A cama de semeadura é uma das principais condições físicas do solo para crescimento das plantas. A avaliação da qualidade física desse ambiente do solo, onde ocorre a germinação e emergência das culturas, é de fundamental importância para compreender os fatores que afetam o seu desenvolvimento. A presente pesquisa foi realizada, inicialmente, no Brasil, com o objetivo de avaliar a qualidade física da cama de semeadura do solo, pela determinação de propriedades estruturais e físico-hídricas do solo, e parâmetros de emergência das culturas milho e soja em sistema plantio direto de longa duração submetido à escarificação mecânica e biológica do solo. O trabalho foi desenvolvido em área pertencente à Universidade Estadual de Ponta Grossa, Paraná. Os tratamentos avaliados foram: sistema plantio direto por 16 anos, sistema plantio direto submetido à escarificação mecânica até 0,25 m de profundidade e sistema plantio direto submetido à escarificação biológica por meio do nabo forrageiro. As amostragens de solos foram realizadas aos seis e 18 meses após a implantação dos tratamentos, correspondentes às semeaduras das culturas do milho (Outubro de 2009) e da soja (Novembro de 2010) nas camadas 0-5 e 5-10 cm de profundidade. Para o experimento desenvolvido nos Estados Unidos, o objetivo foi avaliar a qualidade física da cama de semeadura do solo, pela determinação do intervalo hídrico ótimo, e parâmetros de emergência da cultura do trigo, em dois experimentos de longa duração que envolveu sistemas de cultivo e sistemas de preparo do solo. Esses experimentos foram conduzidos em área da Kansas State University, em Hays, Kansas, EUA. Os sistemas de preparo do solo envolveram a rotação trigo/sorgo/pousio sob o preparo convencional, reduzido e plantio direto implantados há 46 anos. Os sistemas de cultivo consistiram das sucessões trigo/pousio, trigo/sorgo/pousio e trigo/trigo manejadas sob preparo reduzido e plantio direto, implantados há 35 anos. A amostragem do solo foi realizada na cama de semeadura do trigo (Outubro/Novembro de 2011) nas camadas 0-5 e 5-10 cm de profundidade. Os dados foram submetidos à análise de variância e, quando significativos, as médias dos tratamentos foram comparadas pelo teste Tukey. Os resultados do estudo feito no Brasil demonstraram que a escarificação mecânica apresentou um baixo efeito residual sobre as propriedades físicas do solo, indicando ser desnecessária sua aplicação com vistas a melhorar a qualidade física do solo. A cultura do nabo forrageiro, como alternativa de escarificação biológica, pode ser incluída no sistema de rotação de culturas, uma vez que se mostrou eficiente em melhorar algumas propriedades físicas do solo. No estudo realizado nos EUA, no experimento sobre sistemas de preparo, o preparo reduzido resultou em melhor condição física da cama de semeadura do solo. O preparo convencional foi o tratamento que apresentou uma condição física do solo menos favorável ao crescimento inicial das plantas. O sistema de cultivo trigo/trigo sob preparo reduzido apresentou o melhor IHO da cama de semeadura. O procedimento boundary line demonstrou que os parâmetros de emergência das culturas foram dependentes das propriedades físicas da cama de semeadura do solo. / The seedbed is one of the most important soil physical conditions for plant growth. The evaluation of the soil physical quality in such soil environment is essential to understand the factors that affect crop development, as it is where seed germination and plant emergence and establishment take place. The objective of the experiment carried out in Brazil was to evaluate: the physical quality of the soil seedbed by the determination of its structural and physical-hydric properties; and the emergence parameters of the corn and soybean crops under long-term no tillage submitted to mechanical and biological chiseling. This experiment was carried out in Ponta Grossa, Paraná State, Brazil, at the farm-school belonging to Ponta Grossa State