تاثیر کمپوست زباله شهری بر روند تغییرات برخی فلزات سنگین در گیاه و ارتباط آن با ویژگی‏های رشدی زعفران (.crocus sativus l)

به‌ منظور بررسی اثر کمپوست زباله شهری بر میزان تجمع عناصر سنگین (سرب، نیکل، کادمیوم و کبالت) در اندام‌های گیاهی زعفران (crocus sativus l.) و همچنین اثر کمپوست بر صفات زراعی و عملکرد، آزمایشی در قالب طرح بلوک ‏های کامل تصادفی در دانشکده کشاورزی دانشگاه بیرجند در سال‌های زراعی 1395-1394 اجرا شد. تیمار آزمایش، شامل چهار سطح کمپوست زباله شهری (0، 5، 10 و 20 تن در هکتار) با سه تکرار بود. نتایج نشان داد کمپوست زباله شهری تاثیر معنی‏داری بر غلظت سرب و کادمیوم خاک زعفران نسبت به شاهد داشت، امّا بر میزان غلظت نیکل و کبالت موثر نبود. بیشترین غلظت سرب و کادمیوم (2.85 و 1.60 میلی‌گرم بر کیلوگرم) خاک در سطح 20 تن در هکتار کمپوست زباله شهری و کمترین میزان این صفات در سطح شاهد به دست آمد. کمپوست زباله شهری سبب افزایش معنی‏دار غلظت سرب برگ نسبت به شاهد شد. بیشترین غلظت سرب برگ (0.68 میلی‌گرم بر کیلوگرم) در سطح 10 تن در هکتار کمپوست زباله شهری مشاهده شد. بر اساس نتایج، سطوح مصرفی کمپوست تاثیر معنی‏داری بر غلظت عناصر سنگین بنه و گل نداشت. همچنین نتایج بیانگر تاثیر معنی‏دار کمپوست زباله شهری بر وزن بنه دختری و عملکرد گل و کلاله زعفران بود. بیشترین میزان این صفات در سطح 10 تن در هکتار کمپوست زباله شهری به دست آمد. به‌طور کلی کمپوست زباله شهری در این آزمایش مانع از تجمع عناصر سنگین در گیاه و از این طریق سبب افزایش صفات زراعی و عملکرد زعفران شد.

effect of compost on heavy metals changing process and relationship with physiological traits of saffron (crocus sativus l.)

introduction: municipal waste compost is effective on increasing plant yield. due to the lack of organic matter in the soils of arid and semi-arid regions, the use of organic compounds such as municipal waste compost improves the physical and chemical properties and increases the fertility of the soil (khoshgoftarmanesh kalbasi, 2002). the use of municipal waste compost due to the presence of nutrients in its composition and their gradual release, which prevents the leaching and stabilization of these elements in the soil, leads to the improvement of the availability of elements for plants and direct and indirect effects on yield (ghasraldashti et al., 2014). therefore, the purpose of this project is to study the effect of different levels of municipal waste compost on the absorption of heavy metals in the soil and saffron plant, as well as its relationship with the flower and stigma performance of this valuable medicinal plant. materials and methods: municipal waste compost must be used more carefully. therefore, the effects of the application of municipal waste compost on the uptake of heavy metals (pb, ni, cd, and co) in saffron plants and their relation with arable characteristics and yield of saffron were evaluated under field conditions. treatments were four levels of municipal waste compost (0, 5, 10, and 20 t. ha-1). before planting, different amounts of municipal waste compost were mixed with the soil to a depth of 20 cm according to the experimental plan. the first irrigation was carried out at the same time as planting (7 september 2015 as a flood), and the second irrigation was done ten days after the first irrigation to facilitate the sprouting of the tubers. subsequent irrigations after the end of the flowering period were carried out according to the region’s custom at intervals of one month and in the leakage method using a siphon. this experiment was carried out based on a randomized completely block design with three replications in the research farm of the university of birjand, iran, during the cropping year 2015-2016. results and discussion: results showed that municipal waste compost improved the concentration of soil pb and cd of saffron beside control. but, municipal waste compost has not affected significantly soil ni and co. the highest concentration of soil pb and cd (2.85 and 1.60 mg.kg-1) were obtained in plants treated with 20 t. ha-1 municipal waste compost while the lowest values were recorded in the control. results showed that municipal waste compost improved the pb concentration of saffron leaf besides control. the highest concentration of leaf pb (0.68 mg.kg-1) was obtained in plants treated with 10 t. ha-1 municipal waste compost. results showed that municipal waste compost did not significantly affect the heavy metals concentration of saffron corm and flower. the average weight of cormel, flower, and stigma yield was influenced by municipal waste compost treatments. in a study by gholizadeh et al., (2018), by investigation the effect of municipal waste compost levels and maternal corm weight on vegetative and reproductive traits and photosynthetic indices of saffron plants, they found that the highest average fresh weight of flowers was obtained from the treatment of 20 t. ha-1 of urban waste compost with 5.06 g. m-2. similarly, other researchers have also reported the positive effect of municipal waste compost on the yield of dry saffron stigma (amiri, 2008). it seems that the use of municipal waste compost has increased flower yield and as a result stigma yield due to its positive effects on improving physical and chemical properties and increasing soil fertility as well as increasing the availability of nutrients by plants (khoshgoftarmanesh kalbasi, 2002; ghasraldashti et al., 2014).