• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 108
  • 85
  • 40
  • 8
  • 6
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 1
  • Tagged with
  • 328
  • 84
  • 55
  • 44
  • 34
  • 33
  • 33
  • 22
  • 21
  • 20
  • 19
  • 19
  • 18
  • 16
  • 16
  • 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.
41

Management of Ultra Narrow Row Cotton

Delaney, Dennis Patrick, Monks, C. Dale. January 2006 (has links) (PDF)
Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
42

The effect of plant spacing within a row on the competitive ability of soybean genotypes

Lin, Chuang-Sheng, January 1968 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
43

Effects of fertilizers and spacing of trees on cone production in young black spruce (Picea mariana (Mill.) B.S.P.) plantations

Smith, Ronald Frank. January 1983 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 66-74).
44

Características agronômicas do milho sob diferentes arranjos espaciais e densidades de plantas em região de cerrado /

Ferreira, João Paulo. January 2012 (has links)
Orientador: Ricardo Antonio Ferreira Rodrigues / Banca: Orivaldo Arf / Banca: Aguinaldo Jose Freitas Leal / Resumo: A redução no espaçamento entre linhas e a adoção de maiores densidades de plantas de milho, tem sido alvo de estudo por muitos pesquisadores, tendo em vista que os novos genótipos introduzidos no mercado são mais produtivos, com arquitetura de plantas de porte mais baixo e folhas eretas, apresentando melhor aproveitamento dos fatores ambientais como luz, água e nutrientes, proporcionando um possível aumento de rendimento da cultura. O trabalho foi desenvolvido no município de Selvíria - MS, em Latossolo Vermelho Distrófico álico, textura argilosa. O delineamento experimental foi em blocos casualizados, com quatro repetições, em esquema fatorial (5x2x2), sendo cinco populações (40.000; 55.000; 70.000; 85.000 e 100.000 plantas ha-1) e dois espaçamentos entre linhas (45 e 90 cm) e dois preparo de solo (sistema plantio direto e convencional), sendo utilizado milho híbrido. Não houve efeito significativo para a maioria das características agronômicas avaliadas em relação ao espaçamento de 45 e 90 cm entre linha. Houve diferença no Índice de área em função do sistema de preparo e espaçamento entre linhas em ambos os estádios (V-6 e V-T). Em relação ao rendimento de grãos, não foi verificado diferença significativa pelo fator espaçamento entre linhas de 45 e 90 cm. Contudo, houve efeito de regressão para o incremento da população, havendo maior rendimento na população de 100.000 plantas ha-1, com produtividade 10.410 kg ha-1 / Abstract:The reduction in row spacing and the adoption of the highest densities of plants has been the subject of study by many researchers, given that the new genotypes introduced to the market are more productive, with architecture of plants and lower-sized upright leaves, with greater use environmental factors of light, water and nutrients, justifying a possible increase in crop yield. The study was conducted in of Selvíria-MS Brazil, in alic Dystrophic Red Latosol, clay texture. The experimental design was randomized blocks with four replications in a factorial scheme (5x2x2), with five populations (40,000, 55,000, 70,000, 85,000 and 100,000 plants ha-1) and two row spacings (45 and 90 cm) and two soil preparation (tillage and conventional), by using the hybrid corn. No significant effects for most traits evaluated in relation to the spacing of 45 and 90 cm between rows. There were differences in leaf area index in these characters analyzed in tillage and spacing in both stages (V-6and V-T). In relation to grain yield, there were no significant differences by a factor score of 45 and 90 cm between rows. However, there was regression effect to increase the population, with higher income in the population of 100.000 plants ha-1 with production of 10.410 kg ha-1 / Mestre
45

Efeito do espaçamento de plantio na biomassa do fuste de um clone híbrido interespecífico de Eucalyptus grandis e Eucalyptus urophylla /

