نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری دانشکده کشاورزی دانشگاه زنجان
2 استاد دانشکده کشاورزی زنجان
3 دانشیارپژوهشی ،مؤسسه تحقیقات خاک وآب
4 استادیار پژوهشی ، مؤسسه تحقیقات خاک وآب
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
To apply sludge in agriculture, knowing its effects and transfer of heavy metals to plant is vital. For this purpose, a greenhouse experiment was conducted in the form of randomized complete block design in 2021, in the greenhouse of Soil and Water Research Institute in Karaj, Iran, to investigate the accumulation of heavy metals in forage corn grown in soil treated with different levels of sludge. The selected soil was treated with 4 different levels of urban sewage sludge at the rate of 0%, 0.5%, 2%, and 4%, with 3 replications. The results showed that, compared to the control treatment, all treatments using sludge increased wet and dry yield (P<0.05). The highest yield of shoot with an average of 214.9 gr per pot (300% increase) was obtained from the use of 4% sludge, and this treatment had a significant difference compared to the other levels of sludge (p<0.05). Compared to each other, sludge treatments did not have a significant effect on dry yield. Use of sewage sludge caused a significant increase in the concentration of Pb, Ni and Cu elements in the shoot of corn. The value of the transfer factor (TF) among the studied elements in all treatments was as follows: Cd>Cu>Pb>Ni>As>Cr>Co, where the highest average value of the TF was related to the Cd, followed by copper and Pb. Sewage sludge caused significant changes in the TF of Cd, Ni, As, Cu and Pb compared to the control. However, these changes were not significant for Cr and Co (p<0.05). The average value of root BCFroot had the following trend: Cd>Cu>Pb>Ni>As>Co>Cr. The trend for BCFshoot was as follows: Cd>Pb>Cu>Ni>As>Cr>Co. Among the investigated heavy metals, the BCF of Cd for roots and shoots, as well as its transfer factor, was higher than other heavy metals. In general, the highest concentrations for Cd, Pb and As in the shoot of the corn were 0.17, 1.94, and 0.74 mg/kg, respectively, while the permissible values of the maximum standard tolerance in livestock feed for animals raw materials from plant sources are 1, 30, and 2 mg/kg, respectively. Therefore, the increase in the concentration in the shoots was not more than the permissible limits in the national standard of Iran. However, it should be noted that the results of this investigation were only related to one-time use of the sludge sample, while the quality and contents of sludge have many variations. Considering deficiency of organic matter and phosphorus in the country's agricultural soils, the use of treated sewage sludge should be considered due to its high percentage of organic carbon and phosphorus. However, due to the changes in the quality of sludge and its multiple uses in cultivated lands, it is suggested that additional studies be conducted for different sludge in order to provide a specific agronomic recommendation based on that.
کلیدواژه‌ها [English]
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