نوع مقاله : علمی - پژوهشی
نویسندگان
1 بخش تحقیقات جنگل، مؤسسه تحقیقات جنگلها و مراتع کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران.
2 بخش تحقیقات منابع طبیعی، مرکز تحقیقات کشاورزی و منابع طبیعی استان هرمزگان، سازمان تحقیقات، آموزش و ترویج کشاورزی، بندرعباس، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: The natural forests of southern Iran are one of God's gifts that were adapted to the fragile natural environment of southern Iran millions of years ago. The quality and health of the soil is one of the important factors in the sustainability of the forest ecosystem. The presence of different species can affect the physical, chemical, and biological properties of a habitat's soil, ultimately increasing or decreasing the production and quality of forest ecosystems.Also, identifying the elements that make up the forest, including the canopy and its role in the preservation and survival of the forest, is the most fundamental way to optimally manage forests, because nutrients and soil microbial activities accumulate under the canopy, especially in arid and semi-arid ecosystems, and these effects are also related to the size and extent of the canopy and cause changes in the physical, chemical, and biological properties of the soil. So far, no study has been conducted to investigate the various soil characteristics under and outside the canopy of the Moringa peregrina and Salvadora persica species, as well as to determine the soil quality index of these two native and valuable species in their habitats in the Sahara-Sindhi forests. Therefore, this study attempted to create a general and comprehensive view of the effects of different forest species on ecosystems and their optimal management for managers and planners by better understanding the impact of these species on the soil and the causes of changes in the soil of their habitats.
Methodology: For this study, two sample plots with an area of one hectare (100 × 100 m) were selected in the habitats of (Moringa peregrina (Forssk.) Fiori) in Bashagerd and (Salvadora persica L.) in Bandar Abbas. In Bashagerd, 15 trees were randomly selected from among the M. peregrina trees. Soil sampling was carried out from a depth of zero to 15 cm under the canopy of the trees (in the distance between the middle of the trunk and the end edge of the canopy) and outside the canopy (control) (in a place where there is no plant) in the east direction of the trees. To obtain a composite soil sample from under and outside the canopy of the M. peregrina trees, soil samples taken from under and outside the canopy of all three trees (randomly) were mixed well together and converted into a composite sample, so that finally five composite soil samples from under the canopy and five composite soil samples from outside the canopy of the M. peregrina trees were obtained. In Bandar Abbas, 15 trees were randomly selected from among the S. persica trees, and soil sampling was repeated under and outside the S. persica canopy, as in the previous habitat, so that five composite soil samples were obtained from under the canopy and five composite soil samples from outside the canopy of the S. persica trees. Soil samples were passed through a 2 mm sieve and divided into two parts. One part was kept at -20°C for measuring soil microbial activity and the other part was air-dried and kept at ambient temperature for measuring soil physical and chemical properties. The physical, chemical and biological properties of the collected samples were measured using standard methods. Then, the normality of the variables was confirmed by the Shapiro-Wilk test and the positions under and outside the canopy of the normal data of the two species of M.peregrina and S. persica were compared with the independent T-test and the non-normal data were compared with the non-parametric Mann-Whitney U test. Finally, the soil quality index was obtained from the evaluation of all measured properties and analyzed as above.
Results: The results of this study showed that under the canopy than outside the canopy of M.peregrina, the values of electrical conductivity (2.11 dS/m), organic carbon (0.89%), total nitrogen (0.089%), absorbable phosphorus (12.94 mg/kg), absorbable calcium (347.89 mg/kg), absorbable magnesium (33.04 mg/kg), and nitrification potential (97.07 µg N.gˉ¹dm.5hˉ¹) were significantly different, while outside the canopy than under the canopy of M. peregrina, pH (7.92) was significantly different. Under the canopy of M. peregrina and S. persica, compared to the outside of their canopy the amounts of available potassium (843.09 and 289.64 mg/kg), available manganese (5.7 and 4.06 mg/kg), and basal respiration (1.73 and 0.74 mg CO2.gˉ¹ dm.24 hˉ¹) were significantly different, respectively. Also, the amount of microbially substrate-induced respiration under the canopy of M. peregrina (11.44) and outside the canopy of S. persica (6.62) (mg CO2.100 gˉ¹ dm.hˉ¹) were significantly different. The soil quality index (7) showed a significant difference only under the canopy of M. peregrina in Bashagerd.
Conclusion: Based on the findings of this study, both species caused changes in the physical, chemical, and biological properties of the soil in their habitats, as well as the soil quality index. These findings emphasize that the dominant species of each habitat are a reflection of the complex interaction of biotic and abiotic factors, and that soil, as one of the most important environmental factors, plays a key role in the development and sustainability of vegetation cover. Therefore, given the importance of continuous soil monitoring, observing changes in soil properties in different time intervals and conducting periodic studies can provide a more accurate assessment of the change process and provide reliable information for the scientific management and conservation of Sahara-Sindhi forests.
کلیدواژهها [English]
)