Thesis (M.S.) in Plant, Soil and Environmental Sciences--University of Maine, 2008. / Includes vita. Includes bibliographical references (leaves 112-118).

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Faced with the twin challenges of food security and environmental protection, given the energy resource scarcity, agriculture needs to develop production systems that are highly productive, economically viable and environmentally sound. In this regard, several production systems have been recently developed. All of them share the general objective of using less energy per unit of output. / The focus of this study for red pepper, is to examine the environmental performance of a plasticulture system compared to a conventional system in terms of: (1) energy inputs per unit of output; and (2) cost per unit of output. / Energy analysis was performed to account for the total energy consumed in red pepper production under silver mulch and no-mulch. The method of process analysis was employed to account for total energy requirements for different inputs. Partial budgets for both type of production systems were constructed to estimate the costs of production. The analysis boundary was set at the farm gate. Production costs are derived from secondary data. Data on mulch yield were based on the results of an experimental trail conducted on the farm of Macdonald Campus of McGill University in the West Island of Montreal (Fava, 1996). (Abstract shortened by UMI.)

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Two independent experiments were conducted during 1992 and 1993 using a Randomized Complete Block Design with four replications. The first experiment was designed to study the effect of mulch spectral properties on weed growth and development. The second was conducted to study the effect of polyethylene mulch on aphid population and on growth and yield of bell pepper. Initially, rye-grass germination under polyethylene mulches was significantly higher than that on bare soil, whereas mustard seed germination under mulches did not differ significantly from that on bare soil. However, at the end of 30 days, none of these weeds were observed in the mulched plots. Transmittance, reflectance, and absorbance were recorded in the Near Ultraviolet (390-399 nanometre), Photosynthetically Active Radiation (400-700 nanometre), and Near Infrared (701-1100 nanometre) bands for black, black microperforated, wavelength selective and silver mulches. Aging had little effect on the optical properties of the mulches. The wavelength selective (Infra red transmitting = IRT-76) green mulch had the warmest mean soil temperatures, followed by silver, black, microperforated black mulch, and bare soil. The soil moisture content was higher under plastic mulches than in bare soil. The use of mulches significantly increased both the early and total marketable yields of pepper. Plants grown with polyethylene mulch had significantly lower number of aphids on them than did their bare soil counterparts.

Written for the Dept. of Plant Science. Title from title page of PDF (viewed 2009/06/10). Includes bibliographical references.

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Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Mar. 6, 2009). Thesis advisor: Brian Leib. Vita. Includes bibliographical references.

Lettuce plants (Lactuca sativa L. var. Ithaca) were transplanted on different beige and black paper mulches and on a coextruded white/black polyethylene mulch in organic soil in 1997 and 1998. Non-weeded and weeded control plots were also used. Plant mortality in 1997 for plants grown on bare soil was 10 to 15% greater than that of mulched plants. Head weight was found to be 3.6 times (1997) and 12 times (1998) greater for lettuce grown on mulch compared with a weeded control. The transmission, reflection and absorption of light of the white/black polyethylene mulch and black paper mulch remained stable over the course of the experiment while those of the other papers changed over time. Paper mulch decomposition occurred during the experiment. Although, black paper mulch was the only mulch that gave complete control of weed growth, weed populations present under the beige papers were too small in terms of the size and number of weeds to cause lettuce yield reduction.

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