When diagnosing road salt injury, which factor is important to consider?

• A. The soil pH only.
• B. The moisture level in the soil.
• C. The plant's location relative to where salt is applied.
• D. The plant species.

Answer: (C)

The key idea is exposure distance from where the salt was applied. Road de-icers concentrate salts near treated surfaces, so plants closest to the road or near the curb are the first and most severely affected. This proximity explains why symptoms align with the road, such as leaf burn or tip necrosis on sides of plants facing the road, and why some plants at the edge show signs while those farther away look normal.

Moisture in the soil matters because water moves salts through the soil and into roots, so wet soils can distribute salts more widely and quickly. Plant species do vary in salt tolerance, but proximity to the salt source is the main factor that determines whether injury occurs and how severe it is. Soil pH is less directly connected to the immediate diagnosis of salt injury, though it can influence nutrient uptake in general.