Date of Graduation


Document Type


Degree Name

Bachelor of Science in Biological Engineering

Degree Level



Biological and Agricultural Engineering


Runkle, Benjamin

Committee Member/Reader

Haggard, Brian

Committee Member/Second Reader

Naithani, Kusum

Committee Member/Third Reader

Runkle, Benjamin


The overall goal of this study was to provide a measure of the decomposition rate constant on a semi- intensive green roof located in Fayetteville, Arkansas. The specific approach chosen was the use of the Tea Bag Index (TBI), a standardized plant litter decomposition test. There was some heterogeneity observed on site and the locations of samples tested were chosen based on this. Additional laboratory tests were conducted in order to determine whether there would be a large impact of temperature on decomposition or if it would be outweighed by other factors. The temperatures compared were 5°C, 20°C, and 30°C. Decomposition data collected in the laboratory test fit to some extent with the exponential decay model suggested (0.9 > P > 0.85). This data suggests a comparable rate of decomposition to other biomes which had been previously studied, which was further supported by samples tested on site. The decomposition rate constants calculated from data collected on site were slightly less than those seen in grasslands or healthy forests but higher than those seen in more arid environments. The stabilization factor was more similar to those seen in sandy soils, which fits with the composition of the engineered soil used. The main recommendation for future research is replication during the summer months, which could confirm the influence of season or temperature on decomposition while further assessing soil health at the site.


Tea Bag Index, Decomposition, Green Roof, Decomposition Rate