In 2017, FWPA-supported research led to the development of the ProFert for Pine tool, which was designed to improve the capacity of softwood growers to effectively predict the success of various fertiliser options at different sites.
By combining empirical results from fertiliser experiments across Victoria, Tasmania and South Australia with growth models used by individual growers, the ProFert for Pine tool is used by softwood growers to predict response to fertiliser and, in turn, increase timber production and profitability by enabling selection of the most effective fertiliser options across these three states.
“The wider adoption and use of ProFert beyond those three initial states has been restricted due to uncertainty around its applicability in different parts of Australia, based on the results of various experiments,” according to Dr Barry May of TreeMod, who was part of the research team.
“Its applicability has, however, now been proven in southern Western Australia, thanks to this latest round of research.”
Analysing local historical datasets focused on West Australian softwood nutrition and silviculture trials revealed strong trends in the factors that determine both plantation productivity and responsiveness to fertiliser.
The limit to productivity of plantations in the relatively dry and seasonally variable environment of southern Western Australia was found to be determined largely by water availability. Water management is the key to optimising productivity in a seasonal environment, particularly in areas where water can be in short supply.
Opportunities for increased production through fertilisation rose wherever water was either in greater supply or being most efficiently used.
In order of influence, water availability, phosphorus supply and nitrogen supply had the biggest impacts on productivity and responsiveness to fertiliser.
Plantation density also had a strong influence on responsiveness to fertiliser, due to its impact on the availability of water. Advice from the research team is that wetter sites should not be over-thinned.
Another key takeaway from the research is that multiple fertiliser applications are required for optimal productivity.
“We also discovered that soil analysis can provide effective predictions of responsiveness to the application of fertiliser, and this can be used to determine whether phosphorous and/or nitrogen are required at various stages in a rotation,” said Dr John McGrath of McGrath Forestry Services, who was involved in the research.
Throughout the testing of ProFert’s applicability in this region, the research team has redeveloped ProFert to predict responses to fertiliser in Western Australian softwood plantations, taking into consideration the influence of climate and plantation density, the size and the duration of responses to nitrogen and phosphorus fertiliser in thinned plantations.
As a result, ProFert has been re-calibrated and developed to incorporate these local factors to create a version tailored specifically for southern Western Australian conditions.
The research team hopes the data collected throughout this process will have the potential to allow for a much broader look at the prediction of productivity under changing climates and different silvicultural management systems.
The project was funded by FPC, Wespine, FWPA and the Australian Government.
Dr McGrath and Dr May presented a recent webinar during which the outcomes of this work were presented in detail – view in full by clicking here.
