A produção de batata no Brasil é migratória, devido à alta ocorrência de doenças de solo onde seu cultivo é realizado anualmente após a cultura do milho (Zea mays) e o preparo de solo é feito com grade aradora, implemento cujo uso freqüente estabelece impedimentos físicos. O presente trabalho avaliou um sistema de preparo profundo de solo associado ao cultivo de três diferentes gramíneas Panicum maximum cv. Tanzânia, Brachiaria brizantha cv. Marandu e milho híbrido Dekalb 191 quanto a sua capacidade de promover melhores condições físicas de solo, assim como sua influência sobre a produtividade e ocorrência de doenças na cultura da batata. O preparo de solo alternativo foi capaz de promover melhores condições físicas de solo e, mesmo após dois ciclos da sucessão de culturas, não houve influência da espécie de gramínea utilizada sobre os parâmetros avaliados, embora essas plantas tenham apresentado características diferentes quanto à produção de raízes e de parte aérea. As melhores condições físicas de solo foram responsáveis pelo aumento da produtividade e da qualidade de tubérculos, obtido com o preparo profundo de solo, mas não influenciou a ocorrência de doenças e de outros danos aos tubérculos. A incidência de doenças em geral foi baixa e isso indica que um trabalho com maior número de ciclos da sucessão de culturas seria necessário para testar a hipótese de que o sistema de preparo de solo e sucessão de culturas avaliado descartaria a necessidade de migração na cultura da batata. / Potato crop migrates continually in Brazil, due to the high incidence of soil diseases where potato is cultivated every year after a maize (Zea mays) crop cycle and when chisel plough, which causes sub-superficial compaction, is used for soil management. This work evaluated a soil deep tillage system associated to three different grasses, Panicum maximum cv. Tanzânia, Brachiaria brizantha cv. Marandu and maize Dekalb 191 in order to improve soil physical conditions and to reduce potato soil diseases incidence. The soil deep tillage system improved soil physical conditions and, although the evaluated grasses presented different characteristics of root and shoot production, the grass specie did not influence the evaluated soil parameters and potato productivity after two years of research. The soil physical improvement promoted higher potato yield and quality in the soil deep tillage system but did not influence diseases incidence and other damages to the tubers, assessed after harvesting. The average disease incidence was low, which meant a longer term work was necessary to show if the soil deep tillage system associated to grasses would avoid the Brazilian potato crop migration.

O presente estudo objetivou a análise, em lavouras sob semeadura direta, da distribuição vertical e horizontal da resistência à penetração medida por valores georreferênciados do Índice de Cone (IC) e a influência do teor de água do solo, permitindo assim a interpolação para análise de relações causa e efeito. Fatores importantes como o teor de argila, silte, densidade, espaço poroso e teor de matéria orgânica do solo também foram monitorados. Utilizou-se um penetrômetro hidráulico eletrônico, receptores de GPS, amostradores de solo e programas computacionais para o tratamento e obtenção dos resultados em três áreas de estudo sob semeadura direta. Os resultados foram apresentados na forma de mapas em diferentes profundidades, os quais permitem a visualização da espacialidade dos atributos, e pela regressão entre os dados interpolados através da função que apresentou o coeficiente de determinação (R2) mais elevado. Constatou-se a ocorrência de valores maiores para o IC nas profundidades compreendidas de 0,1 a 0,2 m em todas as áreas estudadas. Observou-se também valores menores de IC em locais com maior teor de matéria orgânica, a qual coincidiu com maiores teores de argila e silte em uma das áreas para a qual estes três atributos foram monitorados. A visualização das relações entre fatores nos mapas e a regressão adequada entre os valores interpolados dos atributos destes nem sempre foram possíveis, mas quando houve esta possibilidade, a inter-relação entre o IC e o teor de água, assim como todas as relações espaciais com os demais atributos do solo estudados foram visíveis nos mapas e constatáveis pelo modelo ajustado. O IC foi influenciado principalmente pelo teor de água, densidade e espaço poroso do solo. No entanto seu valor também variou em decorrência de outras inter-relações existentes, as quais estão relacionadas aos teores de argila, silte e matéria orgânica. / The objective of this study is to measure the vertical and horizontal distribution of cone index (CI) values in no- till systems and the influence of soil water content. Data were interpolated allowing for cause and effect analysis. Other important factors as clay and silte content, bulk density, porous space and organic matter content had been monitored. A hydraulically penetrometer was used together with GPS receiver, soil auger and computer programs to collect and analize the data in tree different areas. Results allowed for the generation of maps of the attributes on different depts, and the regression among the interpolated data, choosing the models with the higher determination coefficient (R2). It was evidenced, in all areas, high CI values at depth betwen 0,1 to 0,2 m. Lower values of CI occurred, in one of the areas, in the same place of higher organic matter, in the same located of higher clay and silt content. The visualization of relationship between two factors in the maps and the regression among the interpolated values extracted from those maps was not always possible, but when that possibility took place, the relationship between the CI and water content, as the other spatial relations, was visible in the maps and achievable by the modeling of the data extracted from them. The CI was first influenced by the water content, bulk density and porous space. Nevertheless it also varied as function of clay, silte and organic matter content.

