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Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-03Bitstream added on 2014-06-13T20:48:35Z : No. of bitstreams: 1 furtado_mb_me_botfca.pdf: 393078 bytes, checksum: def48bccd2c07da6fc33ce1966be2848 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cultura do milho constitui um dos principais insumos para o segmento produtivo, porém, a sua produtividade é considerada baixa devido a inúmeros fatores que ainda precisam ser estudados, dentro os quais pode-se citar materiais genéticos adequados a cada região, densidade de semeadura, manejo do solo, dentre outros. Assim, com o objetivo de avaliar o desempenho de cultivares de milho com composições genéticas distintas, cultivadas em espaçamento reduzido, com variação no número de plantas por unidade de área, em sistemas de preparo de solo que variaram a intensidade e a profundidade de mobilização, realizou-se a presente pesquisa. O experimento foi desenvolvido na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas/UNESP-Campus de Botucatu, no ano agrícola de 2003/2004. O delineamento experimental utilizado foi o de parcela sub-subdividida, com 8x2x3 e quatro repetições, sendo os fatores de variações oito maneiras de preparo de solo, dois cultivares de milho e três populações de plantas. Os tratamentos com preparo de solo utilizados foram: T1- plantio direto em todas as safras; T2- arado de disco em todas as safras, trabalhando à profundidade de 0,20 a 0,25 m; T3- grade pesada em todas as safras, trabalhando à profundidade de 0,15 a 0,18 m; T4- escarificador em todas as safras, trabalhando à profundidade de 0,35 m; T5- arado de disco em duas safras sendo o escarificador na terceira safra, trabalhando à profundidade de 0,20 a 0,25 m; e T6- grade pesada em duas safras e arado de disco na terceira safra, T7- grade pesada em duas safras e escarificador na terceira safra, e T8- grade pesada na primeira safra, escarificador na segunda e arado de disco na terceira safra. O preparo secundário do solo foi feito com a passagem por duas vezes de grade niveladora trabalhando à profundidade de 0,10 a 0,13 m em todos os tratamentos, excetuando-se o plantio direto... / The corn crop is one of the mail materials to the productive segment. However, the productivity is considered low due to many different factors which need to be better studied, like genetic materials appropriated to each region, density sowing, soil tillage, among others. The objective of this study was the evaluation of the performance with corn cultivars a different genetic composition. These plants were planted in a reduced row width , with a variation in number of plants number by unit of area, in soil tillage systems that changed both the intensity and the deph of mobilization. The experiment was carried out in the Experimental Lageado Farm of the Agronomic Science College, UNESP-Botucatu-SP in 2003/2004. The experimental design used was the randomized blocks in split-splitplot, with 8x2x3 and four repetitions. The variation factors were 8 ways soil evaluation, two corn cultivars and three plant populations. The treatment with soil tillage used were:T1-no tillage in every harvest; T2-disc plowing in every harvest, working in depth of 0,20 to 0,25 m; T3- heavy harrowing in every harvest ,working in depth of 0,15 to 0,18 m; T4- chisel plow in every harvest, working in depth of 0,35 m; T5- disc plowing in twice harvest and chisel plow in the third, working in depth of 0,20 to 0,25 m; T6- heavy harrowing in twice harvest and disc plowing in the third; T7- heavy harrowing in twice harvest and chisel plow in the third, and T8- heavy harrowing in the first harvest, chisel plow in the second and disc plowing in the third, working in depth of 0,15 to 0,18 m. The secondary soil tillage was done passing the material twice by the level harrowing working in depth of 0, 10 to 0,13 m in every treatment, except the no tillage. The corn cultivars used were: The hybrid AG9010 and the variety AL34 and the populations were of 50000, 70000 and 100.000 plants.ha-1...(Complete abstract click electronic access below)

Studies were conducted in 2011 and 2012 to determine if narrow row corn (Zea mays L.) and/or greater plant populations could affect yield, time to silking, and other physiological characteristics. Main plots of six hybrids were arranged as a randomized complete bock design with three replications. Split plots were row widths of 76-cm (wide rows) and 20-cm rows on 76-cm spacing (twin rows). Split-split plots were target plant populations of 75 000 and 111 000 plants ha-1. Corn was no-till seeded into soybean stubble near Lexington, KY in 2011 and 2012. Year interacted with most factors analyzed in the study. This was expected, given the extreme differences in weather. 2011 ASI (days) approached zero as plant population increased in wide rows in two out of four hybrids. ASI response to plant population in twin rows was not significant for any hybrid. In 2011, yield was greater in twin rows than wide rows. For significant equations, in 2011 grain yield increased as plant population increased, but in 2012 grain yield decreased as plant population increased, across both row widths. Kernel number per ear decreased as plant population increased in 2011 and 2012, but at different rates for wide and twin rows.

