Investigating the relationship between economic growth, agricultural expansion and chemical pollution in Iran through decoupling index analysis

Abstract The balance between the growth of the agricultural economy and the spread of pollution due to consumption of chemical inputs is one of the major challenges in agricultural sector. In this regard, the use of decoupling index to decouple the link between agricultural production and pollution caused by the consumption of chemical inputs, such as fertilizers and pesticides, is emphasized. Therefore, in the present study, the decoupling index is first calculated in relation to the emission of pollution caused by the use of chemical inputs in the process of agricultural production during the period of 1991-2016 in Iran. Then, by systematically reviewing the existing literature, the factors affecting the decoupling index in the agricultural sector of Iran are evaluated using the ARDL model. The results showed that in recent years, pollution indicators in relation to chemical inputs have not had an ideal trend and despite the further growth of agricultural production, the quality of the environment has experienced a declining trend. The results of the decoupling index related to the use of chemical pesticides and fertilizers in Iran show that during a 26-year period, only 5 and 4 years of use of these inputs have had a sustainable state compared to production growth. Also, among the factors affecting the decoupling index, the value-added variable of the agricultural sector has the most positive effect on this index and thus, increases the level of pollution in the agricultural sector in the long run. The variables of gross domestic production (GDP) and the area under cereal cultivation in the agricultural sector will also increase the decoupling index.