Soil Phosphorus
Benchmark Value
Scoring Curve
This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.
Evidence & Context
The benchmark representing the highest ecological condition, capable of supporting P-sensitive keystone species like Themeda triandra, is a range of 2–6 mg/kg for available phosphorus (measured as Colwell-P or Olsen-P).
Available phosphorus (Olsen-P or Colwell-P) in soil
This benchmark defines the range of available soil phosphorus that supports the highest ecological condition in temperate grassy woodlands and plains, enabling sensitive native species to thrive.
Derived from measurements in unfertilised native forests and defined botanical stability thresholds for high-quality native grasslands.
Supporting Sources (19)
Additional references from the underlying research that informed this benchmark.
(PDF) Phosphorus accumulation and other changes in soil ..., accessed August 11, 2025
View SourceA new detailed map of total phosphorus stocks in Australian soil
View SourceRoot Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits
View SourceThe phosphorus and nitrogen requirements of temperate pasture species and their influence on grassland botanical composition - CSIRO Publishing, accessed August 5, 2025,
View SourceBusted: The I-hate-phosphorus myth - AusBonsai, accessed August 11, 2025
View Source(PDF) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 4, 2025,
View SourceOld field restoration improves biodiversity and soils and large parts of Australia have huge potential to be remediated, accessed August 11, 2025
View SourcePhosphorus - Tas | Fact Sheets | soilquality.org.au
View SourcePhosphorus fertiliser management for pastures ... - CSIRO Publishing
View SourceAustralian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC
View SourceNitrogen and Phosphorus Retranslocation of Leaves and Stemwood in a Mature Eucalyptus Forest Exposed to 5 Years of Elevated CO2 - Frontiers, accessed July 19, 2025,
View SourceRestoring ecological function in temperate grassy woodlands: Manipulating soil nutrients, exotic annuals and native perennial grasses through carbon supplements and spring burns - the UWA Profiles and Research Repository, accessed August 11, 2025
View SourceUnderstanding soil tests for pastures | Soil | Farm management ..., accessed May 15, 2025,
View SourceUnderstanding soil tests for pastures | Soil | Farm management ..., accessed July 17, 2025,
View Source(PDF) Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate
View SourceThe changing the availability of nutrients in global grasslands ..., accessed August 28, 2025,
View SourceThe role of regenerative agriculture in sustainable land use - ClimateWorks Australia
View SourceToo much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics
View Source(PDF) Individual plant species responses to phosphorus and ...
View Source