نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار پژوهشی، موسسه تحقیقات جنگلها و مراتع کشور، سازمان تحقیقات، ترویج و آموزش کشاورزی، تهران، ایران. پست الکترونیک: az.salehi@rifr-ac.ir
2 استادیار پژوهشی، موسسه تحقیقات جنگلها و مراتع کشور، سازمان تحقیقات، ترویج و آموزش کشاورزی، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: Wastewater treatment plants generate substantial amounts of sewage sludge, necessitating proper management and disposal strategies. Given its potential to improve soil physico-chemical properties, sewage sludge can be repurposed as an organic fertilizer in poplar plantations, contributing to sustainable agricultural practices. However, due to its high nutrient content, particularly nitrogen and phosphorus, concerns arise regarding its potential impact on tree health, including increased susceptibility to pests and diseases. Excess nutrients may alter plant metabolism, making trees either more attractive to herbivorous pests or more resilient to infestations. To evaluate this hypothesis, a field study was conducted to assess the effects of fertilization with sewage sludge from the South Wastewater Treatment Plant of Tehran on pest and disease incidence in two poplar species (Populus nigra 62/154 and Populus alba 45/67).
Methodology: This study, as part of a broader project on the potential application of sewage sludge in poplar plantations, was conducted using a randomized complete block design (RCBD) with two factors: (1) sewage sludge at three levels (0, 10, and 20 kg/m²) and (2) species at two levels (P. nigra 62/154 and P. alba 45/67). The experiment included three blocks, each containing six plots (each 16 m²), representing a combination of sewage sludge treatment and poplar species. In total, the experiment comprised six treatments (3 sewage sludge levels × 2 species) with three replications. Each plot contained nine trees. Over four consecutive growing seasons, all poplar trees were systematically monitored for pest and disease occurrence, and data were recorded in pre-prepared forms.
Results: During the first growing season, no significant pest infestations were observed in either poplar species, and trees subjected to different sewage sludge treatments showed no differences in this regard. In the second growing season, Monosteira unicostata was identified as the primary pest, causing partial leaf fall in the middle of the growing season. The infestation rate in P. alba was nearly twice as high as in P. nigra, though no significant differences were observed among sewage sludge treatments. In the third growing season, Phloeomyzus passerinii and Chaitophorus populeti were the most prevalent pests on P. nigra, whereas Phloeomyzus passerinii and Monosteira unicostata were the dominant pests on P. alba. In the fourth growing season, water stress led to the presence of Melanophila picta on some P. nigra trees and Phloeomyzus passerinii on some P. alba trees. Across all four growing seasons, no significant differences were detected among sewage sludge treatments in terms of pest incidence.
Conclusion: The results of this study indicate that sewage sludge fertilization did not significantly influence the susceptibility of either poplar species to pests and diseases. This finding is crucial for sustainable forestry management, as it suggests that The four-year monitoring period revealed that P. alba exhibited greater resistance to economically significant pests compared to P. nigra. Future studies could further investigate the long-term effects of sewage sludge on soil microbial communities and tree physiological responses to better understand its broader ecological impacts
کلیدواژه‌ها [English]
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