Corn (Zea mays L.) defoliation experiments have been conducted for more than 120 years. However, there is limited data on the effect of row width on defoliation in modern hybrids. A two-year experiment was conducted in Lexington, Kentucky with two hybrids (113 relative maturity (RM) and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7-100%, V14-50%, V14-100%, R2-50% and R2-100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38-cm rows than 76-cm rows in 2012. For 2013, corn yield for 38-cm was 10% greater, but hybrid, row width and defoliation interacted. Lowest yields were caused by V14-100% followed by R2-100%. Defoliations of V14-50% and R2-50% reduced yields in some cases. Complete defoliations at V7 did not reduce yields in most comparisons. Light interception below 80% during the critical period was enough to attain maximum yields in defoliated plants. Kernel number and kernel weight were most reduced by V14-100% and R2-100% defoliations, respectively. There is a potential for narrow rows to reduce grain yield losses after a defoliation event, when compared with wide rows.

Corn (Zea mays L.) hectarage has increased rapidly in Utah and Idaho in recent years due to expansion of the dairy industry, but little is known about corn production practices that optimize yield and quality of silage corn in semi-arid irrigated cropping systems. The objective of this study was to determine the dry matter yield and quality effects of corn hybrids grown in different plant densities and row widths in the Intermountain West. Field experiments were conducted under irrigation in 2015 and 2016 at locations near North Logan, Utah and Jerome, Idaho. The experimental design was a randomized complete block in a split-split plot arrangement with four replications. The whole plot treatment was hybrid (DKC 49-29, DKC 56-54, and DKC 61-88), the sub-plot treatment was row width (76 and 51-cm), and the sub-sub plot treatment was plant density (61,776 to 123,552 plants ha-1 at intervals of 12,355 plants ha-1). The 51-cm row width resulted in forage dry matter yield increases of 4-7% over corn in 76-cm rows. Hybrids differed in response to row width, with no difference detected for the 99-RM hybrid but a significant yield increase for the 106- and 111-RM hybrids by planting in narrow rows. Yield increased quadratically as plant population increased from 61,776 to 123,552 plants ha-1 for all hybrids. The only forage nutritive value that was influenced by row spacing was crude protein (CP), where the 76-cm row spacing showed a 4.5% advantage over the 51-cm row width. Starch increased approximately 3% from the lowest to highest plant densities tested. Net returns showed possible positive increases when comparing row width adjustments. Silage corn yield and quality in the Intermountain West appears to be optimized in 51-cm rows at a plant population between 86,487 and 98,842 plants ha-1.

The United States share of the exported flue-cured tobacco market has decreased over the last decade as other countries have increased production of improved quality tobacco. Such tobacco is available at a substantially lower price than U. S. tobacco and thus desirable for the manufacture of less expensive discount cigarettes. Although world consumption of American style cigarettes is increasing, demand is not sufficient to maintain current production levels of premium quality U. S. flue-cured tobacco. Production systems that increase yields of suitable quality tobacco for discount cigarette manufacture without increasing production costs would allow tobacco to be offered competitively on the world market while maintaining current income. A study of ten management systems was conducted evaluating the influence of plant spacing, topping height, and harvest method on yield and quality of flue-cured tobacco. Leaf populations of 538,000/ha harvested once-over resulted in a 6.5%, 11.0%, 6.0%, and 13.5% increase in yield, value, price, and grade index, respectively, compared to the standard treatment. An expert panel showed no preference among systems and judged all systems acceptable in quality. A study conducted as a randomized complete block in a split plot arrangement evaluated the influence of row spacing and plant spacing on the yield and quality of flue-cured tobacco harvested once-over. Yield, value, and grade index increased while price per kg was unchanged as plant population increased. Flue-cured tobacco harvested in a single harvest produced cured leaf of acceptable quality; however, increased leaf populations are required to maintain acceptable yields. / Master of Science

