Effect of heating on some soil properties and potassium dynamics in calcareous soils of southern Iran

Prescribed burning of plant residues in agricultural lands may increase surface soil temperature and change the dynamics of soil potassium (K). In the current investigation, the effects of two hours heating of soil to 25, 100, 225, or 350°C and cycling (one and three cycles) on properties of eight c...

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Bibliographic Details
Published in:Soil use and management 2021-07, Vol.37 (3), p.519-532
Main Authors: Najafi‐Ghiri, Mahdi, Boostani, Hamid Reza, Hou, Deyi
Format: Article
Language:English
Subjects:
Agricultural land
Burning
Calcareous soils
Calcium chloride
Combustion
Crop residues
Dynamics
Fixation
Heating
Minerals
Organic matter
organic matter combustion
Potassium
potassium fixation
potassium forms
potassium release
smectite
Soil dynamics
Soil investigations
Soil properties
Soil surfaces
Soil temperature
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Summary:Prescribed burning of plant residues in agricultural lands may increase surface soil temperature and change the dynamics of soil potassium (K). In the current investigation, the effects of two hours heating of soil to 25, 100, 225, or 350°C and cycling (one and three cycles) on properties of eight calcareous soils from southern Iran and K dynamics (K forms, release, and fixation) were studied. Results indicated that heating to 100 or 225°C had no significant effect on pH,EC, or CEC but heating to 350°C increased soil EC (from 0.53 to 0.66 dS m−1) and decreased CEC (from 25 to 19 cmol kg−1). The heating to 350°C increased all forms of K including soluble (from 36 to 84 mg kg−1, 133% increase), exchangeable (from 285 to 490 mg kg−1), non‐exchangeable (from 598 to 686 mg kg−1), and HNO3‐extractable (from 922 to 1260 mg kg−1) decreased K fixation capacity of all soils (from 351 to 235 mg kg−1). Cumulative K release from soils to 0.025 M CaCl2 ranged from 114 to 438 mg kg−1 and increased significantly after heating of soils to 350°C and reached between 233 and 783 mg kg−1. Potassium fixation capacity of fine‐textured soils (soils 2, 6, 7, and 8) after 10 times extraction with CaCl2 was increased (65%–190%). Generally, heating of soils to 350°C caused combustion of organic matter and partial destruction or collapse of K‐bearing minerals and increased release of K.
ISSN:0266-0032
1475-2743
DOI:10.1111/sum.12593