At each site a single tillage pass into no-till was used to create the tilled treatment.
In Iowa and Missouri concentrations of both atrazine and cyanazine were greatest from the tilled and no-till plots, where 100% of the contributing area was sprayed (Table 2).
The cyanazine concentration data from Missouri show significant statistical differences between tilled and incorporation for the first two runoff events (P = 0.05) and between tilled and no-till for all three events.
In Iowa, the cyanazine data shows no significant difference between tilled and no-till.
The Iowa cyanazine data shows significant differences between tilled and incorporated and between tilled and setback for runoff Event 1.