Santos, Maria Dolores dos, 1986- January 2011 (has links)
Resumo : O uso de florestas de Eucalyptus tem se tornado cada vez mais expressivo no Brasil, sobretudo por conta da excelente produção em termos volumétricos por elas alcançada e pelas boas características da madeira obtida. Várias empresas do setor florestal estão em busca do aumento da produção de madeira por unidade de área, tentando identificar, nos regimes de manejo, a técnica que agrega mais fortemente qualidade ao produto final por eles gerado. Neste contexto, o presente trabalho foi desenvolvido buscando a identificação dos melhores espaçamentos de plantio para florestas clonais de um híbrido interespecífico de Eucalyptus grandis e Eucalyptus urophylla, de forma a maximizar a produção de biomassa do fuste por hectare, e como objetivos complementares analisar a influência do espaçamento de plantio no incremento anual em diâmetro, altura, área basal ao longo da idade, volume por árvore e por hectare, além do percentual de casca das árvores e densidade básica da madeira no último ano. Os dados foram disponibilizados pela empresa Duraflora S.A. e são provenientes de um teste clonal exploratório que visa o aumento da produtividade e melhoria da qualidade da matéria prima através do estudo de espaçamentos. O delineamento estatístico utilizado foi o sistemático com fator quantitativo contínuo, com 16 tratamentos e 40 repetições, considerando que a variação entre os tratamentos foi o espaçamento entre as árvores e a entrelinha possuía um espaçamento constante de três metros. Com este arranjo, o experimento possuiu espaçamentos variando de 1,50m2 de área vital por árvore (6.667 árvores por hectare) até 15,75m2 de área vital árvore (635 árvores por hectare). A altura e o diâmetro à altura do peito -DAP foram medidos aos 36, 48, 60 e 72 meses de idade, e somente no ultimo... (Resumo completo, clicar acesso eletrõnico abaixo) / Abstract: The use of forests of Eucalyptus has become each time more expressive in Brazil, over all on account of the excellent production in volumetric terms for them reached and the good characteristics of the gotten wood. Some companies of the forest sector are in search of the increase of the wooden production for unit of area, trying to identify, in regimes of handling, the technique that strong adds more quality to the end item for them generated. In this context, the present work was developed to search the bests plantations spacing for clonal forests of a interspecific hybrid of Eucalyptus grandis and Eucalyptus urophylla, to maximize the production of the stem biomass per hectare, and as a complementary objective to analyze the influence of the plantation spacing in the annual increment in diameter, height, stem volume and volume per hectare, basal area throughout the age, beyond the percentage of bark of the trees and basic density of the wood in the last year. The data came from the Duraflora Company and are proceeding from a clonal test exploration that aims at the increase of the productivity and improvement of the quality of the substance cousin through the study of plantations spacing. The used statistical delineation was the systematic with continuous quantitative factor, 16 treatments and 40 repetitions, considering that the variation between the treatments was only the spacing between the trees and the space between lines was a constant of 3 meters. With this arrangement, the vital area for tree was about 1,50m2 (6,667 trees per hectare) until 15,75m2 (635 trees per hectare). The trees height and the diameter breast height - DBH had been measured to the age of 36, 48, 60 and 72 months, and only in the last year three trees of each treatment had been sampled to... (Complete abstract click electronic access below) / Orientador: Adriano Wagner Ballarin / Coorientador: Luiz Alberto Blanco Jorge / Banca: José Nivaldo Garcia / Banca: Hernando Alfonso Lara Palma / Mestre
46

Características agronômicas do milho sob diferentes arranjos espaciais e densidades de plantas em região de cerrado

