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.)

Thesis (M.S. - Plant Sciences)--University of Arizona. / Includes bibliographical references (leaves 90-92).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 42-45). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 27-32). Also available via the Internet.

No description available.

Call number: LD2668 .T4 1961 W34

Made available in DSpace on 2014-06-11T19:22:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-02-05Bitstream added on 2014-06-13T20:48:38Z : No. of bitstreams: 1 maciel_cdg_me_botfca.pdf: 520733 bytes, checksum: a0940e67eb688e6073b518edf88cf6c1 (MD5) / O presente trabalho teve como objetivos a quantificação da produção de biomassa seca das principais palhadas utilizadas como cobertura morta em sistemas de plantio direto, nos Estados do Paraná e Mato Grosso do Sul, bem como a avaliação das dinâmicas de molhamento e o comportamento de um traçante (simulando herbicidas), em diferentes coberturas mortas. No levantamento de biomassa foram amostrados os resíduos culturais de cevada (Hordeum vulgare L.), azevém (Lolium multiflorum), trigo (Triticum aestivum), aveias colhida e rolada (A. strigosa Schieb), milho (Zea mays), milheto (Penisetum americanum) e capim-braquiária (Brachiaria decumbens Stapf). As frequências acumuladas dos dados originais forma adequadamente ajustados segundo modelo de Gompertz, apresentando elevada precisão (Rø > 0,9873). Os restos culturais de milho e trigo apresentaram a maior e menor uniformidades de distribuição do peso de matéria seca, respectivamente. Os estudos de dinâmica de molhamento e recuperação do corante FDC-1 foram desenvolvidos através de simulação de chuva artificial sobre 3000, 6000 e 9000 Kg de matéria seca ha elevado a -1, utilizando sete tipos de palhas. Destacam-se em, ambos os casos, o ajuste adequado dos dados originais ao modelo de Mitscherlich (Rø > 0,9064 e > 0,9758). Os resultados indicam uma tendência de uniformização na retenção da água das chuva entre os diferentes tipos de palhadas, com o aumento da quantidade de cobertura utilizada. A formação de pontos secos associados a canais preferenciais de escorrimento, induzem a menor capacidade de embebição e retenção da água das chuvas pelas palhadas. As quantidades totais do corante FDC-1 que atingiram o solo foram relativamente uniformes, após precipitações entre 10 e 20 mm, independente do tipo e quantidade de palha, indicando que ambas características pouco interferem na capacidade do traçante em transpor a cobertura morta. / The presente work had as objectives to quantify the production of dry cultural residues of the man straws used as mulches in no-till systems, in the State of Paraná and Mato Grosso do Sul, as well as, to evaluate the wetting dynamic and the behavior of a dye (simulating herbicides), in different cultural residues. In the biomass survey it were evaluated the cultural residues (Kg of dry matter ha raised -1) of barley (Hordeum vulgare L.), perennial ryegrass (Lolium multiflorum), wheat (Triticum aestivum), harvested oat (Avena strigosa Schieb), rolled oat (Avena strigosa Schieb), corn (Zea mays), millet (Penisetum americanum) and braquiária grass (Brachiaria decumbens Stapf). The acumullated frequencies of the original data fitted well to the Gompertz model (Rø > 0,9064 e > 0,9758). The most and least uniform distribution of the cultural residues in the field were observed for corn and wheat respectivelly. The studies of the wetting dynamic and recovery of the dye FDC-1 were developed through simulation of artificial rain on 3000, 6000 and 9000 Kg of dry matter ha raised -1 of seven types of straws. The data fitted well to the Mitscherlich (Rø > 0,9064 and > 0,9758). The results indicated an uniformity tendency in the retention of the rain water among the different types of straws, with the increase of th amont of mulch. The formation fo dry points associated to preferential channels of running off, reduces the capacity of absorption and retention of the rain water by the straws. The total amounts of the dye FDC-1 that reached the soil were relatively uniform, after precipitations between 10 and 20 mm, independt of the type and amount of straw, indicating that both characteristics have minimum efects in the capacity of the dye in transporting the straw.

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.

Two field studies examining direct ecological weed control practices were conducted in Lexington, Kentucky. The first evaluated weed control efficacy and influence on yields of several mulches in two organically-managed bell pepper (Capsicum annum) production systems for two years. Peppers were planted in double rows in flat, bare ground or on black polyethylene-covered raised beds with drip irrigation, and four mulches (straw, compost, wood chips, and undersown white dutch clover (Trifolium repens L.) living mulch) were applied to the two production systems. In both years, polyethylene-covered raised beds produced higher yields than the flat, bare ground system. In the second year, the polyethylene-covered bed system coupled with mulching in-between beds with compost or wood chips after cultivation provided excellent weed control and yields. The second field study evaluated the efficacy of soil solarization and shallow cultivation on the invasive and noxious weed johnsongrass over two years (Sorghum halapense). A soil solarization treatment, using clear plastic stretched over soil for eight weeks, and a cultivated bare fallow treatment, utilizing a tractor pulled cultivator implement equipped with sweep blades, were randomly applied during the summers of 2003 and 2004 to a field infested with johnsongrass. Solarized and cultivated plots in both years were lightly tilled 8 months after completion of the initial treatment period. At the conclusion of the experiment the johnsongrass population was significantly reduced in all treatments and in the control plots compared to the original infestation. These two experiments testing direct weed control practices (mulching, cultivation, solarization) were undertaken in the context of an ecological weed management plan that includes long term strategies to reduce weed infestations such as crop rotation, cover cropping, and fertility management that are essential for organic farmers.

Thesis (MEng (MechEng))--University of South Australia, 1999