University. The treatments were no-tillage for 16 years, no-tillage submitted to mechanical chiseling at 0.25 m soil depth and no-tillage submitted to biological chiseling by a forage radish crop. Soil samples were collected at six and 18 months after the treatments were implemented, corresponding to a maize seedbed (October 2009) and a soybean seedbed (November 2010), for the 0 to 5 and 5 to 10 cm soil depths. For the experiments developed in the United States, the objective was to evaluate: the physical quality of the soil seedbed by the least limiting water range determination; and the wheat emergence parameters from two longterm experiments involving different cropping systems (35 years) and soil tillage systems (46 years). These experiments were conducted in an area belonging to Kansas State University located in Hays, Kansas, USA. The tillage systems experiment consisted of a wheat/sorghum/fallow rotation under conventional, reduced and no tillage. The cropping systems experiment consisted of wheat/fallow, wheat/sorghum/fallow and wheat/wheat rotations cultivated under reduced and no tillage. Soil samples were collected from the wheat seedbed (October/November 2011) at the 0 to 5 and 5 to 10 cm soil depths. The data were submitted to the variance analysis and, when significant, the means were compared by the Tukey test. The results from the experiment performed in Brazil showed that the mechanical chiseling had a lower residual effect on the soil physical properties, indicating that it is unnecessary when the aim is to improve the soil physical quality. The forage radish cultivation, as an alternative of biological chiseling, can be included in the crop rotation system once it was efficient at improving some soil physical properties. For the tillage systems experiment, which was conducted in the United States, the reduced tillage treatment resulted in a better physical condition of the soil seedbed. The conventional tillage was the treatment that presented the least favorable soil physical condition for the initial plant growth. The wheat/wheat cropping system under reduced tillage showed the best least limiting water range of the soil seedbed. The boundary line approach demonstrated that the crop emergence parameters were dependent on the physical properties of the soil seedbed.

Orientador: Maria Helena Moraes / Banca: Roberto Lyra Villas Bôas / Banca: Itamar Andrioli / Banca: Ricardo Ralish / Banca: Itamar Rosa Teixeira / Resumo: O presente trabalho teve como objetivo avaliar o efeito da utilização de adubos orgânicos, produzidos por diferentes processos de reciclagem de dejetos bovinos criados em sistema de confinamento para novilhos superprecoces, nos atributos químicos e físicos de um LATOSSOLO VERMELHO Distrófico e na produtividade da cultura do milho. O experimento foi conduzido por duas safras agrícolas, 2002/2003 e 2003/2004. Utilizou-se o delineamento experimental em blocos casualizados com quatro repetições e seis tratamentos: T1 = efluente de biodigestor; T2 = esterco de esterqueira; T3 = composto orgânico; T4 = vermicomposto; T5 = adubo mineral; T6 = testemunha (sem utilização de adubos). As parcelas possuíam 15 m de comprimento por 8 m de largura, com área total de 120 m2. As quantidades para cada fonte orgânica foram calculadas com base nos seus teores de nitrogênio, para aplicação de 120 kg ha-1 de N. No tratamento T5 utilizou-se uma formulação N-P2O5-K2O, com base na análise do solo para P e K, e também 120 kg ha-1 de N, dos quais 30 kg foram aplicados na base e o restante em cobertura, em uma única aplicação, aos 33 e 37 dias após a emergência das plantas, na primeira e segunda safra, respectivamente. Os adubos orgânicos foram incorporados ao solo por meio de uma gradagem, antes da semeadura. O milho, cv. híbrido DKB 350 foi semeado dia 6 de janeiro de 2003 na primeira safra, e no dia 26 de dezembro de 2003 na segunda safra, com espaçamento de 90 cm entre linhas, e população de 55000 plantas por hectare. Os atributos do solo foram avaliados nas camadas de 0-0,10 e 0,10-0,20 e 0,20-0,30 m. Os atributos físicos avaliados foram o diâmetro médio ponderado, a argila dispersa em água, a resistência à penetração, a condutividade hidráulica saturada, a densidade do solo, porosidade total, macro e microporosidade...