No abstract

Imidazolinones are polar herbicides with high leaching potential making them potential threat to environment quality. Biochar, a carbon sorbent, can efficiently stabilize substances and could be used to reduce the pesticides leaching. This work was conducted to study biochar effects on leaching of imazapic, imazapyr, and a mixture of them (Onduty®) for the first time. Leaching columns were used during lab experiments. Soil amendment with biochars produced from oil palm empty fruit bunch and rice husk significantly reduced the herbicides leaching percentages. 16% of imazapic was leached from biochar-free soil. For rice husk and empty fruit bunch biochar-amended soils the amounts were 4.3% and 3.6%, respectively. The highest percentage of imazapyr was leached out from non-amended soil (14.2%) followed by rice husk (4.0%) and empty fruit bunch (2.8%) biochar-amended soils. 15.2% of the applied Onduty® was leached from non-amended soil. Rice husk and empty fruit bunch biochars could reduce the herbicide leaching to 4.2% and 3.0%, respectively. Soil amended with biochars retained the higher percentages of the herbicides in top 7.5 cm depths. Total herbicides amounts adsorbed by biochars were more than 95%. It was concluded that biochar application has the potential to decrease imidazolinones leaching and their environmental pollution.