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Laggan Grazing Demonstration

Project: Laggan Grazing Demonstration

Producer: Shannon Arnall

Location: ‘Carinya’, Laggan

Property size: 606 ha

Soils: Quartz based, pH 4.0 (unlimed) with increasing Al to depth

Pastures: mainly native perennial grasses (weeping grass and wallaby grass) with annual grasses and subterranean clover

Enterprises: Merino breeding, mostly to Merino sires

Background: This on-farm demonstration began in January 2015. Shannon Arnall had purchased a new block of ‘native’ country that hadn’t received  fertiliser for over 13 years and was keen to increase profitability from the existing pasture in the most cost-effective way. A simple nutrient trial showed that phosphorus (P) was the major nutrient limiting pasture  growth. This was not surprising given the history of the paddock, however the question then became: does it still pay to put fertiliser out in a wool operation?

Project aim: To investigate the level of pasture and animal production that can be sustainably achieved on a native-based pasture in the Crookwell region. Specifically, the project is investigating the effect of applying fertiliser (single superphosphate) and lime  on:

  • Stocking rates and overall farm profitability (using a fully-costed economic analysis)
  • Soil fertility and pH
  • Pasture composition
  • Soil carbon levels


Paddock 1: Single superphosphate + lime – fertiliser applied annually (125 kg/ha/yr) to increase soil P over time to a targeted level and lime applied as a one-off application (2.5 t/ha) to reduce soil acidity (i.e. raise soil pH).

Paddock 2: Control – a native pasture of low fertility (i.e. the “do nothing” approach).

Paddock 3: Single superphosphate – fertiliser applied annually (125 kg/ha/yr) to increase soil P over time to a targeted level.

Results to date

The application of P at the beginning of February 2015 had an immediate impact. The two fertilised paddocks responded, growing more pasture and were able to sustain higher stocking rates (+ 28%) than the control.

While the fertilised treatments have generated higher financial returns in all years since the start of the demonstration, the differences between treatments were magnified in 2017 on the back of an exceptionally strong wool market.

As shown in Table 1, gross margins on fertilised paddocks far exceeded the control, returning between $650 and $740/ha.

Table 1: Laggan Grazing Demonstration – gross margin comparison between treatments ($/ha profit)



Matthew Lieschke
Senior Land Services Officer – Livestock
02 4824 1913 / 0428 271 127