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work had as its aim to evaluate the effect of cattle manure usage, produced by different processes of bovine dejections recycling raised in pen system for superprecocious steers in the chemical and physical properties of a distrophyc Red Oxisol and in the maize productivity. The experiment was carried out by two crop harvests 2002/2003 and 2003/2004. A completely randomized block design was used with four replications and six treatments: T1 = biodigestor effluent; T2 = cattle manure; T3 = organic composition; T4 = vermicompost; T5 = mineral fertilizer; T6 = witness (without fertilizer application). The parcels were 15 meters long and 8 meters wide, with a total area of 120 square meters. The amounts for each organic source had been calculated based on their nitrogen concentration, for a N application of 120 kg ha-1. In T5 treatment, a N-P2-O5-K2O formula was used, based on the soil analysis for P and K, and also 120 kg ha-1 of N, of which 30 kg were applied in the base and the rest in the covering, in a single application, at 33 and 37 days after the plant emerging, in the first and second harvests, respectively. The organic matter had been incorporated to the soil by grading, before sowing. The maize, cv. Hybrid DKB 350 was sown in January 6th, 2003 in the first harvest and in December 26th, 2003 in the second harvest, with a distance of 90 cm between the lines and a population of 55,000 plants per linear meter. The soil attributes were evaluated in the 0-0,10 and 0,10-0,20 and 0,20-0,30 layers. The evaluated physical attributes were the mean weighed diameter, the water dispersed clay, the penetration resistance, the saturated hydraulic conductivity, the soil bulk density, total porosity, macro and microporosity. Concerning the chemical attributes, the fractioned organic matter, macro and micronutrients, pH... (Complete abstract, click eletronic address below) / Doutor

As crostas são o resultado da degradação da estrutura superficial dos solos, favorecem a erosão e a degradação ambiental dos solos. Este estudo avaloiu a dinâmica da formação de crostas superficiais e as consequencias sobre a porosidade, condutividade hidráulica (K), retenção de água, densidade (Ds) e a rugosidade de um Argissolo Vermelho amarelo conduzido com diferentes sistemas de preparo do solo e aplicação de lâminas de chuva simulada. Avaliou-se também, através de um experimento em laboratório, os processos envolvidos na quebra dos agregados, sob chuvas simuladas. O experimento foi conduzido, nos anos de 2009 e 2010. Em parcelas de 15 x 30 m foram conduzidos os diferentes preparos do solo: preparo convencional (PC), preparo reduzido (PR) e sem preparo (SP). Dentro das parcelas instalou-se micro-parcelas de 1m x 1m, onde foram aplicadas diferentes lâminas de chuva simulada (0, 27, 54 e 80 mm) com intensidade de 80 mm h-1. Foram realizadas coletas de dados de rugosidade, medidas de K, coleta de amostras indeformadas de solo para análise da porosidade e confecção de lâminas delgadas, e também anéis cilíndricos para curva de retenção de água (CRA) e Ds do solo. No experimento de laboratório, utilizou-se dois solos (siltoso e argiloso) e duas classe de agregados (1-3 e 3-5 mm). Os agregados foram submetidos a diferentes chuvas simuladas (28mmh-1 + EC forte; 28mmh-1 + EC fraca; 90mmh-1 + EC forte; 90mmh-1 + EC fraca) e após avaliou-se o diâmetro médio ponderado dos agregados (DMP). A dinâmica da formação de crostas ocorreu de maneira diferenciada em ambos os sistemas de preparo. Nos sistemas de PC e PR a maior redução da porosidade, pelo efeito da chuva aplicada, ocorreu na camada da crosta e no sistema SP