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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #409721

Research Project: Developing Agronomically and Environmentally Beneficial Management Practices to Increase the Sustainability and Safety of Animal Manure Utilization

Location: Food Animal Environmental Systems Research

Title: Aminopyralid herbicide residual concentration in dairy manure composted with biochar

item NETTHISINGHE, ANNESLY - Western Kentucky University
item WOOSLEY, PAUL - Western Kentucky University
item Agga, Getahun
item STRUNK, WILLIAM - Western Kentucky University
item PARRIS, STEVEN - Western Kentucky University
item Sistani, Karamat

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2023
Publication Date: 9/14/2023
Citation: Netthisinghe, A., Woosley, P., Agga, G.E., Strunk, W., Parris, S., Sistani, K.R. 2023. Aminopyralid herbicide residual concentration in dairy manure composted with biochar [abstract]. American Society of Agronomy Meetings.

Interpretive Summary:

Technical Abstract: Aminopyralid is an auxin type herbicide in the pyridinecarboxylic acid family that is used widely to control broad leaf weeds in pastures. Grasses sprayed by aminopyralid herbicide and any products derived from those grasses such as hay, straw, manure, bedding, and compost can potentially be contaminated. Straw, hay, and compost all are used as mulches and manure and composts are used to fertilize and build soil. Aminipyralid residues remaining in compost may pose threat to plant growth when the compost is introduced to the soils. Biochar is produced from biomass sources for the purpose of transforming the biomass carbon into a more stable form. Biochar has a high sorption capacity for organic pollutants, which is driven by its physicochemical properties, such as the large surface area and porosity, and also by its surface chemistry. This research examined residual concentrations of aminopyralid in dairy manure composted with 0%, 2%, 4%, and 10% (w/w) biochar levels with initial 10 ppb (wet) concentration[ ~35 ppb (dry basis)]. After 6 month composting period both 0% and 2% biochar treatments contained 15-20 ppb (dry basis) aminopyralid residual concentration. Residual aminopyralid was not detected in the three replicates of 4% biochar treatment and in all the 10% biochar treatment replicates. The bioassay test conducted with tomato seedlings revealed that all the composted material showed some injury symptoms, but the mean injury index (Max = 3.0) of top 3 leaves in the10% biochar treatment was significantly lower that the 0%, 2% and 4% biochar treatments (0.99 vs. 1.43-1.75). Plant analysis results showed residual aminopyralid concentration gradient from 15.6 ppb (10% biochar treatment) to 54.9 ppb (0% biochar treatment) indicating much lower residual concentrations below the method detection limit (4 ppb- dry) may have existed in the composts of 4% and 10% biochar treatment.