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Journal article
Labile potassium dependency and limited buffering capacity in highly weathered loamy and clay soils of Southwest Australia revealed by Q/I isotherms and K release
Geoderma, Vol.464, 117618
2025
Abstract
Understanding soil potassium (K) availability is critical for developing K fertilizer recommendations, especially in regions with low soil K reserves. The quantity/intensity isotherm and K release were used to evaluate the dynamics of K in loam-and clay-textured soil types developed from highly weathered parent materials in Western Australia (WA). Twenty-one soil types with a wide range of properties were collected from 0–10, 10–20 and 20–30 cm depths on farmland in WA. The equilibrium activity ratio of K+ varied from 0.1 × 10-3 to 45.6 × 10-3 (mol L-1)1/2 and was significantly higher in surface soils than subsurface soils. The labile K (KL) ranged from 0.03 to 2.18 cmolc kg−1, and the contributions of non-specifically adsorbed K towards KL were >50 % in surface soils but lesser in subsoils. The potential buffering capacity (PBCK) ranged from 5.4 to 185 cmolc kg−1 (mol L-1)-1/2 and was significantly correlated with soil effective cation exchange capacity (ECEC), pH and clay content. The ECEC alone explained 94.5 % of the variation in PBCK. The cumulative amounts of K released after 213 h ranged from 27 to 833 mg kg−1, with a rapid release of K up to 22 h followed by a gradual release until the end. In conclusion, most soils, especially surface soils, had adequate K availability for crop production but it is vulnerable to losses and depletion. Given the overall low ECEC and PBCK, split or delayed K applications are recommended, alongside practices that enhance K buffering capacity in WA soils.
Details
- Title
- Labile potassium dependency and limited buffering capacity in highly weathered loamy and clay soils of Southwest Australia revealed by Q/I isotherms and K release
- Authors/Creators
- Miaomiao Cheng - Murdoch University, Centre for Sustainable Farming SystemsRichard Bell - Murdoch University, Centre for Sustainable Farming SystemsCraig Scanlan - Murdoch University, Centre for Sustainable Farming Systems
- Publication Details
- Geoderma, Vol.464, 117618
- Publisher
- Elsevier B.V.
- Identifiers
- 991005831946907891
- Copyright
- © 2025 The Authors.
- Murdoch Affiliation
- Centre for Sustainable Farming Systems
- Language
- English
- Resource Type
- Journal article
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