A resiliência física de solos é proveniente de processos regenerativos que incluem ciclos de umedecimento e secamento, congelamento e descongelamento assim como as atividades biológicas. Este estudo testou a hipótese de que as propriedades físicas do solo,tais como a permeabilidade do solo ao ar, densidade do solo, porosidade de aeração e porosidade total são indicadores físicos eficientes para quantificar a resiliência de solos de diferentes texturas submetidos ao estresse mecânico (compactação) e após subseqüentes ciclos de umedecimento e secamento. O objetivo foi avaliar o comportamento e a resiliência do solo por meio de propriedades físicas de um Latossolo Vermelho. Foram retiradas 25 amostras indeformadas (0-0,05m) de dois solos: solo I com textura argilosa e solo II com textura franco argilo arenosa, realizando as determinações das propriedades físicas nos tratamentos: antes da compactação(A), depois da compactação (C0) e após ciclos de umedecimento e secamento (C1,C2,C3,C4). As propriedades densidade do solo e porosidade total não apresentaram recuperação da condição inicial após a compactação nos solos I e II, as propriedades conteúdo volumétrico de água e porosidade de aeração apresentaram recuperação parcial apenas no solo I, para o solo II também não apresentaram recuperação, e a permeabilidade do solo ao ar foi a propriedade que apresentou a melhor recuperação assim como foi a que apresentou maior resiliência. Em relação ao distinto comportamento dos dois solos, observou-se que o solo I foi mais resiliente que o solo II nas propriedades que apresentaram recuperação. / The soil physical resilience comes from regenerative processes which include cycles of wetting and drying, freezing and thawing as well as biological activities. This study tested the hypothesis that the physical properties of soil such as soil permeability, bulk density, aeration porosity and total porosity are efficient physical indicators to quantify the resilience of soils of different textures subjected to mechanical stress (compression) and after subsequent cycles of wetting and drying. The objective was to evaluate the behavior and soil resilience by means of physical properties of an Oxisol. Undisturbed samples were taken 25 (0-0.05 m) of two soils: clayey soil and soil with sandy clay loam texture, making determinations of physical properties in the treatments before compression (A), after compaction (C0) and after wetting and drying cycles (C1, C2, C3, C4). The bulk density properties and porosity did not recover the initial condition after compression in the soil I and II, the properties volumetric content of water and air-filled porosity showed only partial recovery in the soil I, II to the soil also showed no recovery and soil permeability to air was the property that showed the best recovery as well as showed the greatest resilience. Regarding the different behavior of the two soil, it was observed that the soil I was more resilient soil II in which showed recovery properties

Os ecossistemas naturais e agropecuários dependem fundamentalmente do solo como recurso básico para sua funcionalidade. Neste contexto, a qualidade do solo tem tido uma crescente importância global. Os objetivos deste estudo consistiram em propor modificações metodológicas e/ou instrumentais visando determinações mais acuradas dos indicadores da qualidade física do solo mediante o desenvolvimento de (i) um sistema eletro-mecânico que permite a obtenção de amostras indeformadas de solos sem aplicação de golpes; (ii) um penetrômetro estático automatizado, de baixo custo e portátil, para medidas de resistência à penetração (RP) e resistência tênsil (RT) sob regime de velocidade constante de 1,55 mm s-1; (iii) um consolidômetro, de baixo custo e de maior portabilidade, para determinações da curva de compressão do solo, da RP e da RT utilizando propulsão pneumática e (iv) melhorias instrumentais em um permeâmetro de carga constante de ar pela redução de oscilações durante a medição do gradiente de pressão bem como a otimização da seleção de diferentes níveis de vazão mássica de ar. Os resultados obtidos mostraram que (i) o sistema eletromecânico garantiu a preservação da estrutura do solo em amostras coletadas comparado com a amostragem por golpes, principalmente no solo mais argiloso; (ii) a RP e a RT puderam ser determinadas com elevada acurácia à velocidade constante de 1,55 mm s-1; (iii) a curva de compressão do solo foi sensível às diferenças entre os tratamentos (linha e entrelinha da cultura) e a utilização de propulsão pneumática não influenciou os resultados da RP e da RT e (iv) a instrumentação utilizada no permeâmetro de carga constante de ar permitiu realizar determinações da permeabilidade do solo ao ar tanto em campo quanto em laboratório com rapidez e elevada acurácia. / Natural and agricultural ecosystems rely fundamentally on soil as a basic resource for their functionality. In this context, soil quality has had a growing global importance. The objectives of this study were based on proposing methodological and/or instrumental modifications aiming to obtain more accurate determinations of soil physical quality indicators by developing: (i) an electro-mechanical system that allows the extraction of undisturbed soil samples without mechanical impact (no-hammering); (ii) a low cost and portable static automatic penetrometer, for measuring soil penetration resistance (PR) and tensile strength (TS) at a constant speed of 1.55 mm s-1; (iii) a low cost and portable consolidometer, for determination of soil compression curve, PR and TS using pneumatic propulsion and (iv) instrumental improvements to a constant head air permeameter by reducing the oscillation during measuring the pressure head gradient and the optimization of the selection of different levels of air mass flow. The results showed that (i) the electro-mechanical system ensured the preservation of soil structure in undisturbed samples in comparison to samples extracted by hammering procedures, especially in clayey soil; (ii) PR and TS could be determined with high accuracy at the constant speed of 1.55 mm s-1; (iii) the soil compression curve was sensitive to differences between treatments (crop row and inter-row) and the use of pneumatic propulsion did not influence the results of PR and TS, and (iv) the instrumentation used in the constant head air permeameter allowed determination of soil air permeability either on the field or in the laboratory with high speed and accuracy.

