Winter cropping often does not realise its full potential in south-western Victoria, where waterlogging is a major problem on the poorly drained soils of conventional cultivation (CC) systems. Consequently, cropping has been undertaken on raised beds (RB) to reduce the risk of waterlogging. Initial reports on the yields of RB were encouraging. It was hypothesized that an improvement in soil properties of RB may account for their better performance compared to CC systems. / The aim of the thesis was to evaluate selected soil physical properties of RB and to make comparisons with other treatments (CC and pasture). The specific objectives were to: 1) evaluate plant growth and crop yield; 2) quantify soil water dynamics; 3) assess changes in the soil water retention characteristic (SWRC), soil strength and soil hydraulic properties; 4) describe pore pathways from solute transport; and 5) quantify soil macropore structure. / Measurements of volumetric water content (θv) were taken at 20, 40, 60 and 80 cm and at the soil surface. These data allowed the determination of the profile soil water deficit (SWD), which was found to be greater under the RB than the CC, although at times the pasture had the largest SWD. The RB mostly remained drier than the CC, but the response to rainfall in the surface θv was similar between treatments. Below average rainfall was received during the whole study period which resulted in drier than normal conditions. / There was no consistent difference in plant growth between crops on the RB and CC; e.g. in 2004 periods of waterlogging resulted in greater dry matter production on the RB; while drier conditions in 2003 saw better crop growth on the CC. Grain yield varied annually according to rainfall, and overall the treatment yields were similar. Analysis of regional yield data showed that there was no yield difference in years with average or below average rainfall, but years with higher rainfall favoured RB. / Little difference was found in the laboratory-derived SWRC, but in the field the RB were consistently drier at all depths and at 60 cm depth the CC had a saturated zone. The RB were found to have a lower soil strength characteristic within the surface 24 cm compared to the CC. The air-filled porosity (AFP) was higher in the RB while for long periods the CC were <10 per cent AFP. There was no significant difference between the treatments in unsaturated hydraulic conductivity (Kus) in the soil surface. Saturated hydraulic conductivity (Ks) in the subsoil was very small, although the RB had significantly greater Ks than the CC. / A solute transport experiment investigated the movement of a solute in large soil cores of the RB and CC treatments. Derived parameters from a transfer function model were used to assess the solute transport characteristics. This showed that under nearly saturated conditions the CC had significantly greater solute spreading than the RB. Furthermore, the transport volume (θst) to θv ratio was smaller in the RB which indicated a greater proportion of preferential flow. These and other data suggested that the RB had a better connected and more stable pore network. / Soil macropore structure was quantified using image analysis of resin-impregnated soil. Samples were taken twice; the first samples showed that the RB had improved pore connectivity, slightly greater porosity and a pore network with smaller sized pore components than the CC. In comparison, at the second sampling time the structural parameters of the two treatments were similar. / Uncertainty exists in the scenario of higher rainfall or of the longer-term changes of soil properties under RB cropping. Nevertheless after three years of measurements, this thesis concludes that most soil physical properties of RB are distinctly better for cropping than under CC systems.

