important soil types and farming systems across Australia's grain growing areas. 

Extending detailed N measurements from a limited number of sites to represent the national grains industry will require the use of models. Consequently, the data collected will be also used to enhance and augment the relevant N routines in the APSIM NextGen crop and soil model. 

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Contact information

Craig Scanlan
+61 (0)8 9690 2174