Jim Martin and J.D. Green, Extension Weed Scientists, University of Kentucky
Dry soil conditions can enhance persistence of herbicides such as atrazine. Kentucky has had dry seasons in the past, yet atrazine injury to rotational crops was seldom an issue. Having said that, the risk of crop injury due to atrazine carryover is still an issue that we need to consider on a case by case basis. The risk will be reduced if atrazine was applied early spring and had some rain to move into the soil profile. Prolonged periods of dry soil will enhance persistence and increase the chance of injuring rotational crops. If weather conditions improve and we have a mild and wet fall and winter, then the risk of carryover to spring planted crops will be reduced. Using high rates of atrazine will increase the risks. Atrazine may dissipate more rapidly in no-till compared with tilled conditions. High soil pH (pH >7.0) will increase atrazine persistence.
Dry soil conditions can enhance persistence of herbicides such as atrazine. Kentucky has had dry seasons in the past, yet atrazine injury to rotational crops was seldom an issue. Having said that, the risk of crop injury due to atrazine carryover is still an issue that we need to consider on a case by case basis. The risk will be reduced if atrazine was applied early spring and had some rain to move into the soil profile. Prolonged periods of dry soil will enhance persistence and increase the chance of injuring rotational crops. If weather conditions improve and we have a mild and wet fall and winter, then the risk of carryover to spring planted crops will be reduced. Using high rates of atrazine will increase the risks. Atrazine may dissipate more rapidly in no-till compared with tilled conditions. High soil pH (pH >7.0) will increase atrazine persistence.