O desenvolvimento econômico brasileiro depende da crescente produção agropecuária, aliada ao conservacionismo. O sistema de plantio direto é o manejo de solo que reúne o mais amplo conjunto de preceitos da agricultura conservacionista. As áreas agrícolas cultivadas sob plantio direto, entretanto, têm apresentado duas camadas de solo distintas: uma entre, aproximadamente, 0 e 7 cm de profundidade, com condições físicas e químicas favoráveis ao desenvolvimento radicular; e uma entre, aproximadamente, 7 e 20 cm de profundidade, com menor permeabilidade do solo ao ar e a água, elevada resistência à penetração e baixa fertilidade química do solo. Estas condições promovem a concentração do sistema radicular das plantas agrícolas cultivadas na camada mais superficial do solo (0 a 7 cm), motivando perdas de produtividade por estresse hídrico. A magnitude desse problema se estende a mais de 30 milhões de hectares de lavoura cultivada sob plantio direto no Brasil, colocando em risco as projeções de exuberância da agricultura no país. Assim, o desenvolvimento desta tese teve o objetivo de estudar fatores que, além do processo de compactação mecânica do solo, possam estar promovendo a estratificação física e química de solos altamente intemperizados cultivados sob sistema de plantio direto. Dentre os possíveis fatores causadores deste tipo de degradação, foram avaliados: i) a aplicação excessiva de calcário, exclusivamente em superfície, ocasionando, na camada de 0 a 7 cm, a elevação do pH do solo para além do ponto de carga zero do solo, elevando o potencial eletronegativo do solo e por consequência, promovendo a dispersão de argila; ii) a migração da argila dispersa no perfil do solo, pela água de percolação, como um fator promotor de degradação física em subsuperfície; iii) o aporte de fitomassa ao solo em quantidade e qualidade para manter a estabilidade estrutural dos solos cultivados. Os resultados obtidos mostraram que o movimento de calcário no perfil dos solos estudados é muito lento, limitando o efeito deste produto a poucos centímetros abaixo do local onde ele é depositado ou incorporado (2,5 cm em 130 semanas), independentemente da dose aplicada (até 33,2 Mg ha-1). Assim, a calagem superficial promove e intensifica a estratificação dos atributos químicos no perfil do solo, aumentando, demasiadamente, o pH próximo à superfície e sendo ineficiente em mitigar a acidez na subsuperficie destes solos. A concentração de calcário na camada mais superficial dos solos altamente intemperizados aumenta a eletronegatividade do solo, resultando na dispersão de argila. A migração dos argilominerais dispersos no perfil do solo, pela água de percolação, promove uma série de alterações estruturais, incluindo a diminuição da porosidade total e da continuidade dos poros e o aumento da densidade e da resistência do solo à penetração na camada subsuperficial. A diminuição da estabilidade estrutural dos Latossolos sob cultivo também está ligada ao aporte de material orgânico ao solo em quantidade e qualidade inferiores à que ocorre no solo sob sistema nativo. Os Latossolos cauliníticos são mais propensos a diminuição da estabilidade estrutural quando submetidos ao cultivo. Portanto, a recomendação de calagem em solos altamente intemperizados cultivados sob plantio direto, precisa considerar a mineralogia do solo e a possível degradação estrutural promovida pela calagem em excesso. / The economic development of Brazil depends upon the increasing agricultural production associated with conservation practices. The no-tillage system is the soil management practice that brings together the broadest set of principles for conservation agriculture. Areas under no-till system, however, generally have two completely different soils layers: a surface layer, around 0 to 7 cm, with physical and chemical conditions favorable for root development; and a sub-surface layer, around 7 to 20 cm, with lower permeability to air and water, high soil penetration resistance, and low soil fertility. The existence of these stratified layers dramatically restricts the development of the root system into the sub-surface soil layer, which may result in reducing plant productivity by water deficit. This problem exists on more than 30 million hectares cultivated under no-tillage system in Brazil, and can compromise the optimistic projections of agricultural growth in the country. Therefore, more research is necessary to explore challenges that come with no-tillage. The aim of this thesis was to study the factors that can promote the physical and chemical stratification of highly weathered soils cultivated under no-till system. Among the factors that could cause this degradation, the following were studied: i) the application of excessive lime only on surface soil, or into the uppermost soil layer, which can increase its pH to levels beyond of the zero point of charge of soil, raising its electronegative potential and promoting, as a consequence, the clay dispersion; ii) the dispersed clay migration thtough the soil profile, by the percolation water, as a factor of physical degradation of sub-surface of soil cultiveted under no-tillage; and iii) the aplication of phytomass to the soil in insufficient amount and quality to maintain the soil structural stability of the soil. The results of this study showed that lime movement into the deeper soil profile, is very slow, as its impacts are limited to just a few centimeters below of where it is applied or incorporated (2.5 cm after 130 weeks), independent of the applied amount of lime. Thus, the surface lime application intensifies the chemical stratification of the clayey soils under no-tillage, increasing to much the soil pH of the uppermost soil layer, and being inefficient to decrease the soil acidity in the subsurface soil layer. The concentration of lime into the uppermost soil layer can significantly increase the electronegativity of the soil system and result in clay dispersion in the topsoil layer (0 to 5 cm). The resulting clay migration into the soil profile led to a series of structural alterations in subsurface layers, including: decrease of both soil porosity and pore continuity; and increase of both soil bulk density and soil penetration resistance in the sub-superficial layer. The structural stability decreasing of Oxisols under no-till system also is linked with the low addition of organic matter to the cultivated soil, in relation to the non-cultivated soils. The kaolinitic Oxisols are more susceptible to degradation than the gibbsitic Oxisols. Thus, it could be conclude that liming practices (rate and application methods of lime), mainly under no-till systems, need to consider both type and mineralogy of soil, as well as considering soil structure degradation promoted by over-liming in the uppermost soil layer.