Ferreira, João Paulo [UNESP] 23 February 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-23Bitstream added on 2014-06-13T19:39:04Z : No. of bitstreams: 1 ferreira_jp_me_ilha.pdf: 708856 bytes, checksum: 2cdf06bc163372312c3583d2575778f7 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A redução no espaçamento entre linhas e a adoção de maiores densidades de plantas de milho, tem sido alvo de estudo por muitos pesquisadores, tendo em vista que os novos genótipos introduzidos no mercado são mais produtivos, com arquitetura de plantas de porte mais baixo e folhas eretas, apresentando melhor aproveitamento dos fatores ambientais como luz, água e nutrientes, proporcionando um possível aumento de rendimento da cultura. O trabalho foi desenvolvido no município de Selvíria – MS, em Latossolo Vermelho Distrófico álico, textura argilosa. O delineamento experimental foi em blocos casualizados, com quatro repetições, em esquema fatorial (5x2x2), sendo cinco populações (40.000; 55.000; 70.000; 85.000 e 100.000 plantas ha-1) e dois espaçamentos entre linhas (45 e 90 cm) e dois preparo de solo (sistema plantio direto e convencional), sendo utilizado milho híbrido. Não houve efeito significativo para a maioria das características agronômicas avaliadas em relação ao espaçamento de 45 e 90 cm entre linha. Houve diferença no Índice de área em função do sistema de preparo e espaçamento entre linhas em ambos os estádios (V-6 e V-T). Em relação ao rendimento de grãos, não foi verificado diferença significativa pelo fator espaçamento entre linhas de 45 e 90 cm. Contudo, houve efeito de regressão para o incremento da população, havendo maior rendimento na população de 100.000 plantas ha-1, com produtividade 10.410 kg ha-1 / The reduction in row spacing and the adoption of the highest densities of plants has been the subject of study by many researchers, given that the new genotypes introduced to the market are more productive, with architecture of plants and lower-sized upright leaves, with greater use environmental factors of light, water and nutrients, justifying a possible increase in crop yield. The study was conducted in of Selvíria-MS Brazil, in alic Dystrophic Red Latosol, clay texture. The experimental design was randomized blocks with four replications in a factorial scheme (5x2x2), with five populations (40,000, 55,000, 70,000, 85,000 and 100,000 plants ha-1) and two row spacings (45 and 90 cm) and two soil preparation (tillage and conventional), by using the hybrid corn. No significant effects for most traits evaluated in relation to the spacing of 45 and 90 cm between rows. There were differences in leaf area index in these characters analyzed in tillage and spacing in both stages (V-6and V-T). In relation to grain yield, there were no significant differences by a factor score of 45 and 90 cm between rows. However, there was regression effect to increase the population, with higher income in the population of 100.000 plants ha-1 with production of 10.410 kg ha-1
47

Efeito do espaçamento de plantio na biomassa do fuste de um clone híbrido interespecífico de Eucalyptus grandis e Eucalyptus urophylla

Santos, Maria Dolores dos [UNESP] 25 August 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-25Bitstream added on 2014-06-13T19:19:02Z : No. of bitstreams: 1 santos_md_me_botfca.pdf: 2278704 bytes, checksum: 8b089e60925e4ff1a31aa9f4f65e2eb1 (MD5) / O uso de florestas de Eucalyptus tem se tornado cada vez mais expressivo no Brasil, sobretudo por conta da excelente produção em termos volumétricos por elas alcançada e pelas boas características da madeira obtida. Várias empresas do setor florestal estão em busca do aumento da produção de madeira por unidade de área, tentando identificar, nos regimes de manejo, a técnica que agrega mais fortemente qualidade ao produto final por eles gerado. Neste contexto, o presente trabalho foi desenvolvido buscando a identificação dos melhores espaçamentos de plantio para florestas clonais de um híbrido interespecífico de Eucalyptus grandis e Eucalyptus urophylla, de forma a maximizar a produção de biomassa do fuste por hectare, e como objetivos complementares analisar a influência do espaçamento de plantio no incremento anual em diâmetro, altura, área basal ao longo da idade, volume por árvore e por hectare, além do percentual de casca das árvores e densidade básica da madeira no último ano. Os dados foram disponibilizados pela empresa Duraflora S.A. e são provenientes de um teste clonal exploratório que visa o aumento da produtividade e melhoria da qualidade da matéria prima através do estudo de espaçamentos. O delineamento estatístico utilizado foi o sistemático com fator quantitativo contínuo, com 16 tratamentos e 40 repetições, considerando que a variação entre os tratamentos foi o espaçamento entre as árvores e a entrelinha possuía um espaçamento constante de três metros. Com este arranjo, o experimento possuiu espaçamentos variando de 1,50m2 de área vital por árvore (6.667 árvores por hectare) até 15,75m2 de área vital árvore (635 árvores por hectare). A altura e o diâmetro à altura do peito -DAP foram medidos aos 36, 48, 60 e 72 meses de idade, e somente no ultimo... / The use of forests of Eucalyptus has become each time more expressive in Brazil, over all on account of the excellent production in volumetric terms for them reached and the good characteristics of the gotten wood. Some companies of the forest sector are in search of the increase of the wooden production for unit of area, trying to identify, in regimes of handling, the technique that strong adds more quality to the end item for them generated. In this context, the present work was developed to search the bests plantations spacing for clonal forests of a interspecific hybrid of Eucalyptus grandis and Eucalyptus urophylla, to maximize the production of the stem biomass per hectare, and as a complementary objective to analyze the influence of the plantation spacing in the annual increment in diameter, height, stem volume and volume per hectare, basal area throughout the age, beyond the percentage of bark of the trees and basic density of the wood in the last year. The data came from the Duraflora Company and are proceeding from a clonal test exploration that aims at the increase of the productivity and improvement of the quality of the substance cousin through the study of plantations spacing. The used statistical delineation was the systematic with continuous quantitative factor, 16 treatments and 40 repetitions, considering that the variation between the treatments was only the spacing between the trees and the space between lines was a constant of 3 meters. With this arrangement, the vital area for tree was about 1,50m2 (6,667 trees per hectare) until 15,75m2 (635 trees per hectare). The trees height and the diameter breast height - DBH had been measured to the age of 36, 48, 60 and 72 months, and only in the last year three trees of each treatment had been sampled to... (Complete abstract click electronic access below)
48

