Kentucky State research published in Frontiers in Agronomy finds pine sawdust biochar can help buffer soil acidity and build soil carbon under soybean cultivation

FRANKFORT, Ky. ā€” Findings from a two-year Ā鶹ֱ²„ field study are now available in Frontiers in Agronomy, pointing to a promising soil management strategy for addressing two long-term challenges in soybean production: soil acidification and declining soil organic carbon.

The study evaluated pine sawdust biochar in acidic silt loam soils under continuous soybean cultivation. Researchers applied biochar at 12 tons per hectare each year, incorporating it into the top 15 centimeters of soil before planting. Soil samples were collected before planting and after harvest to assess acidity, organic reserves, fertility, and hydrological properties.
Biochar Collage

After two years, biochar-treated plots maintained higher post-harvest soil pH and increased soil organic carbon from 1.74% to 1.96%. The paper also notes that the treatment did not significantly change soil fertility or water-related properties during the study period, reinforcing biocharā€™s role as a longer-term soil stabilizer rather than an immediate fertility enhancer.

The study was conducted by Binaya Baral under the mentorship of Dr. Anuj Chiluwal, assistant professor of agronomy, at Kentucky Stateā€™s Harold R. Benson Research and Demonstration Farm.

Binaya Baralā€œAcidic soils can limit soybean growth by reducing nutrient availability and interfering with biological nitrogen fixation,ā€ Baral said. ā€œOur research shows that biochar can help buffer soil acidity and improve soil carbon over time.ā€

Dr. Chiluwal said the Kentucky State findings show biocharā€™s value as a long-term soil amendment rather than an immediate fertilizer replacement. Future multi-rate studies are needed to identify practical and cost-effective application rates.

Baral published the findings as first author in the peer-reviewed paper, ā€œ.ā€ Dr. Chiluwal serves as the corresponding author. Co-authors include Deepak Khatri, former research associate in agronomy; Sudip Poudel, research associate in crop physiology; Lalit Pun Magar, former research associate in precision agriculture; and Dr. Atanu Mukherjee, a former Kentucky State faculty member.

Baral earned a Master of Science in Environmental Studies from Kentucky State in 2026 and is now a Graduate Research Assistant and Ph.D. student in the Department of Agricultural and Biological Engineering at the University of Florida. His current research focuses on best management practices-based sod rotation and integrated crop-livestock systems to improve nutrient management, reduce nitrogen leaching, and sustain crop productivity in Floridaā€™s sandy soils using field data, DNDC modeling, and AI/machine learning approaches.

The study is part of ongoing research supported by the USDA-National Institute of Food and Agriculture 1890 Capacity Building Grant, Award Number 2023-38821-39960, to Ā鶹ֱ²„.