نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکتری جنگل شناسی و اکولوژی جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
2 دانشیار گروه جنگل شناسی و اکولوژی جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
3 استاد ، گروه جنگلداری، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
4 استادیار ، گروه جنگل شناسی و اکولوژی جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
5 دکتری بیولوژی خاک جنگل، دانشکده علوم جنگل، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: The investigation of chemical, physical and biological soil properties in developmental stages could be an appropriate approach in low-altitude forest management concerning these ecological services. Investigating the changes in soil properties during the developmental stages of the low-altitude forest is of great importance in improving the ecological services. This research aimed to investigate the effect of different developmental stages of the mixed hornbeam stands on some physical, chemical and biological properties of soil in two seasons, autumn and summer (with a time interval of one year) in series number two of forestry plan of Shastkalateh, Gorgan.
Materials and methods: 35 half-hectare rectangular sample plots with dimensions of 50 x 100 meters were considered to identify the different developmental stages after the field visit. In each of the samples, the type of tree species, shrubs and the diameter at breast height were measured. Finally, using Feldman et al. (2018) index, three developmental stages of initial, optimal, and decay were determined for all samples and three replicates were considered for each stage. In each of these nine main sample plots of half a hectare, five micro-samples of 20 x 20 meters were selected; one of them in the centre and four others in the corners, then soil samples were taken from a depth of 0-15 cm in each micro-sample at summer and autumn. A total of 270 soil samples were analyzed.
Results: The results of this study showed that there is no significant difference in the physical properties of the soil including sand, clay, silt and bulk density in the different developmental stages in the two seasons autumn and summer. But in both seasons, the soil moisture in the optimal stage was significantly higher than in other stages. Examining the chemical and biological properties of the soil showed that electrical conductivity, organic carbon, and the ratio of carbon to nitrogen, ammonium, and nitrate of the soil had significant differences between different developmental stages in the autumn. In the summer, acidity, electrical conductivity, percentage of organic carbon, total nitrogen, and microbial biomass of carbon, ammonium, and nitrate had significant differences between different developmental stages. The results of principal component analysis using the studied variables showed that, in general, the first and second main components accounted for 39.16 and 15.11 percent of the total changes, respectively. The acidity, electrical conductivity, and percentage of organic carbon, ammonium and nitrate had a high correlation with the first axis. Soil moisture, ammonium and nitrate had a positive correlation with microbial carbon biomass. While the variables of acidity, electrical conductivity and percentage of organic carbon had a negative correlation with microbial carbon biomass. Ammonium and nitrate also had a negative correlation with acidity, and electrical conductivity and organic carbon percentage showed a positive correlation with soil moisture.
Conclusion: Based on the results of the present study, it can be stated that in the low-altitude forest of the mixed hornbeam stand, the development stages had a significant effect on the chemical and biological characteristics of the forest soil. Although in other studies the significant effect of developmental stages on the physical properties of the soil has been reported, in the present study, the developmental stages had no significant effect on the physical properties of the soil. The results of this research contain valuable information about the seasonal dynamics of the soil characteristics of the low-altitude Hyrcanian forests in different developmental stages, which shows the relationship between the forest stands and the changes in soil characteristics over time.
کلیدواژه‌ها [English]
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