PESTICIDE LEACHING UNDER DIFFERENT IRRIGATION SYSTEMS

Authors: SINGH, G. - U.C. RIVERSIDE; SPENCER, W. - 5310-20-05 (COLLABORATOR); Yates, Scott

Submitted to: Clean Water Clean Environment 21st Century Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/22/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: To develop better understanding of how water and pesticide applications can be controlled to reduce pesticide transport to groundwater, pesticide transport studies were coupled with water management practices to evaluate the effectiveness of water application methods in reducing pesticide transport in two large scale field experiments.

Technical Abstract: The effect of different irrigation management systems on pesticide transport toward groundwater was evaluated under field conditions. In Experiment 1, during a 2-year period, soil profile and shallow groundwater samples were analyzed for pesticides applied to cotton grown with four irrigation systems, i.e., subsurface drip (SSD), low-energy yision application (LEPA), conventional, and improved furrow. There was no apparent difference in soil distribution of pesticide residues below the 20-inch depth among the four irrigation treatments, although some shallow groundwater samples were found to contain pesticides with concentration somewhat higher in the existing and improved furrows than in LEPA or SSD fields. In Experiment 2 at Shafter, California, on a sandy loam soil, high concentrations of pesticides were observed in the surface soil of SSD plots than in furrow irrigated ones, but no residues were found below 20-inch depth in either irrigation system. The effect of injecting polyacrylamide at 5-10 ppm in irrigation water on sediment and pesticide load in runoff water was evaluated. The polymer application significantly reduced the sediment load and kelthane concentrations in runoff from a furrow irrigated lima bean field..