Author(s): Ahmad, M.N., P. Büker, S. Khalid, L. Van Den Berg,H.U. Shah, A. Wahid, L. Emberson, S.A. Power, M. Ashmore

Year: 2013

In: Environmental Pollution 174, 244-249.

DOI: 10.1016/j.envpol.2012.11.029

Type: Journal article



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Effects of ozone on crops in north-west Pakistan

This article describes the visible signs of ozone injury to onion, cotton and potato crops found in north-west Pakistan, at ozone levels that have been modelled to occur widely across south Asia.

Although ozone is well-documented to reduce crop yields in the densely populated Indo-Gangetic Plain, there is little knowledge of its effects in other parts of south Asia. The authors surveyed crops close to the city of Peshawar, in north-west Pakistan, for visible injury, linking this to passive measurements of ozone concentrations. Foliar injury was found on potato, onion and cotton when mean monthly ozone concentrations exceeded 45 ppb.

The symptoms on onion were reproduced in ozone fumigation experiments, which also showed that daytime ozone concentrations of 60 ppb significantly reduce the growth of a major Pakistani onion variety. Aphid infestation on spinach was also reduced at these elevated ozone concentrations.

The ozone concentrations measured in April–May in Peshawar, and used in the fumigation experiment, are comparable to those that have been modelled to occur over many parts of south Asia, where ozone may be a significant threat to sensitive crops.

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