Reduction of 2,4-D Load in Surface Runoff Down a Grassed Waterway
1977
Asmussen, L. E. | White, Anthony W. | Hauser, E. W. | Sheridan, J. M.
The effectiveness of a grassed waterway in decreasing 2,4-D [(2,4-dichlorophenoxy) acetic acid] content in surface runoff was investigated. Corn (Zea mays L.) plots were treated with 2,4-D (0.56 kg/ha) and runoff produced by applying simulated rain was directed through a 24.4-m-long grassed waterway. The 2,4-D concentrations were measured under wet and dry antecedent waterway and plot conditions. Reduction in 2,4-D load in waterways results from water loss by infiltration, sediment loss, and by attachment-absorption on vegetative and organic matter. Of the simulated rainfall applied 1 day after application of 2,4-D, 50% of the water ran off the plots under dry antecedent soil conditions, and 78% ran off under wet conditions. Infiltration reduced runoff flowing down the waterway an additional 25% under dry conditions and 2% under wet conditions. Suspended sediment reduction in the waterway was 98 and 94% of the total amount moving from the plot for the dry and wet waterway conditions, respectively. The total loss (on sediment and in solution) of the applied 2,4-D from the plot in the dry and wet states was 2.5 and 10.3%, respectively. Of the 2,4-D lost from the plots and entering the 24.4-m waterway, approximately 30% reached the end of the waterway, regardless of antecedent soil moisture.
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