Faculty of Natural Resources & Marine Sciences, Tarbiat Modares University, 46417-76489, Noor, Mazandaran, Iran.
J Environ Manage. 2021 May 1;285:112144. doi: 10.1016/j.jenvman.2021.112144. Epub 2021 Feb 15.
The type of vegetation cover affects the contents of organic matter and other soil features that can lead to variability of soil microbial processes, which play a key role in the nutrient cycle. This issue is especially important in mountainous semi-arid ecosystems, which have been introduced as fragile and vulnerable habitats. In the present study, labile contents of soil organic matter (SOM), microbial and enzymatic indices under the influence of forest and rangeland cover [i.e. natural forest with dominant species of Zelkova carpinifolia (Pall.) K. Koch. And three rangeland covers, converted form forest site almost 30 years ago, with dominant species of Festuca ovina L. Dactylis glomerata L. and Stachys byzantina K. Koch.] in Northern Iran have been considered including seasonal changes. The study aimed to investigate i) the effect of forest conversion to rangelands on SOM fractions, (ii) temporal dynamics of soil microbial processes and enzyme functions in different vegetation types, and (iii) determining the relationship between indices related to the content of organic matter and the size of microbial population in mountain ecosystems. Results showed that Zelkova tree type enhanced the levels of SOM contents, carbon and nutrient (nitrogen, phosphorous, potassium, calcium and magnesium) pools, and also with higher values in the summer season, the size of microbial population and processes. Additionally, the SOM turnover and microbial efficiency were almost suppressed in order to Zelkova > Festuca > Dactylis > Stachys vegetation types, respectively. Based on the obtained results, it can be concluded that the presence of tree cover in mountain ecosystems can strengthen soil function and create fertile islands. Therefore, the protection of natural forests is emphasized for the proper management and sustainability of habitats in semi-arid regions.
植被类型会影响土壤有机质和其他土壤特性的含量，从而导致土壤微生物过程的变异性，这些过程在养分循环中起着关键作用。这个问题在山区半干旱生态系统中尤为重要，这些生态系统被认为是脆弱和敏感的栖息地。在本研究中，研究了森林和牧场覆盖（即天然林，优势物种为榆属（Zelkova carpinifolia）（Pall.）K. Koch 和三种牧场覆盖，近 30 年前从森林地转换而来，优势物种为羊茅（Festuca ovina L.）、鸭茅（Dactylis glomerata L.）和欧亚香青（Stachys byzantina K. Koch.））对土壤有机质（SOM）易变含量、微生物和酶指标的影响，包括季节性变化。该研究旨在调查：（i）森林向牧场的转换对 SOM 分数的影响；（ii）不同植被类型中土壤微生物过程和酶功能的时间动态；（iii）确定与有机物质含量和微生物种群大小相关的指标在山区生态系统中的关系。结果表明，榆属树种增强了 SOM 含量、碳和养分（氮、磷、钾、钙和镁）库的水平，并且在夏季的数值更高，微生物种群和过程的规模也更大。此外，SOM 周转率和微生物效率几乎在榆属>羊茅>鸭茅>欧亚香青植被类型中受到抑制。根据获得的结果，可以得出结论，山区生态系统中树木覆盖的存在可以增强土壤功能并创造肥沃的岛屿。因此，强调保护天然林，以实现半干旱地区生境的适当管理和可持续性。
