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.
Evidence & Context
A conservative lower critical threshold for maintaining basic ecological function and long-term productivity in cropping systems within Temperate Dry Woodlands & Native Grasslands can be proposed. This threshold would be a range, acknowledging soil type variations: For sandy soils (e.g., Tenosols, lighter Kandosols): approximately 30–50 mg/kg (Colwell K). For loamy to clayey soils (e.g., Chromosols, heavier Kandosols, some Sodosols): approximately 50–80 mg/kg (Colwell K).
Lower critical threshold for soil potassium (Colwell K, 0-10 cm)
This benchmark defines the lower critical soil potassium threshold range necessary to maintain basic ecological function and long-term productivity in cropping systems within the target biome.
This threshold is based on agronomic critical Colwell K values below which significant yield reductions occur, indicating plant stress and impaired ecological functions.
Sources (3)
Soil fertility in grazing systems: Manage potassium to manage nitrogen - Crops and Soils, accessed July 28, 2025,
View SourceUnderstanding soil tests for pastures
View SourceScanlan, C. A., et al. (2013). Soil Quality: 10 Plant Nutrition. CCMA Soil Health Knowledge Base.
View SourceSupporting Sources (2)
Additional references from the underlying research that informed this benchmark.
Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - CSIRO Publishing, accessed July 17, 2025,
View Source
Regenerative agriculture – Case studies from Western Australia, accessed May 10, 2025
View Source