na camada da subcrosta. A camada da crosta foi responsável pela redução da porosidade e K, e aumento da Ds nos sistemas PC e PR. As maiores umidades volumétricas observadas nas CRA ocorreram no sistema de PR e as menores no PC e não demonstraram evolução entre as chuvas aplicadas. A rugosidade superficial do solo variou em função dos sistemas de preparo realizados. Os sistemas conservacionistas (PR e SP) apresentaram maior rugosidade no primeiro ano, no segundo ano a maior rugosidade foi observada no sistema SP. O PC demonstrou nos dois anos estudados a mesma tendência, em função das chuvas aplicadas, inicialmente ocorreu um aumento na rugosidade até uma chuva máxima diminuindo em seguida. No experimento em laboratório, as maiores reduções no DMP ocorreram até a lâmina de 3 e 2 mm para o solo argiloso e siltoso, respectivamente. Nas quantidades iniciais de chuva (lâminas iniciais) a intensidade foi determinante na redução do DMP, com o aumento da quantidade de chuva a energia cinética (EC) passou a influenciar a redução do DMP. A intensidade de 28 mm h-1 promoveu as maiores reduções do DMP possivelmente pelo maior tempo de exposição dos agregados ao molhamento. / The crusts are the result of degradation of the surface structure of the soil, favoring erosion and environmental degradation of soils. This study evaluated the dynamics of the develop surface crusts and its consequences on the porosity, hydraulic conductivity (K), water retention, bulk density (Ds) and the roughness of a Typic Hapludult conducted with different systems of tillage and application of sheets simulated rainfall. Was also evaluated through the an laboratory experiment, the processes involved in the breakdown of aggregates under simulated rainfall. The experiment was conducted in the years 2009 and 2010. In plots of 15 x 30 m were installed the soil tillage: conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). Inside of the plots was installed micro-plots of 1m x 1m, which were applied different sheets of simulated rainfall (0, 27, 54 and 80 mm) with intensity of 80 mm h-1. Roughness data, K measurements, sampling of undisturbed soil samples for porosity analysis and preparation of thin sections, and also cylindrical rings for water retention curve (SWRC) and Ds, were collected. In the laboratory experiment two soils (Silt Loam and Clay Loam) and two aggregate classes (1-3 and 3-5 mm) were used. The aggregates were submitted to different simulated rainfall (28mmh-1 + KE strong; 28mmh-1 + KE weak; 90mmh-1 + KE strong; 90mmh-1 + KE weak) and after the mean weight diameter (MWD) was evaluated. The dynamics of crust formation occurred differently in both tillage systems. In the CT and RT systems the major reduction of the porosity, by effect of the applied rainfall, occurred in the crust layer and in the NT system occurred in the subcrosta layer. Crust formation was responsible for reducing the porosity and K, and increasing Ds, in RT and CT systems. The higher volumetric moisture contents observed in CRA occurred in the PR system and the lowest in CT. The CRA did not show changes between the applied rainfall. The surface roughness of the soil varied in relation to the tillage systems. RT and NT systems showed a higher roughness in the first year during the second year a higher roughness was observed in the NT system. The CT in the two years studied showed the same trend of evolution according to of applied rainfall, initially there was an increase in roughness up to a maximum rain and then decrease. In the laboratory experiment, the largest DMP reductions occurred in the 3 and 2 mm rainfall for the Silt Loam and Clay Loam soils, respectively. In the initial amounts of rainfall, the intensity was determinant in the MWD reduction. With the increase in the amount of rainfall, the kinetic energy influences the MWD reduction. The intensity of 28 mm h-1 produced the greatest reductions in DMP, possibly due to the longer exposure of the aggregates to wetting.

