Soil fumigation with methyl bromide: the phytotoxicity of inorganic bromide to carnation plants

Abstract

SUMMARYRooted carnation cuttings often developed phytotoxic symptoms when planted in soil previously fumigated with methyl bromide, and many died. Those which recovered suffered a marked check in growth and flower production was reduced. Plant injury and effects on flower yield were more severe at high rates of fumigant application, but were reduced by flooding the soil with water or by incorporating peat into the growing medium.Plant survival and flower yield were inversely related to the concentration in soil of inorganic bromide formed by the breakdown of the fumigant. Injury to plants occasionally occurred in the presence of soil concentrations of inorganic bromide as low as 5 pglg. Flooding the soil or incorporating peat into it were beneficial because these treatments reduced the soil concentration of inorganic bromide.Carnation plants which were grown in soil previously fumigated with methyl bromide or supplemented directly with potassium bromide accumulated bromide in their leaves, and a bromide gradient was eventually established, the concentrations decreasing from the bottom to the top of the plants.The evidence that inorganic bromide is the cause of the injury to carnations is discussed, and the role of peat in alleviating the incidence and seventy of the injury is considered.