The conditions that affect herbicide efficacy can also affect crop injury. For example, trifluralin can severely inhibit root growth of wheat if it is incorporated in the spring so deeply that the herbicide comes in contact with the developing root system. High herbicide application rates can also injure crops. In addition, excess moisture from heavy rainfall can cause herbicides to leach or concentrate in sufficient quantities in the crop germination zone to damage the crop. Physical and environmental factors that enhance rapid crop emergence and reduce the time that a plant is exposed to the treated soil will reduce the potential for crop injury.
Herbicides vary in their ability to translocate within a plant.
Plant injury from this type of soil-applied herbicide would be confined to the site of uptake. Other herbicides are mobile and move within the plant. Generally, plant injury symptoms associated with mobile herbicides will be most conspicuous at the location where the herbicides concentrate.