Evaluation on the Effects of Deicing Salts on Crop using Seedling Emergence Assay of Oilseed Rape (Brassica napus)

The increasing use of deicing salts has caused various environmental problems, including crop damage along the motorway where deicing salts are sprayed during winter. Deicing salts used on roads have been reported to negatively affect crops, but little information is known about their impact on crops. A seedling emergence assay was conducted to evaluate the effects of deicing salts on crops using oilseed rape (Brassica napus) as a model plant. We tested five chloride deicing salts consisting of NaCl, CaCl2, or MgCl2 and 1 non-chloride deicing salt (SM-3) at a range of concentrations (25, 50, 100, 200, and 400 mM), and untreated control. Regardless of deicing salts, they significantly delayed and reduced seedling emergence of oilseed rape with increasing salt concentration. Non-linear regression analysis of seedling emergence with a range of salt concentrations by fitting to the log-logistic model revealed that the chloride deicing salts reduced seedling emergence more than the non-chloride deicing salt SM-3. The GR50 value, the concentration causing 50% seedling emergence, of SM-3 was 47.1 mM, while those of the chloride deicing salts ranged from 30.7 mM (PC-10) to 37.5 mM (ES-1), showing approximately 10 mM difference between non-chloride and chloride deicing salts. Our findings suggest that seedling emergence assay is a useful tool to estimate the potential damage caused by deicing salts on crops.