Paul Bartley

Former Graduate Student

Degree: Ph.D., 2019

Thesis Title: Multidimensional Characterization of Horticultural Substrates

Paul graduated from Auburn University in 2013 with his undergraduate degree in Horticulture, focusing on nursery and greenhouse production. Desiring to pursue his Ph.D. in horticultural crop production, he utilized his previous work experience in weed management to earn his master’s degree in 2015, also at Auburn University. In January 2016, Paul joined the NC State Substrate Science Team in pursuit of his doctorate degree. Paul’s research is focused on substrate particles, particle performance, and particle characterization. Horticultural media may be simply defined as a conglomerate of particles or aggregate material used to provide support, water, air, and nutritional requirements essential to plant growth in containers. The characteristics of any substrate material can be attributed to its composition of particle characteristics. Sieve analysis is one of the most basic tests for fractioning particle sizes of substrate materials and has been the predominant method utilized for the characterization of horticultural media. However, sieve analysis is noted for its poor reproducibility and lack of valuable information. As modern agriculture endeavors for precision and reproducibility, the essential component in container production, media, must be better understood. To better quantify the role of particle shape and size, new technologies currently used in the fields of engineering and medicine are evaluated for their potential use in substrate science. A Computer Particle Analyzer II by W.S. Tyler Group is capable of analyzing material and providing a quantifiable 2-D characterization of each particle in a substrate. Advances in X-ray technology, software, and commercially available instruments have opened the door for the use of X-ray microtomography in substrate research, potentially providing unprecedented 3-D, in situ characterization of substrate particles, pore structure, and root architecture.

Paul C. Bartley III