Made available in DSpace on 2017-07-10T19:24:51Z (GMT). No. of bitstreams: 1 Almiro Weiss.pdf: 7452787 bytes, checksum: 197399ca28d2e0c6c30badfe29ff070b (MD5) Previous issue date: 2005-07-01 / The compaction of the agricultural soils has worldwide importance because of the increasing of the farm with machinery resulting in the increasing of heavy machines for cultivation system, mainly, in the developed countries. The term, soils compaction refers to the compression carried out on the non-saturated soil, during which an increase of bulk density exists, producing the reduction of its volume of pores like a consequence. The excessive compaction has damaging consequences for the agriculture and environmental. For this reason, the state of soils compacting has received enough attention from researchers and agricultural farmers. The uniaxial compression has been used for predicting the agricultural soils compaction with so much efficiency. In accordance to the previous exposure, in this paper aimed the to develop an apparatus of uniaxial compression of the soil for testing in laboratory and evaluating its performance. The apparatus is composed by a pneumatic press, where the sample of soil is packaged in a metallic volumetric ring (made in steel carbon - ABNT 1020), with thickness of wall of 0,2 cm, internal diameter of 7,0 cm and two options of height of 2,4 cm and 4,8 cm. Cyclical loads of compression were applied to the sample in order to verify the variation of the soil deformation. A lineal transducer detects the samples behavior during the compression and uncompression (relaxation) uniaxial indicating in the digital counter s display the variations of measure of the sample deformation. Successive loads of 150, 200, 300, 400, 500, 600, 700 and 800 kPa were applied in periods of 60 s for compression and 120 s for uncompression of the sample. The results allowed conclude that the system presents answers with good precision and greater versatility with the variation of de samples size for compression. / A compactação dos solos agrícolas tem importância mundial em função do crescimento das áreas mecanizadas, acarretando o aumento de máquinas pesadas nos sistemas de cultivo, principalmente, nos países desenvolvidos. O termo compactação do solo refere-se a sua compressão realizada no solo não saturado, durante a qual existe um aumento de densidade produzindo como conseqüência redução de seu volume de poros. A excessiva compactação tem conseqüências danosas para a agricultura e para o meio ambiente. Por essas razões, o estado de compactação do solo tem recebido bastante atenção de pesquisadores e produtores agrícolas. O ensaio de compressão uniaxial tem sido utilizado para determinar a compactação dos solos agrícolas com muita eficiência. Face ao exposto, este trabalho estabeleceu como objetivo desenvolver um aparelho de compressão uniaxial do solo para ensaio em laboratório e avaliar o seu desempenho. O aparelho é composto por uma prensa pneumática, em que a amostra de solo fica acondicionada em um anel volumétrico metálico (feito em aço carbono - ABNT 1020, cromado), com espessura de parede de 0,2 cm, com diâmetro interno de 7,0 cm e com duas opções de altura de 2,4 cm e 4,8 cm. Cargas cíclicas de compressão foram aplicadas na amostra para verificar a variação da deformação do solo. Um transdutor linear detecta o comportamento da amostra durante a compressão e descompressão (relaxamento) uniaxial indicando no display do contador digital as variações de medida da deformação da amostra. Cargas seqüenciais de 150, 200, 300, 400, 500, 600, 700 e 800 kPa foram aplicadas em intervalos de tempo de: 60 s para compressão e 120 s para descompressão da amostra. Os resultados permitiram concluir que o sistema apresenta respostas com boa precisão e maior versatilidade, com variação do tamanho das amostras para compressão.

