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.

中文翻译：

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加热对伊朗南部钙质土壤某些土壤性质和钾动态的影响

在农田中按规定燃烧植物残留物可能会增加表层土壤温度并改变土壤钾 (K) 的动态。在目前的调查中，将土壤加热两小时至 25、100、225 或 350°C 并循环（1 次和 3 次循环）对伊朗南部 8 种钙质土壤性质和 K 动力学（K 形成、释放、和固定）进行了研究。结果表明，加热到 100 或 225°C 对 pH、EC 或 CEC 没有显着影响，但加热到 350°C 会增加土壤 EC（从 0.53 到 0.66 dS m ^-1）并降低 CEC（从 25 到 19 cmol kg ^-1 )。加热到 350°C 增加了所有形式的钾，包括可溶的（从 36 到 84 mg kg ^-1，增加了 133%），可交换的（从 285 到 490 mg kg ^-1）、不可交换的（从 598 到 686 mg kg ^-1）和可提取的HNO ₃（从 922 到 1260 mg kg ^-1）降低了所有土壤的固钾能力（从 351 到 235 mg kg ^-1）。从土壤中释放到 0.025 M CaCl _{2 的}累积 K为 114 至 438 mg kg ^{-1 ，}并且在将土壤加热至 350°C 后显着增加并达到 233 至 783 mg kg ^-1。用CaCl ₂萃取10次后细质地土壤（土壤2、6、7和8）的固钾能力增加 (65%–190%)。通常，将土壤加热到 350°C 会导致有机物燃烧，以及含钾矿物的部分破坏或坍塌，以及钾的释放增加。