Semester

Fall

Date of Graduation

2013

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Horticulture

Committee Chair

Sven Verlinden

Committee Co-Chair

James Kotcon

Committee Member

Nicole Waterland

Abstract

Marked improvements in the sustainability of the horticulture industry have occurred over the last few decades. Movement towards better management practices in areas such as pesticide (IPM), fertilizer application and water usage characterizes today's industry. However, several obstacles have to be overcome for true long-term sustainability of the ornamental horticulture industry. One of these obstacles is the abundant use of plastics in the horticulture industry. This research focused on reducing the industry's plastic waste stream by evaluating the effects of biodegradable pots on plant growth parameters and substrate chemistry, as well as characteristics of biodegradable pots such as strength and algal/fungal growth. Plastic pots have become an industry standard, but do have two important limitations. The container walls are impermeable; therefore when the roots contact the surface, they tend to circle the container. Circling of roots in turn results in poor landscape establishment. The other limitation to plastic is the issue of proper disposal. While plastics represent only 7% of the waste stream by weight, they take up 20% of the waste stream by volume. Recycling of horticultural products such as plastic containers is further complicated by contamination, such as dirt residue, grease, vegetation, moisture, pesticide contamination, and ultraviolet light degradation. In 2009, the EPA found that nationwide, only 7.1% of 29 million tons of plastic was recycled. An alternative to plastic pots is biodegradable pots. Biopots are defined as pots not made from petroleum, that degrade rapidly. Despite their potential as a sustainable alternative to plastic pots, recent studies focusing on the water use of biopots have found that some biodegradable containers require more frequent irrigation and can be significantly weaker than plastic pots, especially when wet. We investigated plant growth, watering frequency, pot strength, pot algal growth, denesting times, and percent degradation of biodegradable pots. Few differences were observed in plant growth. Wood fiber, peat, and manure pots showed lower pot strength, higher amounts of algal growth, and required a higher watering frequency compared to the control plastic pot in all trials. Peat pots required significantly more time to denest, and manure pots showed higher degradation in the field compared to all other pots. All pots studied were capable of producing a marketable plant. These results suggest that biodegradable pots do show potential as replacements for plastic pots, but factors such as pot strength, algal growth, and ease of denesting will be important to their adoption by the industry.

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