نوع مقاله : علمی - پژوهشی
نویسندگان
1 سازمان تحقیقات، آموزش و ترویج کشاورزی، مؤسسه تحقیقات جنگلها و مراتع کشور، بخش تحقیقات جنگل
2 استادیار پژوهش، مؤسسه تحقیقات جنگلها و مراتع کشور، سازمان تحقیقات و آموزش کشاورزی، تهران، ایران
3 کارشناس پژوهش، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان بوشهر، سازمان تحقیقات و آموزش کشاورزی، بوشهر، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: In southern Iran, harsh climatic conditions—including high temperatures, aridity, intense evaporation, low rainfall, forest degradation, and land-use changes—make forest restoration and development critically important. Utilizing native species such as Christ’s Thorn Jujube (Ziziphus spina-christi), Iranian Mesquite (Prosopis cineraria), and Karat (Acacia nilotica), alongside effective water management techniques, can be pivotal for the success of afforestation projects. These species are naturally adapted to the region and hold significant economic, social, and environmental value. This study aimed to identify the most effective rainwater harvesting method and irrigation schedule to optimize the establishment and survival of these three tree species.
Material and Methods: The study was carried out at the Aquifer Management Research Station in Bushehr Province (Kenari Village, Tangestan County) on a 10-hectare site characterized by a hot, arid climate within the Saharo-Sindian phytogeographical zone. The experimental area comprised alluvial fan deposits with loamy gravelly soil and a naturally degraded stand of Christ’s Thorn Jujube. The terrain had a slope of less than 5% and was oriented east-west. The experiment was laid out as a randomized complete block design with a split-plot arrangement, replicated three times. Four factors were tested: rainwater harvesting method (earthen dams and contour furrows), irrigation interval (25 and 35 days), irrigation duration (two and three years), and tree species (Ziziphus spina-christi, Prosopis cineraria, and Acacia nilotica). Earthen dams and contour furrows were constructed according to surveying maps along predetermined lines. Each subplot was planted with 36 seedlings per species. Irrigation was applied from mid-April to late November according to the assigned schedules, continuing for two or three years. Maintenance operations accompanied irrigation. At the study’s conclusion, seedling survival was counted, recorded, and analyzed.
Results: The overall mean survival rates for Ziziphus spina-christi, Prosopis cineraria, and Acacia nilotica were 62.7%, 49.9%, and 27%, respectively. The differences in survival rates among the three species were statistically significant at the 5% level. Interaction effects among rainwater harvesting method, irrigation interval, and irrigation duration on survival rates were significant (α = 0.05, p = 0.009). Seedling survival was higher behind earthen dams compared to contour furrows. Survival declined over the 10-year period, with the greatest mortality occurring during the first two years. Mortality of Ziziphus spina-christi ceased after year four, while Acacia nilotica and Prosopis cineraria continued to experience mortality at a slower rate until the final year. Rainfall data indicated drought conditions during the first two and last three years of the study. Nevertheless, thanks to supplementary irrigation and rainwater harvesting, the seedlings survived, underscoring the importance of supportive measures for afforestation projects in southern Iran.
Conclusion: The findings indicate that the successful establishment and survival of Ziziphus spina-christi (Desf.), Prosopis cineraria (Druce), and Acacia nilotica (Delile) in restoration and forest development projects depend on supportive interventions such as supplementary irrigation and rainwater harvesting. Although drought occurred during the first two and last three years, these measures promoted seedling survival, resulting in survival rates of 62.8%, 49.9%, and 27% for Ziziphus spina-christi, Prosopis cineraria, and Acacia nilotica, respectively. Among irrigation schedules, watering every 25 days for three years yielded the best results. Regarding rainwater harvesting methods, earthen dams outperformed contour furrows due to superior water retention. Further research on supportive measures to enhance seedling establishment and early growth in afforestation projects is recommended.
کلیدواژهها [English]