Made available in DSpace on 2014-06-11T19:23:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-27Bitstream added on 2014-06-13T20:30:04Z : No. of bitstreams: 1 silvajunior_jf_me_jabo.pdf: 787738 bytes, checksum: 7b3e41cb53972e8468ad03ecb64cfbe1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os óxidos de ferro são importantes indicadores ambientais e possuem grande influência nos atributos físicos e químicos do solo. Entretanto, para o melhor entendimento de sua formação e ocorrência são necessários estudos de variabilidade espacial. A geoestatística é a melhor ferramenta para este estudo, sendo que a Krigagem ordinária (KO) é um interpolador de mínimos quadrados, mais utilizado em ciência do solo. Porém, ela suaviza os detalhes locais da variação espacial, superestimando pequenos valores e subestimando altos valores. Por isso, ela revela-se inadequada na avaliação da verdadeira variabilidade espacial dos óxidos de ferro. Embora a krigagem mostre a melhor estimativa de um atributo Z, ele não representa bem a variação. Deste modo, a alternativa é simulação geoestatística que avalia e quantifica a incerteza de um atributo, de maneira mais realista. A técnica de simulação estocástica mais utilizada é a simulação sequencial gaussiana (SSG), por ser, rápida e direta na construção da função de densidade de probabilidade acumulada condicional (f.d.p.a.c), sendo, portanto preferível à estimação pela KO. Desta forma, é importante testar outros métodos para caracterizar espacial dos óxidos de ferro. Objetivando avaliar o desempenho da (KO), krigagem ordinária dos dados padronizados (KOP) e da simulação seqüencial gaussiana (SSG) da variabilidade espacial dos óxidos de ferro em uma área com pedoformas: côncava e convexa foram coletados 121 amostras de duas malhas nos dois relevos classificados como: côncavo e convexo com espaçamento de 10 metros. O erro médio, o erro quadrático médio e o erro quadrático médio padronizado foram os critérios de avaliação da acurácia da predição. Os valores altos dos coeficientes de variação dos óxidos de ferro afetaram o desempenho dos métodos... / Iron oxides are important environmental indicators and have great influence on the physical and chemical properties of soil. However, for a better understanding of their formation and occurrence studies are necessary spatial variability. Geostatistics is a tool for this study, ordinary kriging (OK) is a least squares interpolator, is the most widely used in soil science. However smooths out local details of spatial, small values overestimating and underestimating high values. Therefore, is inadequate in the evaluation of iron oxides. Although the kriging show the best estimate of an attribute Z, it does not represent well the variation. Thus, the alternative is geroestatisctical simulation that evaluates and quantify the uncertainty of an attribute, more realistically. Since the most widely used is the sequential Gaussian simulation (SGS), to be quickly and directly in the construction of the density function of cumulative probability (fdpac), and are preferred to the estimation. Thus, is important to test other methods to characterize spatially of iron oxides. In order to evaluate the performance of (OK), ordinary kriging of standardized data (OKS) and sequential Gaussian simulation (SGS) of the spatial variability of iron oxides in an area with landform: concave and convex 121 samples were collected data in two loops with two reliefs classified as concave and convex with spacing of 10 meters. The average error, the mean square error and root mean square error were standardized criteria for evaluating the accuracy of prediction. High values of coefficient of variation of iron oxides harmed the performance of the methods. The landforms showed variable differentiated by SGS. The maps of OKS and E-type had higher accuracy and greater detail in relation to landforms in the OK. It is recommended that E-type maps instead of maps OK... (Complete abstract click electronic access below)

Orientador: Gener Tadeu Pereira / Coorientador: José Marques Júnior / Banca: Ednaldo Carvalho Guimarães / Banca: Marcílio Vieira Martins Filho / Resumo: Os óxidos de ferro são importantes indicadores ambientais e possuem grande influência nos atributos físicos e químicos do solo. Entretanto, para o melhor entendimento de sua formação e ocorrência são necessários estudos de variabilidade espacial. A geoestatística é a melhor ferramenta para este estudo, sendo que a Krigagem ordinária (KO) é um interpolador de mínimos quadrados, mais utilizado em ciência do solo. Porém, ela suaviza os detalhes locais da variação espacial, superestimando pequenos valores e subestimando altos valores. Por isso, ela revela-se inadequada na avaliação da verdadeira variabilidade espacial dos óxidos de ferro. Embora a krigagem mostre a melhor estimativa de um atributo Z, ele não representa bem a variação. Deste modo, a alternativa é simulação geoestatística que avalia e quantifica a incerteza de um atributo, de maneira mais realista. A técnica de simulação estocástica mais utilizada é a simulação sequencial gaussiana (SSG), por ser, rápida e direta na construção da função de densidade de probabilidade acumulada condicional (f.d.p.a.c), sendo, portanto preferível à estimação