Disapperance of atrazine, DCPA, diphenamid, diuron, linuron, norea, prometryne and trifluralin from the soil

An ideal preemergence herbicide is one that will effect adequate weed control in a crop for a suitable period of time and then disappear from the soil so that it will not cause injury to susceptible crops following in the rotation. Several herbicides being used today give full season weed control, but persist beyond the growing season, causing injury to succeeding crops.

Due to the rapid acceptance and widespread use of preemergence herbicides in the past few years, it is important to understand as much as possible about their activity, persistence in the soil and effect on later crops, especially after repeated applications.

In the spring of 1964, a 3 year study was started at two locations in Tennessee to investigate the disappearance from the soil of eight herbicides used for selective weed control. The primary objective was to determine whether such applications of herbicides would accumulate to concentrations injurious to crops being grown and to other crops that would follow in a rotation.