Effects of Season, Spacing and Intensity of Seeding on Emergence and Survival of Four Wheatgrass Species in Central Utah

Abbott, Edwin B. 01 January 1953 (has links)
No description available.
49

LONG-TERM EFFECTS OF SUBSURFACE DRAIN SPACING ON SOIL PHYSICAL AND CHEMICAL PROPERTIES

Kevin Samuel Mitchell (9173993) 27 July 2020 (has links)
<p><a>Subsurface tile drainage is a commonly used practice to lower the water table in poorly drained soils, and is often done to improve soil conditions for agricultural operations. Tile drainage has been shown to increase cash crop yield, allow for more timely field operations, and reduce erosion.</a> However, few studies have evaluated the potential long-term changes in soil physical and chemical properties as a result of subsurface tile drainage. This study was conducted on a naturally poorly drained Clermont silt loam soil located at the Southeast Purdue Ag Center near Butlerville Indiana. The intent of this study was to characterize possible evolution of soil physical and chemical properties after 35 years of subsurface drainage. <a>The field site was established in the spring of 1983 with tile drains installed in 2 blocks with tile spacings of 5, 10, 20, and 40m, with the 40-m spacing used as the undrained control</a>. Soil samples were collected in May of 2018 to a depth of 1 meter and were analyzed for carbon and nitrogen content, aggregate stability, and fertility at depth increments of 0-5, 5-15, 15-30, 30-50, 50-75 and 75-100cm. In-field measurements were also taken in May of 2018 for vane shear resistance and in May of 2019 for cone penetration resistance. Total carbon content was found to be significantly higher in the 5-m tile spacing than the 40-m tile spacing in the 0-5cm and 5-15cm depths, with the 10-m and 20-m tile spacings being intermediate. Conversely, in the 75-100cm depth the inverse trend was observed, where the 40-m tile spacing was found to have significantly greater carbon content than narrower tile spacings. Trends observed with carbon stocks per depth increment closely followed trends observed with carbon content at the same depth. However, no significant differences were observed among treatments with the summation of carbon stocks to the 1-m depth. Tile spacing did not have a significant effect on aggregate stability at any depth. The soil fertility data showed some indication of the potential translocation of soil calcium from the soil surface to lower depths in the soil profile resulting in significantly higher soil pH in the 5-m tile spacing than the 40-m tile spacing in all depths below 30cm. No consistent differences related to treatment were found with the cone penetrometer or vane shear penetrometer measurements. After 35 years of drainage history, tile drain spacing did not have a significant effect on total carbon stocks to the 1-m depth, but rather seems to have had a significant effect on the vertical distribution of soil carbon content throughout the soil profile.</p>
50

Influences Of Artificial Reefs On Juvenile Red Snapper Along The Mississippi Gulf Coast

Brandt, Jason Robert 10 December 2010 (has links)
Artificial reefs are important management tools for red snapper, Lutjanus campechanus, fisheries in the Northern Gulf of Mexico. I deployed fish traps (0.97 m long; 0.64 m height; 175 x 115 mm funnel mouth size) to collect red snapper < 406 mm total length (TL) associated with pyramid-shaped artificial reef structures (3.7 m triangular base; 2.4 m height; 3.2 metric tons) to evaluate two reef distribution designs: (1) five closely-spaced pyramid units, and (2) five closely-spaced pyramids with two sets of two pyramids at 30.5, 61.0, and 91.5 m from the five pyramids. In 26 sampling trips, 927 red snapper were captured. Catch per unit effort (fish/hour) did not differ significantly among patterns (P= 0.396). Red snapper lengths differed significantly among patterns (P= 0.005), with the largest mean total length (235 mm, SE= 5.14) occurring at the pattern with 61.0-m spacing.

Page generated in 0.0441 seconds