Graduate Exit Seminar

Lumarie Pérez-Guzmán will present her Graduate Exit Seminar at 12:30 p.m. in 333 Kottman Hall. Her presentation is Microbial Activity, Abundance and Diversity in Organic and Conventional Agricultural Soils Amended with Biochars. 

Biochar, the product of thermal decomposition of biomass, has been proposed as a means to improve soil quality and to sequester carbon. It is important to determine its effect on soil microorganisms as they control all fundamental soil functions. Research on biochar has had mixed effects on microbial communities; however most studies have been done at very high biochar rates that are not practical at field levels, and have used a single biochar type. Therefore, the objective was to determine the effect of diverse biochars and application rates on soil microorganisms.  Microbial abundance, diversity and community structure were determined by analysis of phospholipid fatty acids (PLFA), amplification of the 16S rRNA and 18S rRNA genes, denaturing gradient gel electrophoresis (DGGE) and next-generation sequencing (NGS).  Microbial activity was assessed by measuring the enzyme activities of fluorescein diacetate (FDA) hydrolysis and β-glucosidase. Results showed no difference in FDA activity in soils amended with biochar when compared to control.  Conversely, biochars increased the activity of β-glucosidase as well as the abundance and diversity of fungal communities.  Furthermore, the addition of biochars significantly (p < 0.001) changed the relative abundance of bacterial phyla causing shifts in microbial populations.  These results suggest that biochar can influence changes in microbial community composition and microbial activity.

Brian H. Lower and Richard P. Dick, co-advisors