Made available in DSpace on 2017-07-10T19:25:02Z (GMT). No. of bitstreams: 1 Veruschka Rocha Medeiros Andreolla.pdf: 1722558 bytes, checksum: bb4f5cea73e94834a80a8b228456a12b (MD5) Previous issue date: 2005-08-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to verify the influence of pasture in side of agriculture-cattle integration on the physical characteristics of the ground, to evaluate the influence of these parameters and the staggered of a planter (connecting rod and record of cut) on the grain yield of the soy and to quantify the energy performance of the planter in ground submitted to the trampling of animals. An experiment in Oxissol, situated was become fulfilled in the Santa Maria Farm, Santa Tereza do Oeste - PR, in the period of April of 2003 the April of 2004. The delineation in subdivided parcels "Split Plot" entirely randomized was used. The main treatments had been composed by pasture with the ground humid or wet, pasture with alone dry and without pasture, with a capacity of 26 U.A. ha 1. The secondary treatments had been composites for the mechanisms staggered of the planter (double connecting rod or records for deposition of the seasoning). Each plot with a area 1600 m2 (50 x 32 m) and the subparcels had dimensions of 20 x 8 m, with area of 160 m2. Physical properties of the ground, parameters of performance of the tractor-planter set and grain yield of the soy had been evaluated. The values gotten in the experiments had shown the effect of the cattle trampling in compacting the ground in the layer until the 10 cm initial. The sharp peak in the resistance to the penetration the 5 cm can be indicating that the maximum mobilization of the resistance of the ground occurred at the depth 5 cm. The root of the soy had promoted the decompaction of the ground, showing a trend of return to the initial structural condition of it. The tension-deformation analysis corroborated the results of the assays of compacting in laboratory, as well as the deformation curve revealed consistent with the profiles of resistance to the penetration in the field. The action of the cattle trampling on the ground modified the density conditions and cone index, however was not enough to intervene with the demand of power in the three studied conditions. The planter with staggered of records had exerted minor power and snatch force and the speed of displacement of the set was about 6,4 % greater in relation to the staggered connecting rod. The grain yield of the soy was not modified significantly by the handling systems, but when the mechanism was used connecting rod in the planter, the production of grains bigger when was compared with the planter equipped with staggered of records. / O objetivo deste trabalho foi verificar a influência do pastejo em área de integração lavoura-pecuária sobre as características físicas do solo, avaliar a influência desses parâmetros e dos elementos sulcadores de uma semeadora (haste e disco de corte) sobre a produtividade da soja e quantificar o desempenho energético da semeadora em solo submetido ao pisoteio do gado. Realizou-se um experimento em LATOSSOLO VERMELHO Eutroférrico, situado na Fazenda Santa Maria, em Santa Tereza do Oeste PR, no período de abril de 2003 a abril de 2004. Foi utilizado o delineamento em parcelas subdivididas Split Plot inteiramente casualizado. Os tratamentos principais foram compostos pelo pastejo com o solo úmido ou molhado, pastejo com solo seco e sem pastejo, com uma lotação de 26 U.A. ha 1 (unidade animal por hectare). Os tratamentos secundários foram compostos pelos elementos sulcadores da semeadora (haste ou discos duplo para deposição do adubo). Cada parcela com um total de 1600 m2 (50 x 32 m) e as subparcelas tinham dimensões de 20 x 8 m, com total de 160 m2. Foram avaliadas propriedades físicas do solo, variáveis de desempenho do conjunto trator-semeadora e rendimentos de grãos da soja. Os valores obtidos nos experimentos mostraram o efeito do pisoteio do gado em compactar o solo na camada até os 10 cm iniciais. O pico pronunciado na resistência à penetração a 5 cm pode ser indicador de que a máxima mobilização da resistência do solo ocorreu à profundidade 5 cm. Os sulcadores de haste promoveram a descompactação do solo conciliando assim com o efeito descompactador das raízes da aveia e da soja, mostrando uma tendência de retorno à condição estrutural inicial do mesmo. A análise tensão-deformação corroborou os resultados dos ensaios de compactação em laboratório, assim como a curva de deformação mostrou-se consistente com os perfis de resistência à penetração no campo. A ação do pisoteio do gado sobre o solo alterou as condições de densidade e resistência à penetração, entretanto não foi suficiente para interferir na demanda de potência nas três condições estudadas. A semeadora com sulcadores de discos exigiu menor força de tração e potência e a velocidade de deslocamento do conjunto foi cerca de 6,4 % maior em relação ao sulcador haste. O rendimentos de grãos da soja não foi alterado significativamente pelos sistemas de manejo, mas quando foi utilizado o elemento haste na semeadora, a produção de grãos foi maior quando comparada com a semeadora equipada com sulcadores de discos.

Made available in DSpace on 2017-05-12T14:48:14Z (GMT). No. of bitstreams: 1 Almiro Weiss.pdf: 7452787 bytes, checksum: 197399ca28d2e0c6c30badfe29ff070b (MD5) Previous issue date: 2005-07-01 / The compaction of the agricultural soils has worldwide importance because of the increasing of the farm with machinery resulting in the increasing of heavy machines for cultivation system, mainly, in the developed countries. The term, soils compaction refers to the compression carried out on the non-saturated soil, during which an increase of bulk density exists, producing the reduction of its volume of pores like a consequence. The excessive compaction has damaging consequences for the agriculture and environmental. For this reason, the state of soils compacting has received enough attention from researchers and agricultural farmers. The uniaxial compression has been used for predicting the agricultural soils compaction with so much efficiency. In accordance to the previous exposure, in this paper aimed the to develop an apparatus of uniaxial compression of the soil for testing in laboratory and evaluating its performance. The apparatus is composed by a pneumatic press, where the sample of soil is packaged in a metallic volumetric ring (made in steel carbon - ABNT 1020), with thickness of wall of 0,2 cm, internal diameter of 7,0 cm and two options of height of 2,4 cm and 4,8 cm. Cyclical loads of compression were applied to the sample in order to verify the variation of the soil deformation. A lineal transducer detects the samples behavior during the compression and uncompression (relaxation) uniaxial indicating in the digital counter s display the variations of measure of the sample deformation. Successive loads of 150, 200, 300, 400, 500, 600, 700 and 800 kPa were applied in periods of 60 s for compression and 120 s for uncompression of the sample. The results allowed conclude that the system presents answers with good precision and greater versatility with the variation of de samples size for compression. / A compactação dos solos agrícolas tem importância mundial em função do crescimento das áreas mecanizadas, acarretando o aumento de máquinas pesadas nos sistemas de cultivo, principalmente, nos países desenvolvidos. O termo compactação do solo refere-se a sua compressão realizada no solo não saturado, durante a qual existe um aumento de densidade produzindo como conseqüência redução de seu volume de poros. A excessiva compactação tem conseqüências danosas para a agricultura e para o meio ambiente. Por essas razões, o estado de compactação do solo tem recebido bastante atenção de pesquisadores e produtores agrícolas. O ensaio de compressão uniaxial tem sido utilizado para determinar a compactação dos solos agrícolas com muita eficiência. Face ao exposto, este trabalho estabeleceu como objetivo desenvolver um aparelho de compressão uniaxial do solo para ensaio em laboratório e avaliar o seu desempenho. O aparelho é composto por uma prensa pneumática, em que a amostra de solo fica acondicionada em um anel volumétrico metálico (feito em aço carbono - ABNT 1020, cromado), com espessura de parede de 0,2 cm, com diâmetro interno de 7,0 cm e com duas opções de altura de 2,4 cm e 4,8 cm. Cargas cíclicas de compressão foram aplicadas na amostra para verificar a variação da deformação do solo. Um transdutor linear detecta o comportamento da amostra durante a compressão e descompressão (relaxamento) uniaxial indicando no display do contador digital as variações de medida da deformação da amostra. Cargas seqüenciais de 150, 200, 300, 400, 500, 600, 700 e 800 kPa foram aplicadas em intervalos de tempo de: 60 s para compressão e 120 s para descompressão da amostra. Os resultados permitiram concluir que o sistema apresenta respostas com boa precisão e maior versatilidade, com variação do tamanho das amostras para compressão.

