Post-fire erosion is a main concern to society because it has inflicted serious damages in managed ecosystems. In this study, the impacts of fire and time after fire events on soil erosion (as predicted using ¹³⁷Cs technique) and on some soil chemical and physical properties were investigated in steep rangelands of western Iran. Three sites in rangelands with similar slope gradients and parent materials were selected, and within each site, the burnt (1, 5, and 10 years after the fire events) and the unburnt treatments were studied and soil samples were collected from five depths (0–2.5, 2.5–5, 5–10, 10–20, and 20–40 cm) with three replicates. The results indicated that soil organic matter (SOM), total nitrogen (TN), available phosphorus (P_ava), available potassium (K_ava), electrical conductivity (EC), and bulk density (BD) were significantly different between burnt and unburnt treatments for two times (1 and 5 years) after fire events. No significant difference by Duncan’s test was obtained for these properties between the 10 and 5 years after fire events. In addition, clay and sand contents and magnetic measures (χ_lf, χ_hf) were significantly different between burnt and unburnt treatments for all the three times after fire. The results of soil erosion by the ¹³⁷Cs technique showed that profile distribution model (PDM) estimated the mean soil erosion rate of 38.9 and 23.02 Mg ha⁻¹ year⁻¹ in the three studied years in the burnt and the unburnt rangelands, respectively. Fire events increased soil erosion rate and altered soil physical, chemical, and magnetic properties in the studied steep rangelands. Overall, the results confirmed that the ¹³⁷Cs technique could be used as a rapid and efficient model to determine soil degradation in the rangelands. The fire diminished soil organic matter and, subsequently, reduced aggregate stability, and increased soil erosion and degradation in the burnt rangelands. Hence, understanding historical contexts of fire occurrences is paramount to increase our capacity for ecological transformations and management in the face of the critical situation.

火灾后的侵蚀是社会关注的主要问题，因为它对可管理的生态系统造成了严重破坏。在这项研究中，在伊朗西部的陡峭草原上，研究了火灾发生后的火灾和时间对土壤侵蚀的影响（如使用¹³⁷ Cs技术预测的）以及对土壤化学和物理性质的影响。选择坡度梯度和母体材料相似的牧场中的三个地点，并在每个地点内研究烧毁（火灾发生后1、5和10年）和未烧毁的处理方法，并从五个深度收集土壤样本（0 –2.5、2.5–5、5–10、10–20和20–40 cm），一式三份。结果表明，土壤有机质（SOM），总氮（TN），有效磷（P _ava），有效钾（K _ava）），起火后两次（1年和5年）燃烧和未燃烧处理之间的电导率（EC）和堆积密度（BD）显着不同。在火灾发生后的10到5年之间，通过这些特性的Duncan测试没有发现显着差异。另外，黏土和沙子含量和磁性措施（χ _LF，χ _HF）是火灾后，所有的三次烧和未燃烧处理之间显著不同。¹³⁷ Cs技术的土壤侵蚀结果表明，剖面分布模型（PDM）估算的平均土壤侵蚀速率为38.9和23.02 Mg ha - ¹ 年^-1在研究的三年中分别在烧过的和未烧过的牧场上。在所研究的陡峭草原上，火灾增加了土壤侵蚀速率，并改变了土壤的物理，化学和磁性。总体而言，结果证实了¹³⁷ Cs技术可以用作确定牧场中土壤退化的快速有效模型。火灾减少了土壤有机质，继而降低了集料的稳定性，并增加了被烧牧场的土壤侵蚀和退化。因此，面对紧急情况，了解火灾发生的历史背景对于提高我们的生态转型和管理能力至关重要。