pela KO. Desta forma, é importante testar outros métodos para caracterizar espacial dos óxidos de ferro. Objetivando avaliar o desempenho da (KO), krigagem ordinária dos dados padronizados (KOP) e da simulação seqüencial gaussiana (SSG) da variabilidade espacial dos óxidos de ferro em uma área com pedoformas: côncava e convexa foram coletados 121 amostras de duas malhas nos dois relevos classificados como: côncavo e convexo com espaçamento de 10 metros. O erro médio, o erro quadrático médio e o erro quadrático médio padronizado foram os critérios de avaliação da acurácia da predição. Os valores altos dos coeficientes de variação dos óxidos de ferro afetaram o desempenho dos métodos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Iron oxides are important environmental indicators and have great influence on the physical and chemical properties of soil. However, for a better understanding of their formation and occurrence studies are necessary spatial variability. Geostatistics is a tool for this study, ordinary kriging (OK) is a least squares interpolator, is the most widely used in soil science. However smooths out local details of spatial, small values overestimating and underestimating high values. Therefore, is inadequate in the evaluation of iron oxides. Although the kriging show the best estimate of an attribute Z, it does not represent well the variation. Thus, the alternative is geroestatisctical simulation that evaluates and quantify the uncertainty of an attribute, more realistically. Since the most widely used is the sequential Gaussian simulation (SGS), to be quickly and directly in the construction of the density function of cumulative probability (fdpac), and are preferred to the estimation. Thus, is important to test other methods to characterize spatially of iron oxides. In order to evaluate the performance of (OK), ordinary kriging of standardized data (OKS) and sequential Gaussian simulation (SGS) of the spatial variability of iron oxides in an area with landform: concave and convex 121 samples were collected data in two loops with two reliefs classified as concave and convex with spacing of 10 meters. The average error, the mean square error and root mean square error were standardized criteria for evaluating the accuracy of prediction. High values of coefficient of variation of iron oxides harmed the performance of the methods. The landforms showed variable differentiated by SGS. The maps of OKS and E-type had higher accuracy and greater detail in relation to landforms in the OK. It is recommended that E-type maps instead of maps OK... (Complete abstract click electronic access below) / Mestre

Soil physical and chemical properties determine a soil's crop production potential and the sustainability of a production system. The objective of this study was to determine the effect of solid and liquid pig manure application on the physical and chemical properties of soil after 5 years of manure application. Solid pig manure increased saturated hydraulic conductivity (Ksat) by 110%, aggregate stability by 30%, available and total phosphorus by 471% and 52% respectively, available nitrogen by 38%, organic carbon by 29% and exchangeable K by 308%, and reduced soil bulk density by 14%. Liquid pig manure (LPM) also increased aggregate stability by 21%, exchangeable K by 45%, available P and total P by 258% and 27%, respectively and, reduced bulk density by 6%. An important finding was the 33% decrease in the concentration of exchangeable Ca in LPM-amended soils. Significant manure by cropping system interaction was also obtained for water retention parameters and available water, total nitrogen and electrical conductivity. There was no effect of pig manure on pH and exchangeable Mg concentrations. Soils under perennial vegetation had 31% greater Ksat, 26% increase in available N, 31% greater available P, 15% greater total P and 12% lower bulk density compared with those under annual crops. Our results show that SPM has a potential as a better organic amendment in improving physical and chemical properties of surface soils. / February 2016

Orientador: Ricardo Antonio Ferreira Rodrigues / Banca: Marlene Cristina Alves / Banca: Jolimar Antonio Schiavo / Resumo: Reduzir as variações térmicas do solo com a cobertura vegetal favorece o armazenamento de água e aumento nos teores de matéria orgânica e nutrientes disponíveis às plantas. Este trabalho teve por objetivo avaliar a temperatura e alguns atributos físicos e químicos de um Latossolo em recuperação com adubos verdes, gramínea e lodo de esgoto, cultivado com Gonçalo-alves. O experimento foi realizado em área de empréstimo no município de Selvíria/MS. O delineamento experimental foi em blocos com cinco tratamentos e cinco repetições, os tratamentos foram: Solo Exposto (testemunha); espécie arbórea Gonçalo-alves; Gonçalo-alves + crotalária; Gonçalo-alves + feijão-de-porco; Gonçalo-alves + braquiária (Brachiaria decumbens) + lodo (60 t ha-1), e comparadas com uma condição natural de Cerrado (mata adjacente). No tratamento com Gonçalo-alves + braquiária + lodo os valores de P-resina foram elevados em todas as camadas, proporcionando incrementos de Ca+2 e Mg+2 e elevação da CTC, evidenciando os efeitos do lodo como fertilizante. Não foram