Made available in DSpace on 2017-05-12T14:48:24Z (GMT). No. of bitstreams: 1 Veruschka Rocha Medeiros Andreolla.pdf: 1722558 bytes, checksum: bb4f5cea73e94834a80a8b228456a12b (MD5) Previous issue date: 2005-08-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to verify the influence of pasture in side of agriculture-cattle integration on the physical characteristics of the ground, to evaluate the influence of these parameters and the staggered of a planter (connecting rod and record of cut) on the grain yield of the soy and to quantify the energy performance of the planter in ground submitted to the trampling of animals. An experiment in Oxissol, situated was become fulfilled in the Santa Maria Farm, Santa Tereza do Oeste - PR, in the period of April of 2003 the April of 2004. The delineation in subdivided parcels "Split Plot" entirely randomized was used. The main treatments had been composed by pasture with the ground humid or wet, pasture with alone dry and without pasture, with a capacity of 26 U.A. ha 1. The secondary treatments had been composites for the mechanisms staggered of the planter (double connecting rod or records for deposition of the seasoning). Each plot with a area 1600 m2 (50 x 32 m) and the subparcels had dimensions of 20 x 8 m, with area of 160 m2. Physical properties of the ground, parameters of performance of the tractor-planter set and grain yield of the soy had been evaluated. The values gotten in the experiments had shown the effect of the cattle trampling in compacting the ground in the layer until the 10 cm initial. The sharp peak in the resistance to the penetration the 5 cm can be indicating that the maximum mobilization of the resistance of the ground occurred at the depth 5 cm. The root of the soy had promoted the decompaction of the ground, showing a trend of return to the initial structural condition of it. The tension-deformation analysis corroborated the results of the assays of compacting in laboratory, as well as the deformation curve revealed consistent with the profiles of resistance to the penetration in the field. The action of the cattle trampling on the ground modified the density conditions and cone index, however was not enough to intervene with the demand of power in the three studied conditions. The planter with staggered of records had exerted minor power and snatch force and the speed of displacement of the set was about 6,4 % greater in relation to the staggered connecting rod. The grain yield of the soy was not modified significantly by the handling systems, but when the mechanism was used connecting rod in the planter, the production of grains bigger when was compared with the planter equipped with staggered of records. / O objetivo deste trabalho foi verificar a influência do pastejo em área de integração lavoura-pecuária sobre as características físicas do solo, avaliar a influência desses parâmetros e dos elementos sulcadores de uma semeadora (haste e disco de corte) sobre a produtividade da soja e quantificar o desempenho energético da semeadora em solo submetido ao pisoteio do gado. Realizou-se um experimento em LATOSSOLO VERMELHO Eutroférrico, situado na Fazenda Santa Maria, em Santa Tereza do Oeste PR, no período de abril de 2003 a abril de 2004. Foi utilizado o delineamento em parcelas subdivididas Split Plot inteiramente casualizado. Os tratamentos principais foram compostos pelo pastejo com o solo úmido ou molhado, pastejo com solo seco e sem pastejo, com uma lotação de 26 U.A. ha 1 (unidade animal por hectare). Os tratamentos secundários foram compostos pelos elementos sulcadores da semeadora (haste ou discos duplo para deposição do adubo). Cada parcela com um total de 1600 m2 (50 x 32 m) e as subparcelas tinham dimensões de 20 x 8 m, com total de 160 m2. Foram avaliadas propriedades físicas do solo, variáveis de desempenho do conjunto trator-semeadora e rendimentos de grãos da soja. Os valores obtidos nos experimentos mostraram o efeito do pisoteio do gado em compactar o solo na camada até os 10 cm iniciais. O pico pronunciado na resistência à penetração a 5 cm pode ser indicador de que a máxima mobilização da resistência do solo ocorreu à profundidade 5 cm. Os sulcadores de haste promoveram a descompactação do solo conciliando assim com o efeito descompactador das raízes da aveia e da soja, mostrando uma tendência de retorno à condição estrutural inicial do mesmo. A análise tensão-deformação corroborou os resultados dos ensaios de compactação em laboratório, assim como a curva de deformação mostrou-se consistente com os perfis de resistência à penetração no campo. A ação do pisoteio do gado sobre o solo alterou as condições de densidade e resistência à penetração, entretanto não foi suficiente para interferir na demanda de potência nas três condições estudadas. A semeadora com sulcadores de discos exigiu menor força de tração e potência e a velocidade de deslocamento do conjunto foi cerca de 6,4 % maior em relação ao sulcador haste. O rendimentos de grãos da soja não foi alterado significativamente pelos sistemas de manejo, mas quando foi utilizado o elemento haste na semeadora, a produção de grãos foi maior quando comparada com a semeadora equipada com sulcadores de discos.

