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Potassium fixation of some calcareous soils after short term extraction with different solutions
- Najafi-Ghiri, Mahdi, Rezabigi, Soodabeh, Hosseini, Sara, Boostani, Hamid Reza, Owliaie, Hamid Reza
- Archiv für Acker- und Pflanzenbau und Bodenkunde 2019 v.65 no.7 pp. 897-910
- Mollisols, Vertisols, calcareous soils, calcium, calcium chloride, carbonates, citrates, citric acid, hydrochloric acid, illite, magnesium, palygorskite, potassium, potassium fertilizers, smectite, Iran
- This investigation was done to determine the release of potassium (K) from five calcareous soils of southern Iran using 0.025 M CaCl₂, HCl and citric acid during six successive extractions and to study the K fixation capacity of the soils after K release experiment. Mineralogical study indicated that Vertisols and Mollisols were dominated with smectites; while other soils had illite, chlorite, palygorskite and smectite. Results indicated that citric acid extracted more K than CaCl₂ and HCl (137 vs. 111 and 113 mg kg⁻¹, respectively). The analysis of calcium (Ca), magnesium (Mg) and K concentrations in the solutions suggests that the exchange of K with soluble Ca and Mg (originated from dissolution of carbonates by acidic solutions) is the main mechanism of K release, but citrate is able to dissolve K-bearing minerals and release K in slightly calcareous soils. Soils with more illite released more K. Potassium fixation capacity of soils increased after extractions of soils with different extractants from 324 to 471 mg kg⁻¹, with no significant difference. It is suggested to apply more K fertilizers in K-depleted calcareous soils and use of different solutions for extracting K from soil minerals may be a temporary and short term solution.