Source: Agricultural Research Service

Researchers have discovered that it's more important to know the crop and herbicide use history than the timing and amount of irrigation water used to enhance the herbicide's efficacy.

ARS plant physiologists Dale Shaner and Lori Wiles made this discovery from ongoing experiments on two irrigated fields at Colorado State University (CSU) at Fort Collins, Colo. 

In collaboration with CSU colleague Neil Hansen, Shaner and Wiles compared the behavior of the herbicide atrazine in conventionally tilled corn grown continuously year after year versus corn grown in three different crop rotations. They tested various levels of tillage and irrigation, including no irrigation.

Original press release