Abstract

Today, population growth and demand for agricultural production have resulted in the significant damage to the natural ecosystem, including forests and rangelands, and have turned them into farmlands. Territorial land use changes can result in changes in chemical and physical features of soils, which in turn, may ultimately lead to land degradation. Understanding the effects of land use changes on soil features is very important as it helps with assessing the sustainability of natural ecosystems. Therefore, in the current study, we sought to compare changes in soil physico-chemical properties, soil deterioration index (SDI), soil erodibility factor (K factor) and the soil organic carbon (SOC) stock in three types of land use, namely: protected forest (PF), natural forest (NF) with common exploitation (overgrazing and fuel wood) and cultivated land (CL) in semi-arid regions in western Iran. Soil samples were randomly collected from 0–30 cm depths (16 + 18 + 18 at each land use, respectively; 52 samples in total). The soil texture, pH, exchangeable K, available P, total N, soil organic carbon and SOC stock were measured in soil samples. The findings indicated that in general, overgrazing with the exploitation of trees in the NF and changing the NF to CL caused a significant increase in sand (by 22.3–90.5%) and bulk density (6.1–9.16%) and a significant decrease in silt (4.34–13.56%), clay (2.36–13.5%) exchangeable K (37.68–50.63%), available P (15.58–27.42%), total N (22.2–55.5%), soil organic carbon (22.3–52.4%) and SOC stock (22.87–52.3%) (P < 0.01). The outcomes of multivariate analysis (RDA) indicated that CL correlated with sand, pH and bulk density, and EF correlated with most soil properties. The outcomes of SDI were indicative of a significant reduction in quality of soil (-5.5%) under CL, compared with NF (–21.5%) and EF (0.1%). The highest value of soil erodibility factor (K factor) was observed in the CL (0.260), and the lowest was at the PF (0.214). In general, the findings of this study showed that the exploitation of trees for fuel wood with overgrazing in the NF and after transformation of the NF to the CL caused a significant deterioration in the soil properties in the semi-arid region in western Iran.

中文翻译：

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伊朗扎格罗斯森林半干旱地区森林砍伐导致的土壤特性和土壤有机碳储量变化

摘要

如今，人口增长和对农业生产的需求已严重破坏了包括森林和牧场在内的自然生态系统，并将其转变为农田。土地用途的变化会导致土壤化学和物理特征的变化，进而可能最终导致土地退化。了解土地利用变化对土壤特征的影响非常重要，因为它有助于评估自然生态系统的可持续性。因此，在本研究中，我们试图比较三种土地利用类型的土壤理化性质，土壤退化指数（SDI），土壤易蚀性因子（K因子）和土壤有机碳（SOC）的变化。 ：受保护的森林（PF），伊朗西部半干旱地区具有常见开发用途（过度放牧和薪柴）和耕地（CL）的天然森林（NF）。从0–30 cm深度（每种土地用途分别为16 + 18 + 18）随机收集土壤样品；总共52个样品）。在土壤样品中测量土壤质地，pH，可交换钾，有效磷，总氮，土壤有机碳和SOC储量。研究结果表明，总的来说，过度采伐NF中的树木并将NF更改为CL会导致沙土（增加22.3％至90.5％）和堆积密度（6.1％至9.16％）的显着增加，而淤泥的显着减少（4.34–13.56％），粘土（2.36–13.5％）可交换钾（37.68–50.63％），可用 总共52个样本）。在土壤样品中测量土壤质地，pH，可交换钾，有效磷，总氮，土壤有机碳和SOC储量。研究结果表明，总的来说，过度采伐NF中的树木并将NF更改为CL会导致沙土（增加22.3％至90.5％）和堆积密度（6.1％至9.16％）的显着增加，而淤泥的显着减少（4.34–13.56％），粘土（2.36–13.5％）可交换钾（37.68–50.63％），可用 总共52个样本）。在土壤样品中测量土壤质地，pH，可交换钾，有效磷，总氮，土壤有机碳和SOC储量。研究结果表明，总的来说，过度采伐NF中的树木并将NF更改为CL会导致沙土（增加22.3％至90.5％）和堆积密度（6.1％至9.16％）的显着增加，而淤泥的显着减少（4.34–13.56％），粘土（2.36–13.5％）可交换钾（37.68–50.63％），可用P（15.58–27.42％），总氮（22.2–55.5％），土壤有机碳（22.3–52.4％）和SOC储量（22.87–52.3％）（P <0.01）。多元分析（RDA）的结果表明，CL与沙子，pH和堆积密度相关，而EF与大多数土壤性质相关。与NF（–21.5％）和EF（0.1％）相比，CL处理的SDI结果表明土壤质量显着降低（-5.5％）。在CL（0.260）中观察到最高的土壤可蚀性因子（K因子），在PF（0.214）中观察到最低。总的来说，这项研究的结果表明，在NF过度放牧以及NF转化为CL后采伐薪木的树木在伊朗西部半干旱地区造成了土壤特性的显着恶化。