College of Agriculture & Natural Resources
Permanent URI for this communityhttp://hdl.handle.net/1903/1598
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Evaluation of organic inputs for reducing dollar spot disease on cool-season turfgrasses(2018) Beckley, Cody James; Roberts, Joseph A; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Lolium perenne, Poa annua, and Agrostis stolonifera are turfgrass species commonly grown on golf course fairways; however, they are susceptible to dollar spot (Clarireedia spp.). Field studies were conduction to assess: 1) the effects of organic fertilizer treatments and fungicide programs on dollar spot severity; and 2) the impact of organic amendments on dollar spot severity and residual fungicide efficacy. Alternating applications of organic and conventional fungicides reduced seasonal dollar spot severity to the same degree as conventional fungicides. Dollar spot was more severe in Lolium perenne and Poa annua treated with organic fungicides. On A. stolonifera, organic biosolids compost, biochar, and vermicompost amendments suppressed dollar spot to the same degree as conventional fertilizer in year one of the trial, while dollar spot was more severe on A. stolonifera fertilized with organic biosolids compost in year two. Fertilizer treatments had no effect on residual fungicide efficacy on A. stolonifera.Item Manure as a Natural Resource: Alternative Management Opportunities(University of Maryland Extension, 2014-12) Miller, Jarrod; Moyle, JonManure, as a source of organic matter and plant nutrients, is an excellent conditioner for soils. As fertilizer in agronomic systems, manure can cycle nutrients between soils, plants and livestock. However, in areas where livestock become concentrated and limited land is available for application, excess nutrients can lead to water quality issues. If manure application is to be locally restricted, alternative uses must be found. These uses can be simple, such as transporting to nutrient poor regions, or require more complex infrastructure, such as energy production or nutrient extraction.Item Comparison of Pathogen Detection Methods in Compost and Compost Characteristics as Potential Predictors of Pathogen Regrowth(2013) Reynnells, Russell Edward; Felton, Gary; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Improperly thermally treated compost can allow human pathogens to survive. Pathogens can regrow in finished compost due to recontamination or incomplete pathogen-kill. U.S. Environmental Protection Agency's (EPA) and U.S. Composting Council's (USCC) methodologies were compared to recover populations of inoculated non-pathogenic E. coli and pathogenic Salmonella spp. from finished compost. Two immunomagnetic separation (IMS) techniques were additionally compared for the rapid recovery of inoculated pathogenic E. coli O157:H7. Twenty-nine point-of-sale composts were obtained from 19 U.S. states. EPA methods recovered more (generic E. coli, p=0.0001) or statistically equal (Salmonella, p=0.27) amounts of inocula compared to USCC methods. Both IMS techniques identified with 3-4% false negatives among replicates. Physicochemical parameters of compost were tested as predictors of Salmonella and O157:H7 regrowth in finished compost. Salmonella and O157:H7 populations increased over three days in 48% and 52% of compost samples, respectively. No physicochemical measurements could predict the regrowth of Salmonella or O157:H7.Item Assessment of Foodborne Pathogen Survival During Production and Pre-harvest Application of Compost and Compost Tea(2009) Ingram, David Thomas; Joseph, Sam W; Meng, Jianghong; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The use of compost in crop production systems as a soil amendment is recognized by both conventional and organic plant production practitioners as a means to increase yields and reduce the incidence of foliar diseases. Compost tea (CT), an aqueous extract of the biological components of compost, is also recognized as a means to broadcast the phytopathogen-reducing components of compost directly to the surfaces of plants where many foliar diseases become established. CT has been shown to control the proliferation of a variety of foliar diseases in many turf, crop and horticulture production systems when applied directly to the foliar surfaces of plants. This dissertation research was designed to address several pre-harvest food safety issues concerning compost and compost teas. Three objectives were pursued to establish whether the use of compost and compost teas as pre-harvest practices may introduce foodborne pathogens into the food supply and, therefore, contribute to the incidence of foodborne illness. The first objective involved a microbiological survey of commercially available compost in the U.S. to determine the prevalence of fecal coliforms, Escherichia coli, Salmonella and enterococci that might be reaching consumers through contaminated fruit and vegetables. The second objective was to investigate the ability of these foodborne pathogens to propagate during the production of CT. The third objective involved a field study examining the potential of CT to disseminate E. coli into organic and conventional strawberry production systems. The effects of CT on the fruit yield, phytopathogen suppression, as well as the potential for foodborne pathogen survival on the fruit surfaces were examined. This project provided important information and recommendations for the safe production and pre-harvest application of compost and compost teas. It was contended that, with proper attention to the manufacture and storage of compost and with simple modification of current trends in CT production systems, the current threshold of pre-harvest introduction of foodborne pathogens could be significantly reduced.