Submitted to: Advances in Water Resources
Publication Type: Abstract Only
Publication Acceptance Date: April 27, 2008
Publication Date: N/A
Technical Abstract: A common management practice for the production of fresh-market vegetables uses polyethylene (plastic) mulch to increase soil temperature, maintain soil moisture and reduce weed pressure. However, multiple applications of fungicides and insecticides are required, and rain events afford more runoff and soil erosion because 50 to 75% of the field is covered with an impervious surface. Research was conducted to quantify soil loss and pesticide transport with runoff from the conventional plastic mulch (Poly-Bare: polyethylene covered raised beds with bare soil furrows) and two alternative vegetative mulch systems (Poly-Rye: polyethylene covered raised beds with Secale cereale furrows; Vetch: raised beds and furrows covered with Vicia villosa residues). Planting cereal rye in the furrows between the polyethylene mulch beds decreased runoff volume by more than 40%, soil erosion by more than 80%, and pesticide loads by 48-74%. Replacing polyethylene mulch and bare soil furrows with hairy vetch residues on both the beds and the furrows further reduced runoff volume, soil erosion and pesticide transport with runoff. The ability of these alternative management practices to reduce the ecological risk of pesticides was also evaluated. Runoff from the conventional Poly-Bare presented the greatest risk to ecosystem health and to sensitive organisms, whereas the use of Vetch minimized these risks. Harvest yield data together with these results indicate that the alternative management practices (Poly-Rye and Vetch) have a less adverse impact on the environment than the conventional management practice (Poly-Bare) while providing growers with an acceptable economic return. In addition, this research demonstrates the need to consider the management practice when assessing the potential risks and hazards for certain pesticides.