Sheep and beef farmers have begun to increase their fertiliser use again. Sales increased significantly in the 2010-11 season.
Fert Research says phosphate use dropped during the previous year by about a third on the peak years between 2003 - 2005 and some farmers applied no fertiliser at all.
Technical director Dr Philip Mladenov says the increase reflects improved economic conditions on sheep and beef farms, where most phosphate fertiliser is used.
"When economic conditions are good, farmers tend to use more phosphorus fertilisers, so they reinvest in the fertility of their soils.'' he said.
''When economic conditions are not so good, the general trend is to mine phosphate from the soils and not to put on maintenance applications."
Dr Mladenov says the use of phosphorus has dipped by 25% in the last five years, from an earlier peak where farmers were using 200,000 tonnes per year.
But phosphorus sales have jumped this year.
"It looks like farmers, due to the better economic climate in the agricultural sector, have an opportunity to invest in more phosphorus at this stage and reinvigorate the soils."
In contrast, Dr Mladenov says sales of nitrogen fertiliser, used mostly on dairy farms, have levelled off.
He says that reflects more efficient use of nitrogen with the adoption of nutrient management plans.