observadas contribuições dos adubos verdes sobre a fertilidade do solo, apenas sobre a macroporosidade do solo. Houve melhor estruturação do solo com aumento do tamanho e da estabilização de agregados em água, na superfície para Gonçalo-alves + braquiária + lodo, assim como maior diâmetro médio ponderado de agregados, semelhante ao solo de Cerrado. A umidade do solo foi maior no Cerrado e em Gonçalo-alves + braquiária + lodo com cobertura vegetal permanente. O efeito da gramínea foi capaz de reduzir a temperatura do solo na superfície, principalmente para o verão. A capacidade térmica do solo foi maior para todos os tratamentos em relação ao Cerrado. Foi observado para todos os tratamentos correlação positiva entre a capacidade térmica (seco e úmido)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Reduce the temperature variations of the soil with plant cover promotes the storage of water and increase in soil organic matter and nutrients available to plants. This study aimed to evaluate the temperature and some physical and chemical attributes of a soil in recovery with green manure, sewage sludge and grass, grown with Gonçalo-alves. The experiment was carried out on loan in Selvíria/MS. The experiment was arranged in blocks with five treatments and five replicates, the treatments were: Bare Soil (control) tree species Gonçalo- alves; Gonçalo-alves + sunn; Gonçalo-alves + jack bean ; Gonçalo-alves + Brachiaria (Brachiaria decumbens) + sludge (60 t ha-1), and compared to a natural condition of Cerrado (adjacent forest). In dealing with Gonçalo-alves + Brachiaria + sludge silt values Brachiaria resin-P were elevated in all layers, providing increments of Ca+2 and Mg+2 and elevation of CEC, showing the effects of sludge as fertilizer. There were no contributions from the green manures on soil fertility, only on the soil macroporosity. There was a better soil structure with increasing size and the stabilization of aggregates in water, surface-to Goncalo alves Brachiaria + + sludge, and increased mean weight diameter of aggregates, similar to the Cerrado soil. Soil moisture was higher in the Cerrado and Gonçalo-alves Brachiaria + Brachiaria + sludge with permanent vegetative cover. The effect of grass was able to reduce the soil temperature at the surface, especially for the summer. The heat capacity of soil was higher for all treatments in relation to Savannah. Was observed for all treatments positive correlation between the heat capacity (dry and wet) and bulk density. The temperature was positively correlated with soil bulk density only in treatments with Gonçalo-Alves, Gonçalo- alves + sunn and Gonçalo-alves + bean pork... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:29:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-03Bitstream added on 2014-06-13T19:59:37Z : No. of bitstreams: 1 miranda_lpm_me_ilha.pdf: 888557 bytes, checksum: 41f469c8fa9f02799dda33c0cf0a2f89 (MD5) / Reduzir as variações térmicas do solo com a cobertura vegetal favorece o armazenamento de água e aumento nos teores de matéria orgânica e nutrientes disponíveis às plantas. Este trabalho teve por objetivo avaliar a temperatura e alguns atributos físicos e químicos de um Latossolo em recuperação com adubos verdes, gramínea e lodo de esgoto, cultivado com Gonçalo-alves. O experimento foi realizado em área de empréstimo no município de Selvíria/MS. O delineamento experimental foi em blocos com cinco tratamentos e cinco repetições, os tratamentos foram: Solo Exposto (testemunha); espécie arbórea Gonçalo-alves; Gonçalo-alves + crotalária; Gonçalo-alves + feijão-de-porco; Gonçalo-alves + braquiária (Brachiaria decumbens) + lodo (60 t ha-1), e comparadas com uma condição natural de Cerrado (mata adjacente). No tratamento com Gonçalo-alves + braquiária + lodo os valores de P-resina foram elevados em todas as camadas, proporcionando incrementos de Ca+2 e Mg+2 e elevação da CTC, evidenciando os efeitos do lodo como fertilizante. Não foram observadas contribuições dos adubos verdes sobre a fertilidade do solo, apenas sobre a macroporosidade do solo. Houve melhor estruturação do solo com aumento do tamanho e da estabilização de agregados em água, na superfície para Gonçalo-alves + braquiária + lodo, assim como maior diâmetro médio ponderado de agregados, semelhante ao solo de Cerrado. A umidade do solo foi maior no Cerrado e em Gonçalo-alves + braquiária + lodo com cobertura vegetal permanente. O efeito da gramínea foi capaz de reduzir a temperatura do solo na superfície, principalmente para o verão. A capacidade térmica do solo foi maior para todos os tratamentos em relação ao Cerrado. Foi observado para todos os tratamentos correlação positiva entre a capacidade térmica (seco e úmido)... / Reduce the temperature variations of the soil with plant cover promotes the storage of water and increase in soil organic matter and nutrients available to plants. This study aimed to evaluate the temperature and some physical and chemical attributes of a soil in recovery with green manure, sewage sludge and grass, grown with Gonçalo-alves. The experiment was carried out on loan in Selvíria/MS. The experiment was arranged in blocks with five treatments and five replicates, the treatments were: Bare Soil (control) tree species Gonçalo- alves; Gonçalo-alves + sunn; Gonçalo-alves + jack bean ; Gonçalo-alves + Brachiaria (Brachiaria decumbens) + sludge (60 t ha-1), and compared to a natural condition of Cerrado (adjacent forest). In dealing with Gonçalo-alves + Brachiaria + sludge silt values Brachiaria resin-P were elevated in all layers, providing increments of Ca+2 and Mg+2 and elevation of CEC, showing the effects of sludge as fertilizer. There were no contributions from the green manures on soil fertility, only on the soil macroporosity. There was a better soil structure with increasing size and the stabilization of aggregates in water, surface-to Goncalo alves Brachiaria + + sludge, and increased mean weight diameter of aggregates, similar to the Cerrado soil. Soil moisture was higher in the Cerrado and Gonçalo-alves Brachiaria + Brachiaria + sludge with permanent vegetative cover. The effect of grass was able to reduce the soil temperature at the surface, especially for the summer. The heat capacity of soil was higher for all treatments in relation to Savannah. Was observed for all treatments positive correlation between the heat capacity (dry and wet) and bulk density. The temperature was positively correlated with soil bulk density only in treatments with Gonçalo-Alves, Gonçalo- alves + sunn and Gonçalo-alves + bean pork... (Complete abstract click electronic access below)

Applications of fertilizers derived from non-renewable resources, along with improved land management practices have contributed greatly increased crop yields in the past 70 years. Biofertilizers and organic amendments, provide alternative sources of nutrients for increased plant yields and resistance against abiotic stress. The objective of this work was to evaluate the effectiveness of various biofertilizers and an organic amendment on improve plant health and/or crop yield. The first study focused on the organic amendment, glucoheptonate and found that applications of 800-1600 kg/ha can increase available water capacity in fine textured soils by up to 3%. The second study evaluated the effectiveness of dual-inoculating biofertilizers Mung beans (Vigna radiata (L.) Wilczek) with two, bradyrhizobium spp. and arbuscular mycorrhizal fungi. Dual inoculation significantly increased grain yield (+33%) compared to a synthetic N fertilizer application but did not significantly increase grain yield compared to the control (+22%). Dual inoculation may increase grain yields of mung beans compared to synthetic fertilizer regime but does not show evidence of improving N fixation. The final study was a greenhouse experiment focused on evaluating some mung bean cultivars to determine their susceptibility to salt stress while also evaluating the effect of inoculation in combating saline soils. Germination was significantly decreased at 6 dS/m in all cultivars by about 36% when compared to the control treatment (0 dS/m). Seed yields, pods per plant and seeds per plant, increased as salt concentration increased. No factors recorded where affected by inoculation. Overall, our research suggests that the use of biofertilizers and organic amendments can improve crop health, but other management and environmental considerations need to be accounted for when reporting effectiveness of such alternative soil amendments / Doctor of Philosophy / Applications of fertilizers derived from non-renewable resources, along with improved land management practices have contributed greatly to increased crop yields in the past 70 years. Biofertilizers and organic amendments, provide alternative sources of nutrients for increased plant yields and resistance against abiotic stress. The objective of this work was to evaluate the effectiveness of an organic amendment and various biofertilizers to improve plant health and/or crop yield. The first study focused on the organic amendment, glucoheptonate and found that applications of 800-1600 kg/ha can increase available water capacity in fine textured soils by up to 3%. The second study evaluated the effectiveness of dual-inoculating Mung beans (Vigna radiata (L.)Wilczek) with two biofertilizers, bradyrhizobium spp. and arbuscular mycorrhizal fungi. Dual inoculation significantly increased grain yield (+33%) compared to a synthetic N fertilizer application but did not significantly increase grain yield compared to the control (+22%). Dual inoculation may increase grain yields of mung bean compared to synthetic fertilizer regime but does not show evidence of improving N fixation. The final study was a greenhouse experiment focused on evaluating mung bean cultivars (4) to determine their susceptibility to salt stress while also evaluating the effect of inoculation in combating the effect of saline soils. Germination was significantly decreased by about 36% at a salinity of 6 dS/m across all cultivars compared to the control at 0 dS/m. Seed yields, pods per plant and seeds per plant, increased as salt concentration increased for some cultivars. No factors recorded were observed to be affected by inoculation. Overall, our research suggests that the use of biofertilizers and organic amendments can improve crop health, but other management and environmental considerations need to be accounted for when reporting effectiveness of such alternative soil amendments.

