|Lerch, Robert - Bob|
Submitted to: North American Agroforestry Conference
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2009
Publication Date: 5/31/2009
Citation: Lin, C., Lerch, R.N., Garrett, H.E., Udawatta, R. 2009. Implementation of Contour Vegetative Buffers for Mitigating of Atrazine in Ground Water [abstract]. North American Agroforestry Conference. p. 201. Interpretive Summary:
Technical Abstract: The efficacy of vegetative buffer strips (VBS) in intercepting herbicides from surface runoff is well established. However, effect of VBS on fate of the atrazine in ground water has not been widely studied. An established, well calibrated paired watershed consisting of 1) a corn-soybean/tree-grass buffer, 2) a corn-soybean/contour grass buffer, and 3) a control treatment with a corn-soybean rotation only was utilized to evaluate the effect of vegetation buffers and topographic factors on degradation of atrazine in groundwater. The grass buffer strips are 4.5 m wide consisting of the following forages: redtop (Agrostis gigante Roth), brome grass (Bromus spp.), and birdfoot trefoil (Lotus corniculatus L.). Corn-soybean width is 36.5 m. This pattern is repeated five times over the landscape. Tree-grass buffer treatments include pin oak (Quercus palustris Muenchh.), swamp white oak (Q. bicolor Willd) and bur oak (Q. macrocarpa Michx.) mixed with the same grass species. Buffer width is 4.5 m. Sixty PVC lysimeters (5 cm diameter x 100 cm long) were implemented at depths 30 cm cross landscape positions (summit, shoulder slope, and foot slope) to monitor the water quality in subsurface flow before, between and after passing through the buffer strip. A similar implementation was applied at the same topographic elevation for the control. The groundwater samples were collected from lysimeters over time after major rainfall events. Samples were filtered, refrigerated and analyzed for atrazine and its metabolites. Our result suggested that the ratios of metabolite-to-parent atrazine in ground water were significantly increased by vegetative buffers practices. Therefore, the implementation of VBS would help to promote the biodegradation of atrazine and improve the ground water quality.