CSIRO senior principal research scientist, Dr Sue McIntyre, said for a long time livestock grazing had been blamed for impacting on biodiversity and the effects of fertiliser had been ignored.
“While it is true overgrazing can have serious impacts on the soil and reduce habitat quality for plants, birds and animals, the effects of fertiliser use are far more permanent,” she said.
“Because many native plants and animals are adapted to drought and low fertility soils, they fail miserably to persist when superphosphate and exotic legumes are added.”
Dr McIntyre said in her observations, native plants had fallen away quickly as fertiliser was added, and most native species had been wiped out entirely by a typical commercial spreading.
In the recent dry years, she said, fertilised pasture had been unable to cope with heavy grazing, and there had been serious implications from the loss of perennials.
It was not suggested farmers, particularly grain producers, ignore the advantages of fertilisers but they were encouraged to be aware of the effects, which could influence their management – particularly where the advantages of drought-tolerant native plants were valued.