A compactação do solo tem sido objeto de estudo devido a utilização mais freqüente e intensa da mecanização e devido a sua influência negativa na qualidade física do solo às culturas. Os efeitos da compactação sobre a deterioração da estrutura do solo dependem de vários fatores, como, a textura, o conteúdo de carbono orgânico, o conteúdo de água no solo durante as operações de campo e a freqüência e intensidade da carga aplicada pelas máquinas e implementos utilizados no campo. Estes fatores são os responsáveis pelos diferentes níveis de compactação encontrados nos solos agrícolas, sendo que a influência destes é de importância fundamental para o desenvolvimento de estratégias que evitem ou pelo menos amenizem a compactação no perfil do solo. Neste sentido, este trabalho teve por objetivos (i) analisar os efeitos de diferentes níveis de carga de máquinas aplicados no solo sobre as propriedades físicas do solo; (ii) determinar propriedades físicas do solo em camadas superficiais e subsuperficiais de um solo cultivado por longo prazo em sistema de plantio direto; (iii) avaliar a qualidade física do solo através do parâmetro S; (iv) comparar as predições da pressão de preconsolidação estimada por diferentes métodos de ajuste com uma ampla variação textural do solo. Para isso, foi realizado um estudo de campo, conduzido em quatro experimentos na Suécia com tráfego de máquinas, onde diferentes pressões foram detectadas por sensores colocados em diferentes profundidades no solo, assim como a análise da densidade do solo e da resistência à penetração. Em outro estudo, propriedades dinâmicas e estáticas foram determinadas em diferentes camadas de um solo cultivado sob sistema de plantio direto há 14 anos, analisando a qualidade física do solo. E por final, a análise comparando diferentes métodos de ajuste para pressão de preconsolidação foi realizada. As propriedades físicas do solo refletiram os efeitos das cargas aplicadas no solo, demonstrando aumento da densidade do solo e da resistência à penetração. As propriedades estáticas do solo demonstraram a existência de uma camada mais densa no perfil do solo, porém as propriedades dinâmicas apresentaram resultados satisfatórios na mesma camada. A qualidade do solo avaliada pelo parâmetro S indicou que o solo possui boa estrutura física em todas as camadas estudadas. As comparações entre métodos de ajuste para a pressão de preconsolidação indicaram que superestimativas e subestimativas podem ocorrer quando se usa métodos diferentes, tornando difícil o uso de um valor absoluto de pressão de preconsolidação como um limite para as pressões exercidas no solo a fim de evitar a compactação do mesmo. / Soil compaction has been the subject of study for many years due to its implications for crop yield. Its effect on the deterioration of the soil structure depend on several factors, such as, soil texture, organic carbon content, water content during the field operations as well, the frequency and intensity of the load applied by the machines and implements used in the field. These factors are the responsible for the different levels of compaction found in the soil agricultural, and their effects are very importance for the development of strategies to avoid or to ameliorate the soil compaction in the soil profile. In this sense, this work took as objectives (i) to analyse the effects of different levels of load machines applied on the soil physical properties; (ii) to determine soil physical properties on topsoil and subsoil layers cultivated under no-tillage system; (iii) to evaluate the soil physical quality by S parameter; (iv) to compare the predictions of the precompression stress fitted by different methods ranging several soil textural classes. Then, it was carried out a field study, performed in four experiments in Sweden with machine traffic. Different load pressures were detected by sensors put in different depths in the soil, and also the bulk density and penetration resistance were determined. Another study, dynamic and static properties were determined in different soil layers under no-tillage. Besides that the soil physical quality was verified. Finally, comparisons between precompression stress fitted by different methods was done. The soil physical properties reflected the effects of loads applied on soil, demonstrating increase of the soil bulk density and of the penetration resistance. The soil static properties demonstrated to exist a denser layer in the soil profile, however the dynamic properties presented satisfactory results in the same layer. Soil physcal quality evaluated by the S parameter indicated a good soil physical structure in all the studied layers. The comparisons showed that the choice of method had a significant influence on the precompression stress values, becoming difficult the use of an absolute value of it, as a limit for the load pressures applied on soil to avoid the soil compaction.