Orientador: Silvio José Bicudo / Banca: Cláudio Cavariani / Banca: Otávio Jorge G. Abi Saab / Resumo: A cultura do milho constitui um dos principais insumos para o segmento produtivo, porém, a sua produtividade é considerada baixa devido a inúmeros fatores que ainda precisam ser estudados, dentro os quais pode-se citar materiais genéticos adequados a cada região, densidade de semeadura, manejo do solo, dentre outros. Assim, com o objetivo de avaliar o desempenho de cultivares de milho com composições genéticas distintas, cultivadas em espaçamento reduzido, com variação no número de plantas por unidade de área, em sistemas de preparo de solo que variaram a intensidade e a profundidade de mobilização, realizou-se a presente pesquisa. O experimento foi desenvolvido na Fazenda Experimental Lageado da Faculdade de Ciências Agronômicas/UNESP-Campus de Botucatu, no ano agrícola de 2003/2004. O delineamento experimental utilizado foi o de parcela sub-subdividida, com 8x2x3 e quatro repetições, sendo os fatores de variações oito maneiras de preparo de solo, dois cultivares de milho e três populações de plantas. Os tratamentos com preparo de solo utilizados foram: T1- plantio direto em todas as safras; T2- arado de disco em todas as safras, trabalhando à profundidade de 0,20 a 0,25 m; T3- grade pesada em todas as safras, trabalhando à profundidade de 0,15 a 0,18 m; T4- escarificador em todas as safras, trabalhando à profundidade de 0,35 m; T5- arado de disco em duas safras sendo o escarificador na terceira safra, trabalhando à profundidade de 0,20 a 0,25 m; e T6- grade pesada em duas safras e arado de disco na terceira safra, T7- grade pesada em duas safras e escarificador na terceira safra, e T8- grade pesada na primeira safra, escarificador na segunda e arado de disco na terceira safra. O preparo secundário do solo foi feito com a passagem por duas vezes de grade niveladora trabalhando à profundidade de 0,10 a 0,13 m em todos os tratamentos, excetuando-se o plantio direto...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The corn crop is one of the mail materials to the productive segment. However, the productivity is considered low due to many different factors which need to be better studied, like genetic materials appropriated to each region, density sowing, soil tillage, among others. The objective of this study was the evaluation of the performance with corn cultivars a different genetic composition. These plants were planted in a reduced row width , with a variation in number of plants number by unit of area, in soil tillage systems that changed both the intensity and the deph of mobilization. The experiment was carried out in the Experimental Lageado Farm of the Agronomic Science College, UNESP-Botucatu-SP in 2003/2004. The experimental design used was the randomized blocks in split-splitplot, with 8x2x3 and four repetitions. The variation factors were 8 ways soil evaluation, two corn cultivars and three plant populations. The treatment with soil tillage used were:T1-no tillage in every harvest; T2-disc plowing in every harvest, working in depth of 0,20 to 0,25 m; T3- heavy harrowing in every harvest ,working in depth of 0,15 to 0,18 m; T4- chisel plow in every harvest, working in depth of 0,35 m; T5- disc plowing in twice harvest and chisel plow in the third, working in depth of 0,20 to 0,25 m; T6- heavy harrowing in twice harvest and disc plowing in the third; T7- heavy harrowing in twice harvest and chisel plow in the third, and T8- heavy harrowing in the first harvest, chisel plow in the second and disc plowing in the third, working in depth of 0,15 to 0,18 m. The secondary soil tillage was done passing the material twice by the level harrowing working in depth of 0, 10 to 0,13 m in every treatment, except the no tillage. The corn cultivars used were: The hybrid AG9010 and the variety AL34 and the populations were of 50000, 70000 and 100.000 plants.ha-1...(Complete abstract click electronic access below) / Mestre

Thesis (PhD(Agric) (Agronomy))--Stellenbosch University, 2008. / The adoption of the no-till planting method brought about changes to the way the wheat crop is established in the Mediterranean climate of the Western Cape. Row widths have to increase from the normal narrow rows (170-180 mm) to at least 250 mm to allow for sufficient stubble handling. Furthermore, planters are designed to place seed accurately in the soil at uniform depth, which may increase seedling survival rates. The main objective of this study was to determine the influence of the use of wide row widths on yield, the components of yield and grain quality parameters and to revisit planting density recommendations to be used with the notill planting method. On-farm, producer managed trials which included cultivars, row widths and planting density treatments were planted at Riversdale, Swellendam and Caledon in the Southern Cape region and at Moorreesburg and Hopefield in the Swartland during the 2004 to 2006 production seasons. All trials were factorial RCB designs with split-split plot arrangements. Grain yield, grain protein, hectolitre mass (HLM) and the yield components, seedlings m-2, seedling survival (%), number of heads m-2, number of heads plant-1, number of kernels head-1 and thousand kernel mass (TKM) were determined at all sites in 2005 and 2006. Seedling survival rates of 80% were easily achieved in all trials with the exception of Caledon and Swellendam in 2005. The no-till planting method may be efficient to improve on survival rates of 50-70% found with the conventional planting methods. The yield component response that raised the most concern was the clear trend of the reduction in the number of heads m-2 as row widths increased, which was significant in eight out of the nine experiments. The number of heads plant-1 decreased significantly as planting density increased in all experiments. Cultivars differed in the grain quality parameters grain protein (%) and HLM but were influenced minimally by the other treatments. Reductions in grain yield occurred in three out of eight trials in the Southern Cape and in three out of six trials in the Swartland, with reductions of between 6.8% and 33% in some seasons. The risk of yield loss due to wide row widths could not be excluded by this study and therefore the row widths used by producers should remain as narrow as practically possible. Grain yield response to increasing planting density differed between the two regions. No significant yield benefits were found in any of these trials if planting densities were increased above 175 target plants m-2. Planting densities may be reduced to between 70 and 87.5 kg seed ha-1 to achieve this target if the crop is planted in time and seedling survival rates of at least 80% can be achieved.