EFFECTS OF ORGANIC AND CONVENTIONAL AGRICULTURAL PRACTICES ON SOIL MICROBIAL COMMUNITIES AND MOLECULAR DETECTION OF SOIL BORNE DISEASE

(Under the direction of Tiehang Wu) Agricultural practices affect soil microbial communities and health through the input of pesticides, herbicides, fertilizers, and cycling of crop rotation. By examining the microbial community structure, we analyzed how microbial species respond to the environment that individual farms create. Early detection of soil borne disease is essential for agricultural success. However, monitoring incidence of disease based on plant growth response to pathogenic inoculation may not reveal the amount of pathogenic DNA in soil. A comparative study of tomato production systems was conducted by analysis of soil microbial community structure from four farms in Southeast Georgia for the years 2012 and 2013, and incidence level of disease and plant growth of tomato plants grown in greenhouse soil were measured. The results indicated that the soil fungal, bacterial, and animal communities were unique to each farm (ANOSIM P<0.0001) for 2012 and 2013. The soil chemical characteristics were significantly different between each farm (MANOVA, P<0.0001) for both years. Calcium base saturation and soil p