A compactação do solo tem sido objeto de estudo devido a utilização mais freqüente e intensa da mecanização e devido a sua influência negativa na qualidade física do solo às culturas. Os efeitos da compactação sobre a deterioração da estrutura do solo dependem de vários fatores, como, a textura, o conteúdo de carbono orgânico, o conteúdo de água no solo durante as operações de campo e a freqüência e intensidade da carga aplicada pelas máquinas e implementos utilizados no campo. Estes fatores são os responsáveis pelos diferentes níveis de compactação encontrados nos solos agrícolas, sendo que a influência destes é de importância fundamental para o desenvolvimento de estratégias que evitem ou pelo menos amenizem a compactação no perfil do solo. Neste sentido, este trabalho teve por objetivos (i) analisar os efeitos de diferentes níveis de carga de máquinas aplicados no solo sobre as propriedades físicas do solo; (ii) determinar propriedades físicas do solo em camadas superficiais e subsuperficiais de um solo cultivado por longo prazo em sistema de plantio direto; (iii) avaliar a qualidade física do solo através do parâmetro S; (iv) comparar as predições da pressão de preconsolidação estimada por diferentes métodos de ajuste com uma ampla variação textural do solo. Para isso, foi realizado um estudo de campo, conduzido em quatro experimentos na Suécia com tráfego de máquinas, onde diferentes pressões foram detectadas por sensores colocados em diferentes profundidades no solo, assim como a análise da densidade do solo e da resistência à penetração. Em outro estudo, propriedades dinâmicas e estáticas foram determinadas em diferentes camadas de um solo cultivado sob sistema de plantio direto há 14 anos, analisando a qualidade física do solo. E por final, a análise comparando diferentes métodos de ajuste para pressão de preconsolidação foi realizada. As propriedades físicas do solo refletiram os efeitos das cargas aplicadas no solo, demonstrando aumento da densidade do solo e da resistência à penetração. As propriedades estáticas do solo demonstraram a existência de uma camada mais densa no perfil do solo, porém as propriedades dinâmicas apresentaram resultados satisfatórios na mesma camada. A qualidade do solo avaliada pelo parâmetro S indicou que o solo possui boa estrutura física em todas as camadas estudadas. As comparações entre métodos de ajuste para a pressão de preconsolidação indicaram que superestimativas e subestimativas podem ocorrer quando se usa métodos diferentes, tornando difícil o uso de um valor absoluto de pressão de preconsolidação como um limite para as pressões exercidas no solo a fim de evitar a compactação do mesmo. / Soil compaction has been the subject of study for many years due to its implications for crop yield. Its effect on the deterioration of the soil structure depend on several factors, such as, soil texture, organic carbon content, water content during the field operations as well, the frequency and intensity of the load applied by the machines and implements used in the field. These factors are the responsible for the different levels of compaction found in the soil agricultural, and their effects are very importance for the development of strategies to avoid or to ameliorate the soil compaction in the soil profile. In this sense, this work took as objectives (i) to analyse the effects of different levels of load machines applied on the soil physical properties; (ii) to determine soil physical properties on topsoil and subsoil layers cultivated under no-tillage system; (iii) to evaluate the soil physical quality by S parameter; (iv) to compare the predictions of the precompression stress fitted by different methods ranging several soil textural classes. Then, it was carried out a field study, performed in four experiments in Sweden with machine traffic. Different load pressures were detected by sensors put in different depths in the soil, and also the bulk density and penetration resistance were determined. Another study, dynamic and static properties were determined in different soil layers under no-tillage. Besides that the soil physical quality was verified. Finally, comparisons between precompression stress fitted by different methods was done. The soil physical properties reflected the effects of loads applied on soil, demonstrating increase of the soil bulk density and of the penetration resistance. The soil static properties demonstrated to exist a denser layer in the soil profile, however the dynamic properties presented satisfactory results in the same layer. Soil physcal quality evaluated by the S parameter indicated a good soil physical structure in all the studied layers. The comparisons showed that the choice of method had a significant influence on the precompression stress values, becoming difficult the use of an absolute value of it, as a limit for the load pressures applied on soil to avoid the soil compaction.

