تاثیر آبیاری با پساب فاضلاب تصفیه‌شده شهر پرند بر صفات رشدی و غلظت عناصر غذایی (n و p و k) در سه گیاه پوششی منظر

کاهش منابع آب با توجه به مسئله تغییر اقلیم جهانی و رشد جمعیت یکی از بحرانی‌ترین مسائل پیش‌ روی طراحان و برنامه‌ریزان توسعه فضاهای سبز در شهرها است. در برابر این چالش‌ها، نیاز فوری به بهبود کارایی مصرف آب و استفاده زنجیره‌ای از منابع آب با گزینه‌های مناسب وجود دارد. در این راستا با توجه به حجم قابل توجه پساب‌های شهری، استفاده مجدد از آنها در آبیاری فضای سبز از دیدگاه مدیریت منابع آب از نظر زیست‌محیطی و اقتصادی، اهمیت دارد. بنابراین در این پژوهش تاثیر پساب فاضلاب تصفیه‌خانه شهر پرند بر صفات رشدی و غلظت عناصر غذایی نیتروژن، فسفر و پتاسیم (n،وp و k) در سه گیاه پوششی شامل فرانکینیا (frankenia thymifolia)، فستوکاآبی (festuca glauca) و دایکوندرا (dichondra repens) در بستری با خاک لوم شنی بررسی شد. این پژوهش به‌صورت یک آزمایش فاکتوریل بر پایه طرح کاملاً تصادفی با استفاده از اختلاط آب و پساب در 4 سطح با تیمارهای آبیاری صفر (شاهد)، 50، 75 و 100 درصد نسبت به آب شیرین در 3 تکرار انجام شد. پس از سه ماه، صفات رویشی و غلظت عناصر غذایی n،وp و k در گیاهان مورد ارزیابی قرار گرفتند. نتایج بررسی تجزیه گیاه نشان داد غلظت n در گیاهان فرانکینیا و دایکوندرا در دامنه بهینه (3/5–2/5 درصد) بوده اما در گیاه فستوکاآبی غلظت n از غلظت بهینه کم‌تر بود. غلظت p در تمامی گیاهان پوششی در دامنه بهینه (0/4–0/2 درصد) به دست آمد. غلظت k در گیاهان فرانکینیا و دایکوندرا در دامنه بهینه (5–1/5 درصد) اما در گیاه فستوکاآبی از این مقدار کم‌تر بود که نشان‌دهنده کمبود این عنصر در این گیاه است. همچنین، بررسی صفات رشدی گیاهان پوششی نشان داد گیاه فرانکینیا در آبیاری با پساب کامل بهترین رشد را داشته و مناسب‌ترین گونه برای آبیاری با پساب است.

the effect of irrigation with treated sewage effluent of parand city on growth traits and concentration of nutrients (n, p and k) in three cover plants

abstractthe reduction of water resources due to the global climate change and population growth is one of the most critical issues facing the designers and planners of the development of green spaces in cities. against these challenges, there is an urgent need to improve the efficiency of water consumption and chain use of water resources with suitable options. in this regard, due to the significant volume of urban effluent its reuse in green space irrigation is important for water resource management from an ecological and economic point of view. therefore, in this research, the effect of wastewater effluent from parand city treatment plant (located in the southwest of tehran province) on the growth traits and concentration of nitrogen, phosphorus and potassium (n, p and k) in three cover plants consisting of frankenia (frankenia thymifolia), dichondra (dichondra repens) and blue fescue (festuca glauca), respectively, was studied. the study was conducted as a factorial experiment based on a completely randomized design with three replications. the wastewater at four levels of zero (control), 50, 75, and 100% was mixed with the fresh water and used for irrigation. after three months, some growth traits and the concentration of nutrients (n, p and k) in the plant were evaluated. the results of plant analysis showed that the n concentrations in the frankenia and dichondra plants were in the optimal range (2.5‒3.5%). however, the n concentrations in the shoot and root of blue fescue were less than the optimal amount. the p concentrations in all cover plants were in the optimal range (0.2‒0.4%). the k concentrations in the frankenia and dichondra plants were in the optimal level (1.5‒5%), but for the blue fescue plant, it was less than the optimum, indicating its deficiency. evaluation of the growth traits showed that frankenia plant had the best growth in irrigation with complete effluent and might be the most suitable species for irrigation with effluent.background and objective: today, treated sewage wastewater effluent is recognized as a new and permanent water resource by experts to compensate for underground water resources directly and indirectly, and treatment basically becomes meaningful when the wastewater is reused. the methods of using wastewater are extensive, including nutrition, agricultural irrigation, industries, fish farming, and green spaces. several researches have shown that the use of effluents for irrigation have had a significant effect on some characteristics of soil and plant. soleimani et al. (2023) evaluated the ecological risk and the accumulation of heavy metals in agricultural soils irrigated with treated sewage effluent, river water and well water along with chemical fertilizers. their results indicated that the low concentration of heavy metals and the presence of nutrients in the treated sewage effluent make it the most suitable water resource for irrigation because it eliminates the need of farmers for chemical fertilizers and lowers the input of heavy metals to soil. in this research, the effect of municipal wastewater effluent on the growth traits and nutrients concentration of three cover plants was studied.methods: the study was conducted as a factorial experiment based on a completely randomized design with three replications. wastewater effluent from parand city treatment plant (located in the southwest of tehran province) at four levels of zero (control), 50, 75, and 100% was mixed with the fresh water and used for irrigation of three cover plants consisting of frankenia (frankenia thymifolia), dichondra (dichondra repens) and blue fescue (festuca glauca). after three months, some growth traits and the concentration of nitrogen, phosphorus and potassium (n, p and k) in the plant were measured by kjeldahl, olsen and ammonium acetate extraction (flame photometry) methods, respectively. results: the analysis of variance showed that the n, p and k concentrations in the shoot of cover plants were significantly affected by the interaction of plant type and irrigation treatment at p < 0.05. the n concentrations in the shoot of frankenia and dichondra plants were in the optimal range (2.5‒3.5%), but it was less than the optimum in the blue fescue indicating its deficiency. the p concentrations in the shoot of all cover plants were in the optimal range (0.2‒0.4%). the k concentrations in the shoot of frankenia and dichondra plants were in the optimal range (1.5‒5%), but for the blue fescue plant, it was less than the optimum, indicating k deficiency in this plant. also, the results of the growth traits of cover plants showed that frankenia plant had the best growth in irrigation with complete effluent and might be the most suitable species for irrigation with effluent.conclusions: the finding of this study showed that irrigation with complete effluent resulted in different changes of the growth traits of cover plants. the frankenia is considered the best plant in irrigation with complete effluent, because it has performed well in all the measured growth traits. the blue fescue plant was not significantly different from the control treatment in irrigation with complete effluent, and the dichondra plant also performed poorly in irrigation with complete effluent due to the reduction of some growth traits. therefore, dichondra plant is not recommended for planting in green spaces irrigated with complete effluent.references:1. soleimani, h., mansouri, b., kiani, a., khalid omer, a., tazik, m., ebrahimzadeh, g.h., sharafi, k., 2023. ecological risk assessment and heavy metals accumulation in agriculture soils irrigated with treated wastewater effluent, river water, and well water combined with chemical fertilizers. heliyon 9(3), e14580, https://doi.org/10.1016/j.heliyon.2023.e14580.