Understand pasture’s nutrient needs

Agronomist Matt Mahoney (right) tests soil with a client.

With global production and supply chain factors impacting domestic fertiliser prices, putting nutrients where they are needed is more important than ever.

Matt Mahoney, owner of Booralite-based Agridome Consultancy, said he regularly saw producers who knew the value of nutrients in the soil, but also grappled with how best to make decisions about nutrient spend to optimise return on investment.

“My message to clients is that the only way to really know your soil nutrient status is to test soil regularly and monitor nutrient management programs,” Mr Mahoney said.

“The more testing you do, the more accurate you'll be with your nutrient program.

“For larger paddocks where nutrient status may differ significantly due to variations in elevation or soil type, for example, it’s worthwhile testing multiples zones or areas.

“This picks up within paddock variation to more closely manage soil nutrient levels and fertiliser application for specific nutrients.”

Mr Mahoney said strategic soil testing targeting critical nutrients, such as phosphorous, could provide specific data from which recommendations could be made to ensure fertiliser went where it was needed and at the right rate.

“This helps ensure the important nutrients are monitored and managed accordingly, and you can even go to variable rate application technology if you want to go the whole distance,” he said.

“If you can modify application rates automatically across the field as opposed to a blanket application over a whole paddock, you can avoid possible oversupply of nutrients in some areas and undersupply of nutrients in others and reduce costs.

“The payback from that strategic testing can be potentially immediate, depending on the fertiliser application rates.

“Not only is it just good nutrient management, but there is also yield maximisation and the potential for savings in application rates on some areas, as well as being better for the environment.

“A sensible and sustainable nutrient management program makes sense and should maximise the return on investment by making every granule go where it is needed.

“Nutrient prices have increased like most farm inputs, but so have the value of products we’re producing on our farms.”

Iain Elgin manages his family’s 3000-head intensive sheep grazing property in Highlands and undertakes soil testing each autumn and spring.

“I farm for profit. In my mind, there is just no other way to get an understanding of fertiliser requirements than to test your soil. Anything else is just guessing,” Mr Elgin said.

“Soil testing is the method by which I understand where my soil fertility is.

“Fertiliser is what I use to increase nutrients in the soil, after sheep and growing grasses takes it out. This nutrient investment defines what’s in the soil and how much growth I get out of it.

“I rely on my agronomist to translate soil test results into actions. I expect the savings I make from not blanket spreading or the lesser amount I apply to be reflected in productivity.

“I’m making more from what I produce than what I invest.”

Incitec Pivot Fertilisers technical agronomist Lee Menhennet said farmers were increasingly interested in management tools to help improve soil health.

“Precision agriculture approaches such as grid mapping can deliver a variable rate map for varying rate spreading, allowing producers to target nutrients within a paddock, further refining application to maximise the nutrient investment,” Mr Menhennet said.