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.
Evidence & Context
Proposed Lower Critical Threshold (Colwell-P, mg/kg): 5-10 mg/kg
soil phosphorus refers primarily to plant-available phosphorus fractions, with a focus on measurements obtained via the Colwell-P test (expressed in mg/kg)
This benchmark represents the lower critical threshold of plant-available soil phosphorus (Colwell-P) below which soil health and crop productivity are significantly compromised in tropical monsoonal savannas under agricultural crop production.
Below this range, it is anticipated that even P-efficient crops and a healthy soil biology would struggle to maintain adequate productivity and support robust ecosystem services without significant yield penalties and potential degradation of soil health over time.
Sources (1)
Soil phosphorus–crop response calibration relationships and criteria for winter cereal crops grown in Australia - CSIRO Publishing
View SourceSupporting Sources (3)
Additional references from the underlying research that informed this benchmark.
Based on levels indicating severe P deficiency for plant growth and likely impairment of soil ecological functions (e.g., microbial activity, nutrient cycling), drawing from S18, S43, S44, S50 (interpreted for cropping context).
Based on levels where P loss to the environment (leaching/runoff) becomes a significant risk, or where potential for P toxicity or nutrient imbalances may arise. Threshold is highly dependent on soil PBI, texture, and hydrology.
Derived synthesis from 1, S26, S41, S55, S56, S68, with ecological interpretation and adjustment for regenerative principles.