Made available in DSpace on 2014-06-11T19:29:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-27Bitstream added on 2014-06-13T21:00:06Z : No. of bitstreams: 1 lima_cgr_me_ilha.pdf: 1824427 bytes, checksum: 2c8f6de8a9b1cf06bd3d4c3b5302f56f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O milho é um dos cereais mais cultivados e consumidos no mundo. Para silagem é a forrageira de melhor qualidade, muito utilizada na alimentação bovina. Por apresentar sistema radicular com alto potencial de desenvolvimento, os atributos físicos do solo são de extrema importância à sua produtividade, uma vez que, em condições adversas, podem dificultar a penetração das raízes e, conseqüentemente, limitar o adequado aproveitamento dos nutrientes e da água disponível. No ano agrícola de 2005, na Fazenda Bonança (Agropecuária Dahma), município de Pereira Barreto (SP), Brasil (20o40’12’’ latitude S; 51o01’50’’ longitude W), foram analisadas a produtividade de forragem do milho safrinha outonal (MSF), no sistema plantio direto irrigado, as densidades da partícula (DP) e do solo (DS), as porosidades totais determinada (PT) e calculada (PTc), os teores de areia (AR), silte (SI) e de argila (AR) de um Latossolo Vermelho Distrófico (Acrustox Háplico) local, nas profundidades 1 (0-0,10 m), 2 (0,10-0,20 m) e 3 (0,20-0,30 m). O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para a produtividade da forragem. Foi instalada a malha geoestatística para a coleta dos dados do solo e da planta, contendo 125 pontos amostrais, numa área de 2500 m2 e declive homogêneo de 0,025 m/m. No geral, os atributos estudados, além de não terem revelado distribuição aleatória, apresentaram variabilidade entre média e baixa. Seguiram padrões espaciais claramente definidos, com alcances da dependência espacial entre 6,8 e 46,8 metros. Assim, o maior alcance que poderá assegurar extrema semelhança em magnitude para qualquer atributo estudado, e que poderá alimentar os pacotes... / Corn is one of cereals most cropped and consumed in the world. At silage is the best green crop, very employed in the bovine nutrition. Once it has roots with high growth capability, the soil physical attributes are very important to his productivity, so that, in adverse conditions, they can inhibit the roots penetration, and thus restrict the suitable absorption of plant nutrients and available water. The forage productivity of autumnal corn (FP) in no-tillage and irrigated, and the particle (PD) and bulk (BD) densities, the determined (TPd) and computed (TPc) total porosities, the contents of sand (SA), silt (SI), and clay (CL) soil attributes, in depths 1 (0-0,10 m), 2 (0,10-0,20 m), and 3 (0,20-0,30 m), in a Haplic Acrustox of Bonança Farm (Dahma Agricultural Company) in Pereira Barreto County, Sao Paulo State, Brazil (20o40’12’’ latitude S; 51o01’50’’ longitude W), were analyzed in the agricultural year of 2005. The purpose was to study the variability and linear spatial correlations among the attributes (plant and soil), aiming to select an index of soil physical quality with good capacity to represent the forage productivity. A grid geostatistical to collect soil and plant data was installed, with one hundred and twenty five sample points, in a area of 2500 m2, with homogeneous slope steepness of 0.025 m/m. Yonder not changed randomly, the studied attributes showed median to low variability, with excellent spatial performances, and ranges between 6.8 and 46.8 meters. Therefore, the farthermost range at to guarantee high similitude in size, at every-one soil researched attribute, and however it will be used in the computational software of precision agriculture, must be of 46.8 meters. The FP will be estimated through equation of multiple linear regression, from the TPd1 and TPd2 attributes. The Core Method must determine the TP advantageous. Although the ...(Complete abstract click electronic access below)