EVALUATION OF BIOCHAR AS A REMEDIATION TOOL FOR AMINOPYRALID CONTAMINATED COMPOST

Aminopyralid is a synthetic auxin herbicide which is applied to grass pastures to control broadleaf weed populations. Aminopyralid can contaminate compost through inputs derived from treated pastures such as manure and grass clippings. This possibility poses the threat of inadvertent herbicide exposure to sensitive vegetable plants through using compost contaminated with aminopyralid. Biochar can absorb pollutants and has a synergistic effect with compost when applied to the compost mixture. This study examined the relationship between biochar and aminopyralid through compost consisting of dairy manure and sawdust 1:1 mixture, aminopyralid (10μg/kg), and biochar at four treatment levels of total mass of the mixture (0%,2%,4%,10%). An initial bioassay was performed to evaluate the sensitivity of Roma tomato plants (Solanum lycopersicum cv. Roma) to aminopyralid, and to document symptomology displayed at varying concentrations of the herbicide. A final bioassay using Roma tomato plants was conducted using cured compost from our study to test for residual aminopyralid in the compost. Biochar incorporation into compost at our highest treatment interval (10%) reduced the amount of residual aminopyralid to undetectable levels through analysis. Performing the final bioassay showed that although the herbicide was undetectable symptoms were still displayed in the plants.