Date of Award

5-17-2015

Document Type

Honors Thesis

Department

Environmental Science

First Advisor

Maria Bruno

Language

English

Abstract

The weeds that are present in the landscape of the Dickinson College Certified Organic Farm, play a vital role in the agroecosystem that is created through human manipulations. The farm managers spend a great deal of time managing the weed populations on the College Farm, but little information is known about their distributions and densities in the landscape. This knowledge could better support future management strategies. This research study included a botanical collection, an inventory, which provided a systematic random sample from 85 sites over 12 acres of production fields and grass strips, and an examination of how the environmental parameters elevation (meters), slope (percent), aspect, and proximity to the grass, along with human disturbances via tillage of the landscape, influence weed growth on the College Farm. Tools in the Geographic Information System (GIS) software were utilized to help determine patterns in where the weeds are located on the College Farm and why. The results of my analysis suggest that of the 12 acres I sampled in production fields and grass strips, 45 percent of this area is covered in weeds. Common chickweed, smooth crabgrass, and dandelions are three most dominate weed species on the College Farm. A statistical t-test was used to determine whether the mean values of elevation, slope, and aspect of the 85 sites were statistically different when compared to the mean values of elevation, slope, and aspect of the sites at which common chickweed, smooth crabgrass, and dandelion were the dominant weed specie. The results of the t-test suggest that the mean values are not statistically different because the ending p-values of the test were greater than or equal to .01, which lead me to reject the null hypothesis. Therefore, the environmental parameters examined in this study do not influence the presence of the dominant weed species on the College Farm. In addition, a proximity test used in GIS rejected the hypothesis that the grass strips on the College Farm influence weed presence in the production fields. Finally, an analysis of the tillage records in the Farmdata program from 2013- 2014 ruled out the hypothesis that disturbance by tillage influenced the distribution and density of the weeds in my study. I can suggest through this research study that the weeds on the College Farm persist due to disturbed environments and already existing seedbanks. Further analysis of other parameters is recommended in future research.

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