By Blake Jackson
Findings from a two-year field study conducted by Kentucky State University and published in Frontiers in Agronomy highlight a potential solution to two persistent challenges in soybean production—soil acidification and declining soil organic carbon. The research focused on the use of pine sawdust biochar in acidic silt loam soils under continuous soybean cultivation.
Researchers applied biochar annually at a rate of 12 tons per hectare, incorporating it into the top 15 centimeters (5.9 inches) of soil before planting. Soil samples were collected both before planting and after harvest to evaluate changes in acidity, organic carbon levels, fertility, and water-related properties.
After two growing seasons, results showed that plots treated with biochar maintained higher soil pH levels following harvest and saw an increase in soil organic carbon from 1.74% to 1.96%.
However, the study found no significant short-term changes in soil fertility or hydrological characteristics, indicating that biochar functions more as a long-term soil stabilizer than a quick nutrient source.
The research was led by Binaya Baral with guidance from Dr. Anuj Chiluwal, assistant professor of agronomy, at Kentucky State’s Harold R. Benson Research and Demonstration Farm. Baral published the findings as first author in the peer-reviewed paper, “Response of acidic silt loam soil properties to biochar application under soybean cultivation.”
“Acidic soils can limit soybean growth by reducing nutrient availability and interfering with biological nitrogen fixation,” Baral said. “Our research shows that biochar can help buffer soil acidity and improve soil carbon over time.”
Dr. Chiluwal emphasized that biochar should be viewed as a long-term amendment rather than a fertilizer substitute, adding that further research is needed to determine cost-effective application rates for producers.
The study was supported by a USDA-National Institute of Food and Agriculture 1890 Capacity Building Grant.
Photo Credit: gettyimages-zoran-zeremski
Categories: Kentucky, Crops, Soybeans, Education