Get soil smart

15 July 2016

For producers wanting to improve their soil productivity, there is often a significant gap between the financial investment required  to achieve the ideal nutrient levels and the soil-tested reality.

So what is the best approach to get the maximum dollar return on the annual fertiliser budget?

According to consultant, Dr Lewis Kahn, of Agricultural Information and Monitoring Services, who is presenting fertiliser workshops in NSW's New England this month, producers need to prioritise and plan and not fall to the temptation of fertilising ‘the whole farm at half the recommended rate’.

“To get the best bang for their buck, producers need to classify their farms into high, medium and low response areas on the basis of soil tests, land capability and pasture type,” he said.

“Then concentrate on investing their fertiliser budget into those high response paddocks, which will deliver the fastest and largest response and return on investment.

“Where soil fertility is below target levels, producers are far better off using their fertiliser budget to fertilise their high priority paddocks at higher rates, perhaps several times normal rates of application, to achieve the ideal range earlier.

“By improving soil fertility faster on the more responsive paddocks, more pasture is produced, enabling stocking rates to be increased which translates to higher cash flows.”

Working it out

Lewis has a good rule of thumb for working out how much extra phosphorus (P) needs to be applied to achieve the optimum Olsen P range of 15-20.

“It generally takes 9kg of P/ha to lift Olsen P by one unit so if a producer was aiming to achieve an Olsen P of 15 and their paddock was soil tested at 10, they would need to lift their Olsen P by five units, ie, apply a total of 45kg/ha of P over and above the maintenance rate,” he said.

“This capital amount of P should be split into several applications over a few years.

 “Soil testing will identify when the high priority areas meet their soil fertility targets so that producers can reduce their fertiliser applications to lower maintenance levels and focus on improving their next most responsive paddocks.

“The 5-Easy Steps booklet suggests applications will generally be in the range 0.6-1kg P/DSE.

“For example, if the stocking rate is lifted to 12DSE/ha, the annual maintenance rate would be 7-12kg P/ha.”

Lewis said producers may decide some areas of their property will not return enough on investment to warrant fertilising or they have other land management goals and they should adjust their stocking rates on those paddocks accordingly.

To learn more about fertiliser strategies, producers can attend MLA-funded Making More from Sheep and More Beef from Pastures workshops.

Event information: David Brown T: 0439 448 159 E: 


25 July – Armidale Bowling Club

26 July – Glen Innes Bowling Club


$148 per business (limit two participants)

To register visit

Tools and resources:

Visit The Five Easy Steps phosphorus tool and booklet

Visit More Beef from Pastures at

Visit Making More from Sheep at

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