Document Type : Research Paper
Authors
1
Research Department of Soil Chemistry and Physics and Fertilizer Technology, Soil and Water Research Institute (SWRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
2
. Research Department of Soil Chemistry and Physics and Fertilizer Technology, Soil and Water Research Institute (SWRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
3
Department of soil and water, Kermanshah Agricultural and Natural Resources Research and Education Center; Agricultural, research, Education and Extension Organization; Kermanshah; Iran.
4
Department of soil and water, Razavi Khorasan Agricultural and Natural Resources Research and Education Center; Agricultural, research, Education and Extension Organization; Mashhad; Iran
5
Department of soil and water, East Azerbaijan Agricultural and Natural Resources Research and Education Center; Agricultural, research, Education and Extension Organization; Tabriz; Iran
6
Department of soil and water, Isfahan Agricultural and Natural Resources Research and Education Center; Agricultural, research, Education and Extension Organization; Isfahan; Iran
Abstract
The production of compost from biodegradable urban waste is one method of waste management. This research aimed to evaluate the quality of composts in the country. For this purpose, samples were collected from compost produced in factories in Mashhad, Kermanshah, Tehran (first and second grade from Khahrizak), Tabriz, and Isfahan (Isfahan, Shahin Shahr, Lenjan, and Najafabad) over a period of two years. The samples were analyzed for nitrogen, phosphorus, potassium, total lead, total nickel, total chromium, total cadmium, total arsenic, total cobalt, foreign materials, moisture, electrical conductivity, and acidity. The results showed that none of the composts produced in the country met the standard conditions and failed to comply with the Iranian national standards in at least one or more parameters. The average concentrations of cadmium, lead, nickel, chromium, cobalt, and arsenic in the samples were 3.27, 134, 69, 76, 7.90, and 3 mg/kg of dry weight, indicating non-compliance rates of 6.5%, 16%, 11.2%, 9.47%, 0.59%, and 0%, respectively. The pH had an average of 7.32, showing a 13.4% non-compliance with standards. Electrical conductivity (EC), organic carbon (OC), carbon-to-nitrogen ratio (C:N), nitrogen (N), phosphorus (P2O5), potassium (K2O), and moisture content averaged 5.71, 20.7, 12.7, 1.81, 1.01, 0.96, and 23.6%, respectively, indicating non-compliance rates of 10.7%, 80.5%, 68%, 36.4%, 96.7%, 0%, and 31.4% compared to first-grade compost. Therefore, for agricultural use, it is necessary to evaluate and improve the quality of produced composts concerning organic carbon content and heavy metals, especially lead, to address the non-compliance issues.
Keywords
Main Subjects
)