Quantifying biochar content in a field soil with varying organic matter content using a two-temperature loss on...

Area of Science:

• Soil Science
• Environmental Science
• Analytical Chemistry

Background:

• Biochar is increasingly used as a soil amendment for agricultural and environmental benefits.
• Accurate quantification of biochar in soil is essential for assessing its effectiveness and environmental impact.
• Current methods for biochar quantification in soil are often complex and time-consuming.

Purpose of the Study:

• To develop a rapid, simple, and cost-effective method for quantifying biochar content in field soils.
• To address the challenge of accurately measuring biochar in soils with variable organic matter content.

Main Methods:

• The study introduces a two-temperature loss on ignition (LOI) method.
• This technique involves sequential heating of biochar-soil mixtures at a low temperature (LT) and a high temperature (HT).
• The method relies on the differential mass loss between pure soil and pure biochar at selected LT and HT, assuming uniform SOM chemical composition.

Main Results:

• The two-temperature LOI method accurately estimated biochar content in roadway filter strip soils.
• Results showed close agreement between the method's estimates and independent measurements for both low and high biochar mass fractions.
• The method demonstrated reliability across varying soil organic matter (SOM) levels.

Conclusions:

• The developed two-temperature LOI method offers a practical solution for quantifying biochar in soils.
• This technique is suitable for soils with low to moderate SOM content and biochars produced at moderate to high temperatures with low ash content.
• The method facilitates better assessment of biochar application in agronomic and environmental management.