Improving the profitability & sustainability of Esperance port zone grain growers

Optimising timing and rate of nitrogen applications in waterlogging conditions

Project Timelines:  February 2018 - February 2020

As cropping systems have intensified there has been an increased reliance on nitrogen (N) fertiliser, now constituting the single largest variable cost for most grain growers. The challenge for growers is supplying the right amount of N at the right time and place to meet crop demand and optimise yield and quality, without over supplying N and reducing profit.
When oxygen supply diminishes under waterlogging, N can be lost to the atmosphere largely in the form of either nitrous oxide (N2O) or di-nitrogen (N2) gas. The form of N gas is influenced by soil water content; N2 tends to be lost from highly waterlogged soil, while N2O from less saturated soil. The rate of gaseous N loss is also driven by soil carbon (C) and soil nitrate (NO3-) supply, as well as soil temperature. In high rainfall areas within the Esperance Port Zone there have been years that have been some of the worst for profitability. Growers say the decile 7+ can hurt more than anything - particularly those with large low lying flat areas that have little to no drainage systems. The alternative is that in 2017 many growers in the Esperance Port Zone regretted not putting more N on their crops and as a result they experienced low protein levels in wheat and barley.
What eventuates often is a guessing game of how much N to apply - given the associated risks of increasing financial losses with additional input costs.
This project will be coordinated by SEPWA but will be run with Summit Fertilisers, who will co-ordinate the trials and in-season crop assessments.
Three strip trials will be run in the Esperance Port Zone over two years to find some rule of thumb to be arrived at that will show the cost benefits of feeding N to canola, wheat and/or barley crops on waterlogged soils. The trial locations will be chosen in February 2018 but confirmed as the season progresses once we have a better idea of rainfall and we can then choose the best locations (based on what is waterlogged). SEPWA will also choose locations close to SEPWA Variety Trials and other trials to ensure that the N Demonstration sites are visited at field days.

For more information, please contact Aidan Sinnott at: This email address is being protected from spambots. You need JavaScript enabled to view it. or Michelle Handley at: This email address is being protected from spambots. You need JavaScript enabled to view it.
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