Soil Potassium
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 2 benchmarks together — the LowerThreshold form drives the primary score, while 1 guard(s) constrain the result.
Contributing Benchmarks
Evidence & Context
This threshold is quantitatively defined by the upper boundary of the "Low" category in the Agriculture Victoria soil test interpretation guidelines, which are calibrated against observed plant deficiency symptoms and production losses.
Lower critical threshold concentration of plant-available potassium in soil below which ecosystem health and productivity are compromised.
The lower critical threshold for soil potassium in Sandy Loams soil texture represents the concentration below which forest ecosystem health, resilience, and productivity are significantly compromised.
Potassium deficiency impairs fundamental processes such as photosynthesis, water-use efficiency, and disease resistance in all higher plants, including eucalypts and other woodland species.
Sources (1)
Understanding soil tests for pastures
View SourceSupporting Sources (21)
Additional references from the underlying research that informed this benchmark.
Nutrient Disorders in - Plantation Eucalypts - Murdoch Research Portal, accessed August 9, 2025
View Source
NSW State forest estate - Forestry Corporation, accessed August 9, 2025
View SourceRoot Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits
View SourceDetermining reference conditions for management and restoration of temperate grassy woodlands: Relationships among trees, topsoils and understorey flora in little-grazed remnants - the UWA Profiles and Research Repository, accessed August 9, 2025
View SourceEnvironmental factors affecting plant growth | OSU Extension Service, accessed August 9, 2025
View Source
Forest Health - Sustainable Timber Tasmania, accessed August 9, 2025
View SourceTowards restoration of grassy White and Yellow Box woodlands ..., accessed August 9, 2025
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Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - CSIRO PUBLISHING | Crop and Pasture Science, accessed July 24, 2025
View Source
Plans + Policies - Sustainable Timber Tasmania, accessed August 9, 2025
View SourceSoil fertility in grazing systems: Manage potassium to manage nitrogen - Crops and Soils, accessed July 28, 2025,
View SourcePotassium - Tas | Fact Sheets | soilquality.org.au, accessed May 11, 2025,
View SourceSoil condition | NSW State of the Environment, accessed July 28, 2025,
View SourcePotassium and sulphur - emerging deficiencies in the southern region - GRDC
View SourceRegenerative Agriculture - Nuffield Farming Scholarships
View SourceA review of plantations as a water intercepting land use in South Australia, accessed August 9, 2025
View SourceAustralian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 9, 2025
View SourcePotassium management in crops - Soil fertility - Government of Alberta, accessed August 9, 2025
View Source
Queensland Acid Sulfate Soil Technical Manual, accessed August 9, 2025
View SourceApproved Conservation Advice for the White Box - Yellow Box - Blakely's Red Gum Grassy Woodland and Derived Native Grassland - DCCEEW, accessed August 6, 2025
View SourceUnderstanding soil tests for pastures | Soil | Farm management - Agriculture Victoria, accessed August 9, 2025
View Source
Mean concentrations of soluble and exchangeable cations in ..., accessed August 9, 2025
View Source