Analyzing Impacts of Biochar Amendment and Nitrogen Fertilization on Plant and Soil Characteristics in a Switchgrass Production System for Bioenergy

Priya Saini, Tennessee State University


The current issue of energy security and the rapid rise in carbon dioxide in the atmosphere raises the necessity for the production of bioenergy crops. The acceptance of perennial crops, like switchgrass, is important for bioenergy production and long-term carbon sequestration with added environmental and agronomic benefits. However, to meet current yield goals, larger areas under perennial grass production are required. Cultivation of switchgrass can be beneficial in two ways, first, energy can be produced from aboveground biomass to replace fossil fuels, and, secondly, by returning assimilated CO2 to the soil organic matter pool through the production and turnover of belowground biomass. Biochar, a byproduct of the bioenergy production process, is also identified as a potential tool for carbon sequestration and soil quality improvements as a soil amendment. This study investigates the effect of four nitrogen rates (0, 17, 34, and 67 kg N ha–1) and biochar application (0 and 9 Mg ha–1) in an 8-year switchgrass field study. Multiple plant and soil characteristics were analyzed for an improved understanding of switchgrass production with biochar amendment. Soil active carbon (AC) and wet aggregate stability (WAS) were analyzed to assess both the chemical and physical components of soil health. The pinewood biochar used in the study was also analyzed for several adsorption characteristics to better interpret its use as a soil amendment. Switchgrass biomass yields increased significantly from 10.36 metric tons ha–1 to 12.21 metric tons ha–1 with biochar addition to the lowest nitrogen application treatments. The addition of biochar resulted in a significant increase in soil carbon content in biochar plots. Our results also indicated a decline in both AC and WAS over the study period, similar to some other studies. Results from adsorption experiments indicated higher adsorption of ammonium ions on biochar surface at pH 8.5–9. Spectroscopic analysis also indicated presence of various functional groups on biochar surface presenting biochar as an interesting option for adsorption of ammonium further, making it available for plant uptake.

Subject Area

Plant sciences|Agriculture|Soil sciences

Recommended Citation

Priya Saini, "Analyzing Impacts of Biochar Amendment and Nitrogen Fertilization on Plant and Soil Characteristics in a Switchgrass Production System for Bioenergy" (2021). ETD Collection for Tennessee State University. Paper AAI28414372.