نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم و مهندسی خاک،دانشکده کشاورزی، دانشگاه زنجان، زنجان،ایران.
2 گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه زنجان، زنجان، ایران.
3 گروه مرتع و آبخیزداری، دانشکده منابع طبیعی، دانشگاه کردستان، سنندج، ایران. عضو گروه پژوهشی مطالعات محیطی دریاچه زریبار، پژوهشکده
4 بخش تحقیقات جنگل، مرتع و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان گیلان، سازمان تحقیقات، آموزش و ترویج کشاورزی،
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
This study was conducted to investigate the effects of land-use change and soil depth variations on the biological, chemical, and physical properties of soil in Fuman region, Gilan Province. Accordingly, 15 soil samples were collected from each of the natural forest, tea plantation, and paddy field land uses at five soil depths (0–20, 20–40, 40–60, 60–80, and 80–100 cm). The measured indicators included soil organic carbon (SOC), microbial respiration (Cmin), microbial biomass carbon (MBC), glomalin, mean weight diameter of aggregates (MWD), activities of dehydrogenase, acid and alkaline phosphatases, cellulase, soil pH, and the metabolic quotient (qCO₂). Analysis of variance showed that the interaction effect of depth and land use on all measured indicators was significant at the 1% probability level (p < 0.01). Overall, the tea plantation performed better in most indicators compared with the other two land uses; in the surface layer (0–20 cm), the values of SOC, Cmin, MBC, cellulase, glomalin and MWD were respectively 17.94%, 0.36%, 19.44%, 16%, 14.3% and 7% higher relative to the forest, and 36.86%, 1.68%, 46.79%, 23.61%, 55.92% and 52.34% higher relative to the paddy field. In the surface soil layer, acid phosphatase activity in the forest land use was 23.66% and 10.88% higher than those in the tea plantation and paddy field, respectively. In contrast, in the surface layer, Dehydrogenase and alkaline phosphatase activities, and qCO₂ in the paddy field were, respectively, four times, 7.35% and 31.86% higher relative to the forest, and 15.89%, 9.5% and 43.28% higher relative to the tea plantation. This increase suggests that under flooded paddy field conditions, soil microorganisms require greater energy expenditure to maintain their metabolism as a result of oxygen limitation and low carbon-use efficiency. Other indicators also showed a significant decrease with increasing depth. These results indicate the relative superiority of tea plantations in terms of biological quality and structural stability of the soil compared with other land uses, and highlight the importance of maintaining this land use for the sustainability of soil ecosystems in northern Iran.
کلیدواژهها [English]
Land-use change is one of the key factors affecting soil quality and sustainability. Such changes can alter the biological, chemical, and physical processes of soils and significantly influence the storage and dynamics of soil organic carbon (SOC). Among different land uses, tea plantations—with their permanent vegetation cover and minimal tillage can enhance soil properties, while paddy fields, due to flooded conditions and fluctuating redox potential, may cause a decline in soil biological quality. This study aimed to investigate the effects of land-use change from natural forest to tea plantation and paddy field on the biological, chemical, and physical properties of soil in Fuman region, Gilan Province, northern Iran.
Soil sampling was conducted from three land uses—natural forest, tea plantation, and paddy field at five depths (0–20, 20–40, 40–60, 60–80, and 80–100 cm). The measured indicators included soil organic carbon (SOC), microbial biomass carbon (MBC), microbial respiration (Cmin), glomalin, mean weight diameter of aggregates (MWD), the activities of dehydrogenase, acid and alkaline phosphatases, and cellulase, soil pH, and the microbial metabolic quotient (qCO₂). The experiments were performed in a factorial arrangement based on a completely randomized design with three replications. Data were analyzed using SAS and Excel software, employing two-way analysis of variance (ANOVA) and Duncan’s multiple range test to compare means..
The results showed that the interaction effect of land use and soil depth on all measured indicators was significant at the 1% probability level (p < 0.01). Overall, the tea plantation demonstrated superior performance in most indicators compared with forest and paddy land. In the surface layer (0–20 cm), SOC, MBC, and glomalin were 17.94%, 19.44%, and 14.3% higher than in the forest, and 36.86%, 46.79%, and 55.92% higher than in the paddy field, respectively. Conversely, dehydrogenase activity and qCO₂ in the paddy field were four times and 31.86% higher than in the forest, and 15.89% and 43.28% higher than in the tea plantation, respectively, indicating lower microbial efficiency under anaerobic conditions. Furthermore, MWD and glomalin exhibited the highest values in the tea plantation and decreased significantly with depth.
The findings revealed that tea plantations, due to their continuous root systems and minimal disturbance, improved the physical, chemical, and biological quality of soil and exhibited greater stability compared with forest and paddy land. In contrast, flooded conditions and mechanical disturbance in paddy soils reduced microbial activity and metabolic efficiency. Therefore, maintaining and expanding tea plantation land use, along with appropriate organic matter and nutrient management, can play an important role in enhancing soil health and sustaining the soil ecosystems of northern Iran.
This article was conducted with the financial and moral support of the Vice Chancellor for Research, University of Zanjan.
Financial support for this research was provided by the University of Zanjan, Faculty of Agriculture in the form of a student thesis research of the first author and Done for the second author.
Conceptualization A.G.; methodology, A.T. and A.G.; software, A.T. and P.K.; validation, A.T., A.G.; formal analysis, A.T.; investigation, A.T.; resources, A.T and A.G.. data curation, A.T., and SH.S.Z; writing—original draft preparation, A.T.; writing—review and editing, A.T. and A.G.; visualization, A.T and A.G.; supervision,A.G.; project administration, A.G.; funding acquisition, A.T. and A.G. All authors have read and agreed to the published version of the manuscript.
Generative AI and AI-assisted technologies were not used in writing this article.
The data of this study are available upon request from the corresponding author.
We would like to thank the University of Zanjan for providing the necessary facilities to conduct this research.
The respected reviewers are thanked for providing structural and scientific comments.
The authors have observed ethical principles in conducting and publishing this scientific research, and this is confirmed by all of them.
The authors declare no conflict of interest.