Long term Phosphate Trial

The LTPE site was established in 1977 at Hamilton Victoria as a short term site to demonstrate the potential carrying capacity of improved pasture with increased phosphorus. The experiment evolved into a long term monitoring site for assessing wool quality and soil constraints such as acidification and compaction.  At the LTPE long term site at Hamilton six fertiliser rates were compared at three grazing pressures, to provide a total of 18 combinations.

Phosphorus fertiliser applications

increased sheep production and Gross Margins

Application of phosphorus fertiliser to responsive soils and pastures led to:

•    Higher pasture growth and a greater proportion of more desirable species.
•    Higher nutritive values of the forage available to stock.
•    Improved persistence of sown legumes and perennials.

This improved feedbase led to:

•    Increased stocking rates while maintaining or improving stock condition.
•    Higher reproductive performance.
•    Improved growth rates in growing stock.
•    Reduced mortality in breeding animals and lambs.

At the Hamilton Long Term Phosphate Experiment, species composition, pasture production and quality peaked at a phosphorus input rate of around 15 kg/ha (170 kg/ha single superphosphate), Olsen phosphorus level of 11 mg/kg and stocking rate 18-20 ewes/ha.  The combined effects of the improved feedbase and higher stocking rates allowed significant increases in gross margins per head and per hectare.  The comparative gross margins between low and high fertiliser input treatments were not affected by higher commodity prices, higher phosphorus fertiliser prices or higher reproductive performance rates.

Above information sourced from “Evergraze”

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