Prediction as a tool in engineering has been used in taking right judgement in many of the professional activities. This being the fact, the role and significance of prediction in geotechnical practice needs no emphasis. Bulk of all man made structures are either made of soil or are resting on natural soil, involving large quantities of soil. Thus, it is often necessary for the geotechnical engineer to quickly characterize the soil and determine their engineering properties, so as to assess the suitability of the soil for any specific purpose. Obtaining these properties requires undisturbed samples, which involves time and money, and also elaborate laboratory procedures. Thus, it is desirable to find simpler and quicker methods of testing, using the data of which the engineering properties can be predicted satisfactorily especially so, for preliminary design purposes. Most often this can be achieved from simple tests known as inferential tests, and the engineering properties namely, compressibility, swell/collapse, hydraulic conductivity, strength and compaction characteristics can be obtained from empirical/semi-empirical correlations. The index tests namely the Atterberg limits form the most important inferential soil tests with very wide universal acceptance. These tests are relatively simple to perform and have provided a basis for explaining most engineering properties of soils in geotechnical practice. In this direction, this investigation has been carried out to correlate the engineering properties with the simple index properties and their indices, namely, the liquid limit, plastic limit, shrinkage limit, plasticity index and shrinkage index (liquid limit - shrinkage limit). Any good correlation in the prediction of engineering properties with the index properties will enhance the use of simple test for prediction purposes. This thesis is an attempt towards this direction. It is often necessary to identify the basic mechanisms controlling the engineering properties from a micro-mechanistic point of view and correlate with the index properties, thereby facilitating prediction of engineering properties better. Though attempts have been made in the past to predict the engineering properties of soils from the index properties/indic­es, they are not quite satisfactory. This thesis is an attempt to predict the engineering properties of fine-grained soils from the index properties taking into consideration the mechanisms controlling them. Since, the index properties are used for prediction of engineering properties, the existing methods of determining the same have been examined carefully and critically. It's satisfactory determination is found important because other indices namely plasticity index, Ip and shrinkage index, Is = (wL - ws), are determined based on it. Also the liquid limit is one of the important and widely used parameter in various existing correlations. In this direction, two new methods of determining the liquid limit have been developed, namely (i) absorption water content and liquid limit of soils and (ii) liquid limit from equilibrium water content under Ko-stress. In the absorption water content method, the water absorbed by an oven dried soil pat at equilibrium gives a good correlation with the liquid limit of soils. Here, the water holding capacity at equilibrium goes well with the mechanism of liquid limit, which is also the water holding capacity of a soil at a particular small but measurable shear strength. A good relationship is found to exit between the absorption water content, wA and the liquid limit, wL, and it is given as : WA = 0.92 wL (i) In the second method, namely, the liquid limit from equilibrium water content under K0-stress, which is the equilibrium water content under a Ko stress of 0.9 kPa is found to be equal to the liquid limit obtained from the cone penetration method of determining the liquid limit It is found that this method of determining the liquid limit overcomes the limitations of the conventional methods of determining the liquid limit, also easy to determine with a simple apparatus and has good repeatability. Determination of plastic limit of the soils by the rolling thread method often poses a problem especially when the soil is less plastic. Hence, to overcome this problem, a new method has been proposed to predict the plasticity index in terms of the flow index. The relationship between the plasticity index and the flow index by the cone penetration cup method is found to be better than by the percussion cup method. Since, the cone penetration method of the liquid limit determination is more popular than the percussion cup method, the flow index from the cone method is recommended to determine the plasticity index from the correlation as given below: (/p)c = 0.74 Ifc (ii) Thus, the plastic limit can be determined with the plasticity index, thereby dispensing with the determination of plastic limit by the thread method. The determination of consolidation characteristics form an important aspect in the design of foundations and other earth retaining structures. The determination of consolidation characteristics namely the compression index, the coefficient of consolidation and the coefficient of secondary compression is time consuming. So, researchers have resorted to correlating the compressibility behaviour with simple index properties. While attempts have been made in the past to correlate the compressibility behaviour with various index properties individually, all the important properties affecting the compressibility behaviour has not been considered together in any single study to examine which of the index property/properties of the soils correlates better with the compressibility behaviour, especially with the same set of test results. Number of existing correlations with the liquid limit alone as a primary index property correlating with the compression index have limitations in that they do not consider the plasticity characteristics of the soils fully. The index parameter, shrinkage index, Is has a better correlation with the compression index, Cc and also the coefficient of volume change, mv than plasticity index. Coefficient of consolidation, Cv has also shown to correlate well with shrinkage index than the plasticity index. Even the coefficient of secondary compression, Cαε has shown to have a better correlation with shrinkage index than the plasticity index. However, liquid limit has a poor correlation with all the compressibility characteristics. The correlation of Cc and Cv with shrinkage index, Is is as given below: Cc = 0.007 (Is + 18) (iii) Cv = 3x10-2 (Is)-3.54 (in m2/sec) Further, to reduce the testing time of conventional consolidation test in order to obtain the compressibility characteristics, a new method known as rapid method of consolidation