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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Factors affecting nitrogen nutrition of western hemlock /

Gill, Ranjit Singh. January 1981 (has links)
Thesis (Ph. D.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 93-98). Also available on the World Wide Web.
32

Assessment of chemical exposure and self-reported health among tree planters in British Columbia

Gorman, Melanie Johanna 11 1900 (has links)
In British Columbia harvested forests are manually replanted by seasonal workers. Fertilizers contained in perforated paper sachets are often planted with seedlings. There have been anecdotal reports of skin and respiratory illness associated with fertilizer exposure and due to potential metal content in fertilizer source material they may contain metals as contaminants. Workers may also be exposed to pesticide residues on seedlings. This study aimed to characterize fertilizer, metal and pesticide exposure among a sample of B.C. tree planters, and to examine worker respiratory and dermal health. Between May 2006 and April 2007 223 tree planters were interviewed about their respiratory and dermal health, and the exposures of 54 tree planters at five geographically-disperse worksites were monitored. Four worksites were using fertilizer and one was not. The health questionnaire was a modification of the American Thoracic Society standardized questionnaire with questions on dermal health taken from a previous UBC study. Workers were grouped in exposure categories and symptoms analysed using logistic regression. Metals were measured by ICP/MS on post shift hand wipes, full shift air sample filters, in whole blood, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post shift hand wipes and on bulk seedling samples. Using nursery pesticide application records, analyses focused on known pesticides applied to the seedlings at the study sites. Carbamate pesticides were analyzed by HPLC/MS and other pesticides by GC/MS. No evidence was found that tree planters who work with fertilizer are at an elevated risk of exposure to arsenic, lead, cadmium, chromium and nickel relative to other tree planters. Pesticide residues were found on seedlings taken from coastal work sites in April 2007. At coastal worksites the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37 – 106.3 ng.cm² and 0.48 – 15.9 ng/cm² respectively). Work with fertilizer was linked with an increased risk of cough, phlegm, nasal symptoms, nose bleed, and skin irritation. Hygiene conditions at tree planting work sites are very poor. Although measured exposures were low, hygiene conditions should improve to reduce the risk of health symptoms among tree planters.
33

Assessment of chemical exposure and self-reported health among tree planters in British Columbia

Gorman, Melanie Johanna 11 1900 (has links)
In British Columbia harvested forests are manually replanted by seasonal workers. Fertilizers contained in perforated paper sachets are often planted with seedlings. There have been anecdotal reports of skin and respiratory illness associated with fertilizer exposure and due to potential metal content in fertilizer source material they may contain metals as contaminants. Workers may also be exposed to pesticide residues on seedlings. This study aimed to characterize fertilizer, metal and pesticide exposure among a sample of B.C. tree planters, and to examine worker respiratory and dermal health. Between May 2006 and April 2007 223 tree planters were interviewed about their respiratory and dermal health, and the exposures of 54 tree planters at five geographically-disperse worksites were monitored. Four worksites were using fertilizer and one was not. The health questionnaire was a modification of the American Thoracic Society standardized questionnaire with questions on dermal health taken from a previous UBC study. Workers were grouped in exposure categories and symptoms analysed using logistic regression. Metals were measured by ICP/MS on post shift hand wipes, full shift air sample filters, in whole blood, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post shift hand wipes and on bulk seedling samples. Using nursery pesticide application records, analyses focused on known pesticides applied to the seedlings at the study sites. Carbamate pesticides were analyzed by HPLC/MS and other pesticides by GC/MS. No evidence was found that tree planters who work with fertilizer are at an elevated risk of exposure to arsenic, lead, cadmium, chromium and nickel relative to other tree planters. Pesticide residues were found on seedlings taken from coastal work sites in April 2007. At coastal worksites the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37 – 106.3 ng.cm² and 0.48 – 15.9 ng/cm² respectively). Work with fertilizer was linked with an increased risk of cough, phlegm, nasal symptoms, nose bleed, and skin irritation. Hygiene conditions at tree planting work sites are very poor. Although measured exposures were low, hygiene conditions should improve to reduce the risk of health symptoms among tree planters.
34

Urea leaching in a sandy soil

Spiro, David Alan, January 1972 (has links) (PDF)
Thesis (M.S. - Department of Hydrology and Water Resources and Department of Soil, Water, and Engineering)--University of Arizona. / Includes bibliographical references.
35

