Articles, Blog

NPK – improving fertiliser use efficiency


NPK Financial outlay dedicated to fertiliser applications,
is the single biggest variable expense in producing successful crops. In this emerging era of climate challenges
new thinking needs to be applied to old practices regarding more efficient use of soil nutrients
and fertilisers. Most available sources of crop nutrient management
come from older research. A 14.6 million dollar crop nutrition investment
strategy is being applied to update the understanding, and the approach. Nitrogen, phosphorus and potassium crop use
efficiency, soil storage and yield responses are all under the microscope of review… One of our key focuses for phosphorous management
is how soil type influences the response to fertiliser P. So most of our knowledge has
been developed on sandy surface soils or loamy surface soils and over the last 5 to 10 years
it’s become apparent that our current recommendation systems don’t work that well for gravelly
soils in particular the forest gravel soils. Nutrient availability is under pressure from
a variety of factors such as declining rainfall, soil amelioration and evolving crop sequencing. So all of our work, all of our field experiments
are designed so that we can use them for economic analysis so our intent is to build large data
sets that we can do economic analysis on as the project progresses and examine where the
profitable responses are. Collaboration between project lead, the University
of WA and research industry partners DPIRD, Murdoch University and CSIRO is instrumental
to plugging the knowledge gap. Soil sampling and nutrient analysis are also
key to the project. With all of our field experiments we are heavily
focussed on characterising the nutrient supply at those sites so we have a heavy focus on
soil sampling at our long term sites, we’re measuring the surface and profiles annually
to track changes over time, and we’re also measuring shoot nutrient concentration at
each site over each year as well, which allows us to monitor plant nutrient status over time
and relate plant nutrient status to soil nutrient supply. University researchers are contributing expertise
to help increase grower confidence in fertiliser application. As part of this project we have a postdoctoral
researcher fellow at University of Western Australia and and at the moment he’s working on characterising soil phosphorus forms in our soils and how that relates to soil supply to our crops. So the Laboratory work that we have at the
moment is focussing on residue decomposition. So the residue type and environmental factors
that affect residue decomposition. It’s still early in the project but updated
guidelines and decision support models are expected to be delivered towards the end of
2021 and 2022. Meanwhile growers are encouraged to apply
new thinking – with renewed confidence: nutrient supply and greater fertiliser efficiency,
nutrient distribution after soil renovation, and new in-field soil sampling methods ultimately aimed at boosting crop profitability. At the end of the day this project is really
about achieving greater profit so if we have better understanding of soil nutrient supply,
we can match our fertiliser inputs better and achieve greater profit from them.

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