|Heighton Davies, Lynne|
|Abdul Baki, Aref|
Submitted to: Proceedings of the X Symposium of Pesticide Chemistry: Environmental Fate
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/1999
Publication Date: N/A
Technical Abstract: Current vegetable production systems utilize polyethylene mulch and require multiple applications of pesticides and fertilizers. During rain events, runoff from vegetable production is enhanced because 50 to 75% of the field is covered with an impervious surface. Thus, the potential harmful effects on organisms in nearby streams and rivers from off-site losses of agrochemicals is substantially increased. Recently, runoff from vegetable production on the Chesapeake Bay Delmarva peninsula has been implicated in the failure of shellfish farms. Scientists from Beltsville Agricultural Research Center have developed a more sustainable vegetable production system which utilizes vegetative mulch and has been shown to be economically viable. Little is known about the water dynamics and agrochemical fate in these systems. The objective of our research was to compare the environmental impact of these management practices by quantifying the off-site movement of pesticides and soil in runoff from polyethylene and hairy vetch (Vicia villosa Roth) mulch systems. Runoff collected from side-by-side instrumented field plots was analyzed to quantify suspended solids, dissolved-phase and particle-phase pesticide concentrations. Two to 10 times more runoff water and twice as much sediment was collected from plots with polyethylene covered beds and bare soil rows versus plots covered entirely with hairy vetch residue. Greater quantities of pesticides were lost with runoff from the polyethylene plots. Preliminary results from toxicity tests with aquatic organisms have shown greater adverse effects associated with runoff from the polyethylene mulch systems.