has been proposed, which is very effective in enormously reducing the time of consolidation without sacrificing the accuracy of the end results. The time required in the rapid method of consolidation testing could be as low as 4 to 5 hours to complete the whole test as compared to 1 to 2 weeks as the case may be by the conventional consolidation test. Using any curve fitting procedure the degree of consolidation, U for any pressure increment can be found out. Thus, the effective pressure at that stage can be calculated and further the pressure incremented without further delay. This procedure is repeated for every pressure increment with a load increment ratio of unity till the desired pressure level is reached. Even for a highly compressible soil like BC soil with a liquid limit of 73.5 %, the consolidation test could be completed within 5 hours by the rapid method, without any sacrifice of the accuracy of the results as compared to 7 days by the conventional method to reach a pressure of 800 kPa. Hydraulic conductivity is one of the basic engineering properties of soils. Of late hydraulic conductivity of fine-grained soils has assumed greater importance in waste disposal facilities. From the present investigation it is found that hydraulic conductivity with water for each pair of soils having nearly the same liquid limit but different plasticity properties is found to be vastly different, but found to correlate well with shrinkage index. A method to predict the hydraulic conductivity of fine -grained soils as a function of void ratio is proposed with the use of shrinkage index as given below: k = C [ ] (in m/sec) (v) 1 + e C = 2.5 x 10-4 (/s)-5.89 and n = 4 (vi) It has also been brought out that as the dielectric constant of the pore fluid decreases; there is a drastic increase in the intrinsic permeability of soil. These changes are attributed to the significant reduction in the thickness of diffuse double layer, which in turn is mainly dependent on the dielectric constant of the pore fluid. The quantification of the change in the hydraulic conductivity with the change in the pore fluids of extreme dielectric constant, i.e., from water to carbon tetrachloride could be expressed in terms of the volume of water held in the diffuse double layer and the same has a good correlation with shrinkage index. With the advancement in the knowledge of the engineering behaviour of fine-grained soils, there is an increasing trend toward larger involvement of fine-grained soils in earth structures and foundations. Though extensive work has been done in the past to understand the swelling behaviour of expansive soils and the mechanisms involved therein, it is yet not satisfactory. From the literature it can be seen that lot of work has been done to correlate the swell potential with various physical properties. The simple means of identifying the swelling type of soils is by means of free swell tests with the ratio of free swell with carbon tetrachloride to the free swell of water. The same has found to correlate well with the percent swell/collapse of the ten soils used in the present investigation. However, it was found that shrinkage index has a better correlation with the swell/collapse behaviour of fine-grained soils, compared to the liquid limit or the plasticity index. In this study, it is also shown that neither the liquid limit nor the plasticity index can qualitatively describe the swell/collapse behaviour of fine-grained soils. This has been attributed primarily to two different mechanisms governing montmorillonitic and kaolinitic soils separately. Even swelling pressure has shown to have a good correlation with shrinkage index. It is found that the compression index of the samples consolidated from the swollen condition correlates well with the shrinkage index. Laboratory determination of the compaction characteristics are very much important for use in earth work constructions. It is found that only the plastic limit bears a good correlation with the compaction characteristics namely optimum moisture content and maximum dry unit weight. This conclusion is also supported by the data from the literature. The correlations are given as: OMC = 0.92 wp (in percent) (viii) and ydmax = 0.23 (93.3 - wp) (inkN/m3) (ix) Liquid limit, plasticity index and shrinkage index do not bear any correlation with the compaction characteristics. It is quite possible that, the plastic limit, which is the optimum water content of a saturated soil at which it behaves as a plastic material, and thus can be moulded to any shape, thereby the soil can be compacted or moulded to the densest possible state at that water content. Hence, possibly the good correlation. A simple method to predict the compaction curve is proposed based on the plastic limit of the soils. Of all the important engineering properties, both volume change (compressibility and swelling) and hydraulic conductivity have good correlation with the shrinkage index. However, the compaction characteristics correlate well with the plastic limit. Herein, an hypothesis is proposed to possibly explain why shrinkage index has shown to be a better parameter to correlate with most of the engineering properties with the exception of the compaction characteristics. The liquid limit is a parameter which takes part of the plasticity characteristics of a soil. Recently it has been well brought out that shrinkage limit is primarily a function of how the varying grain sizes are distributed in a soil. Thus, shrinkage limit takes care of the gradation of the soil fractions in it. Thus, by considering the shrinkage index, which is the difference of the liquid limit water content on one end and shrinkage limit water content on the other end, the primary physical properties of the soils namely the plasticity and the grain size distribution are considered. This possibly explains the good correlation of shrinkage index with the engineering properties of fine-grained soils. However, compaction being a moulding of the soils into a compact state, it has a good correlation with the plastic limit, which is the optimum water content of a saturated soil at which it behaves as a plastic material, and thus can be moulded to any shape, thereby the soil can be compacted or moulded to the densest possible state at that water content. Hence, the good correlation. As the present investigation gives the correlative equations to predict the engineering properties of fine-grained soils from the appropriate index properties, which are obtained from simple and quick laboratory tests, it is hoped that this will go a long way in being a handy tool for a practicing geotechnical engineer in the preliminary assessment of fine-grained soils and thereby take appropriate judgement in various aspects of geotechnical constructions with it.