Study of the pathway of heavy metals in a sewerage system /

Halday, Ismail. January 2007 (has links)
Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography.
36

Assessment of chemical exposure and self-reported health among tree planters in British Columbia

Gorman, Melanie Johanna 11 1900 (has links)
In British Columbia harvested forests are manually replanted by seasonal workers. Fertilizers contained in perforated paper sachets are often planted with seedlings. There have been anecdotal reports of skin and respiratory illness associated with fertilizer exposure and due to potential metal content in fertilizer source material they may contain metals as contaminants. Workers may also be exposed to pesticide residues on seedlings. This study aimed to characterize fertilizer, metal and pesticide exposure among a sample of B.C. tree planters, and to examine worker respiratory and dermal health. Between May 2006 and April 2007 223 tree planters were interviewed about their respiratory and dermal health, and the exposures of 54 tree planters at five geographically-disperse worksites were monitored. Four worksites were using fertilizer and one was not. The health questionnaire was a modification of the American Thoracic Society standardized questionnaire with questions on dermal health taken from a previous UBC study. Workers were grouped in exposure categories and symptoms analysed using logistic regression. Metals were measured by ICP/MS on post shift hand wipes, full shift air sample filters, in whole blood, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post shift hand wipes and on bulk seedling samples. Using nursery pesticide application records, analyses focused on known pesticides applied to the seedlings at the study sites. Carbamate pesticides were analyzed by HPLC/MS and other pesticides by GC/MS. No evidence was found that tree planters who work with fertilizer are at an elevated risk of exposure to arsenic, lead, cadmium, chromium and nickel relative to other tree planters. Pesticide residues were found on seedlings taken from coastal work sites in April 2007. At coastal worksites the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37 – 106.3 ng.cm² and 0.48 – 15.9 ng/cm² respectively). Work with fertilizer was linked with an increased risk of cough, phlegm, nasal symptoms, nose bleed, and skin irritation. Hygiene conditions at tree planting work sites are very poor. Although measured exposures were low, hygiene conditions should improve to reduce the risk of health symptoms among tree planters. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate
37

Planting date and fertilizer effects on vegetable and cut flower production in high tunnels in Mississippi

Zhao, Yan 06 August 2011 (has links)
High tunnels have been used for many years worldwide. However, there has been limited research about use of high tunnel technology in the southeastern United States and its popularity has recently increased in Mississippi. A planting date study of 'Roma'' tomato, 'Legend' tomato, 'Ichiban' eggplant, 'Sweet Banana' pepper, ‘Benary’s Giant’ zinnia and ‘Potomac Red’ snapdragon was conducted in spring 2010 in three high tunnels in Starkville, Mississippi. Results showed for most cultivars (tomatoes, eggplant and pepper) a 12 Mar. 2010 planting date did not differ in marketable yield from planting on 2 Apr. 2010. In 2011, a fertilizer study on Encore lettuce mix and Ovation green mix was conducted both in high tunnel and in the field. Results indicated there was no effect of vermicompost tea or fertilizer treatments on yields of salad mixes.
38

Pond Management Approaches and Effects on Trophic Dynamics

Sherman, Michael Scott 15 December 2012 (has links)
Mississippi has an abundance of ponds which provides a number of opportunities for anglers. Several enhancement strategies are used to improve fish production in ponds, including fertilizing and supplemental feeding. These strategies may ignore the potential ecological impacts that may unexpectedly arise, such as prolific plant growth. This study consists of two phases; first, a mesocosm experiment investigating fertilizer application rates (mg P/L) in relation to potential sunfish growth, and second, a replicated pond experiment consisting of four treatments to simulate commonly used enhancement strategies. Mesocosm experiment showed a peak of sunfish growth at the 0.6 mg P/L level and served as a high fertilizer threshold level in pond experiment. Ponds were surveyed to assess treatment effects on each trophic level. The costs associated with each pond management strategy were documented. Results from this research help refine management recommendations to maximize results while minimizing costs to landowners and ecosystems.
39

THE EFFECT OF NITROGEN APPLICATION TIMING ON PLANT AVAILABLE PHOSPHORUS

Horner, Emily Renee 24 June 2008 (has links)
No description available.
40

Factors affecting ammonia volatilization from sewage sludge applied to soil in a laboratory study /

Donovan, William Cullen January 1982 (has links)
No description available.

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