The 2011 ASHS Annual Conference

The ecological impacts of invasive species are primarily due to their rapid growth, clogging waterways as well as outcompeting, even completely displacing native species; which can result in the reduction of native population densities, species diversity, and richness.  As a waste management system within agriculture, the composting process has been shown to kill plant pathogens and weed seeds if high enough temperatures are obtained for long enough periods of time.  Compost has also been used in the horticulture industry to decrease plant disease(s), increase the accessibility of nutrients by plants, and as an effective weed control agent.  The purpose of this study was to investigate the effectiveness of a large-scale composting operation to manage invasive plants, water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), hydrilla (Hydrilla verticillata), and Georgia cane (Arundo donax), by rendering the seeds and other propagules non-viable while producing a valuable compost product for the agricultural and horticultural industries.  The invasive species of interest were subjected to germination and oven kill tests, to evaluate if the composting process has the potential through high temperatures to kill seeds and other propagules.  Samples of water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), hydrilla (Hydrilla verticillata), and Georgia cane (Arundo donax) plants were obtained by the researcher during the mid to late summer months (when flowering and fruiting).  A mini-incubator was used for the germination tests, where unscarified and scarified seeds were placed in petri dishes on filter paper moistened with distilled water, held for 14 days at 80.0 degree Fahrenheit, and then observed for radical emergence.  Oven kill tests determined at which temperature seeds and other propagules are rendered nonviable.  The oven kill tests included unscarified and scarified seeds and other propagules that were held for three days at temperatures of 120, 135, and 150 degrees Fahrenheit.  In the field, windrow compost piles were constructed using the recipe: 50% woodchips, 25% cafeteria food waste, and 25% invasive species.  Results demonstrate if invasive species can be used to produce a nutrient rich resource for various applications within the horticulture industry, while also effectively managing invasive species.