Submitted to: North American Agroforestry Conference
Publication Type: Proceedings
Publication Acceptance Date: 8/7/2001
Publication Date: N/A
Technical Abstract: Multi-species grass riparian buffer strip systems have been recognized as one of the most cost-effective bioremediation approaches to alleviate nonpoint-source agricultural pollution. Thirty-six 1-m wide and 0.5-m deep fluorinated lysimeters with 6 different ground covers (bare ground, tall fescue, smooth bromegrass, orchardgrass, timothy, and switchgrass) were established in 1998 to evaluate the bioremediation capacity of the vegetated ground cover on Balance, atrazine, and nutrient removal. Herbicides and nutrient were applied uniformly to each lysimeter with irrigation of 3L solutions containing nitrate (50 ppm) with atrazine (500 ppb) or Balance (80 ppb). The effluent of each lysimeter was sampled as a function of time and the soil and plant were sampled after 25 days of application. The concentrations of atrazine, balance, and their metabolites in the leachate, soil, and plant were determined by solid phase extraction and HPLC-UV, HPLC-MS, HPLC-MS/MS, and GC-MS/MS methods. The distribution o the herbicides and their metabolites in the system was calculated using a mass balance approach. Bioremediation capacity of each species was determined by metabolites/parent herbicide ratio and nitrate levels in the system. Based on the derived degradation data, a tree-shrub-grass riparian buffer design was proposed to maximize the bioremediation capacity on herbicide and nutrient removal from surface and subsurface flow.