Conduziu-se durante dois anos, em um Latossolo Vermelho Amarelo, em Piracicaba-SP (22o41’00" S; 47o39’00" O; 554 m de altitude), um experimento com a cultura da cana-de-açúcar. Foram utilizados 9 tratamentos com 4 repetições, implantados num delineamento em blocos ao acaso. Os tratamentos foram: tr1 - adubação mineral + calagem; tr2, tr3; tr4 e tr5 - doses de lodo de esgoto (respectivamente, 0; 33; 66 e 99 Mg ha-1, no primeiro ano, e 0; 37; 74 e 112 Mg ha-1, no segundo ano); tr6, tr7; tr8 e tr9 - doses de composto de lixo (respectivamente, 0; 20; 40 e 60 Mg ha-1, no primeiro ano, e 0; 24; 48 e 72 Mg ha-1, no segundo ano). Os resíduos foram aplicados manualmente na superfície do solo e incorporados com enxada rotativa, no primeiro ano em área total e no segundo apenas na entrelinha. Foram determinados, em cada parcela, os seguintes parâmetros do solo: composição granulométrica (amostras coletadas antes da implantação do experimento); o conteúdo de carbono orgânico (amostras coletadas em 15 datas durante os dois anos); conteúdo de argila dispersa em água, densidade e porosidade total (amostras coletadas ao final do primeiro e do segundo ano do ciclo da cultura); curva de retenção de água, condutividade hidráulica do solo saturado e condutividade hidráulica relativa (amostras coletadas ao final do primeiro ano do ciclo da cultura); e condutividade hidráulica do solo saturado e não saturado (determinada no campo ao final de dois anos do ciclo da cultura, utilizando o infiltrômetro de tensão). Os resultados obtidos mostraram que houve redução da densidade do solo e aumento da porosidade total com o aumento das doses dos resíduos, para a camada de 0 a 0,15 m de profundidade, no segundo ano de aplicação. Nas parcelas que receberam aplicações de ambos os resíduos, houve aumento da condutividade hidráulica do solo próximo à saturação e redução à medida que o solo se afasta da saturação, para a faixa de potencial mátrico estudada (0 a 1 kPa). O decaimento da condutividade hidráulica relativa, a partir da saturação, foi inicialmente mais acentuado nas parcelas que receberam aplicações de ambos os resíduos, quando comparadas às que não receberam resíduos. Verificou-se também, através de análises de regressão múltipla, que diferenças na retenção de água e no conteúdo de argila dispersa em água, que pela análise de variância convencional seriam atribuídas exclusivamente aos tratamentos, de fato eram parcial ou totalmente devidas a variações não casuais na composição granulométrica do solo. Pelos resultados pôde-se concluir que a aplicação de resíduos urbanos ao solo leva a modificações de propriedades como a densidade e porosidade total do solo, a condutividade hidráulica do solo saturado e a condutividade hidráulica do solo não saturado. Pôde-se concluir também que a casualização dos tratamentos na área experimental não garante a ausência de covariação entre os tratamentos e outras variáveis independentes, as quais podem interferir nas propriedades de interesse (variáveis dependentes) e, conseqüentemente, na eficiência da análise de variância feita de maneira convencional, sendo recomendado a realização de um "ensaio em branco" para verificar a eficiência desta casualização. / An experiment was carried out during two years on a Red Yellow Latosol cropped with sugar-cane, located in the country of Piracicaba-SP (22o41’00" S; 47o39’00" W; 554 m high). Nine treatments with 4 replications were used in a random-block experimental design. The treatments were: tr1 – mineral fertilization + CaCO3; tr2, tr3; tr4 and tr5 - levels of sewage sludge (respectively, 0; 33; 66 and 99 Mg ha-1, in the first year, and 0; 37; 74 and 112 Mg ha-1, in the second year); tr6, tr7; tr8 and tr9 - levels of composed of garbage (respectively, 0; 20; 40 and 60 Mg ha-1, in the first year, and 0; 24; 48 and 72 Mg ha-1, in the second year). The residues were manually applied on the soil surface and incorporated with a rotative plough. In the first year, the incorporation was done on the total area; in the second year only in inter-rows. The following soil parameters were determinated in each plot: particle size distribution (samples collected before the installation of the experiment); organic carbon content (15 samplings along the two years); natural clay content, soil bulk density and total soil porosity (sampling at the end of the first and second years of the growing cycle); water retention curves, saturated hydraulic conductivity and relative unsaturated hydraulic conductivity (samples collected at the end of the first year of the growing cycle); and saturated and unsaturated hydraulic conductivity (determined in situ at the end of the first and second years of the growing cycle, using tension infiltrometer). Results show a decrease the soil bulk density and increase of total porosity as the levels of residue application increased, for the 0 to 0.15 m soil layer, in the second year of application. On the plots that received applications of both residues, there was increase of the hydraulic conductivity near the soil saturation and decrease for the 0 to 1 kPa matric potential range. The decline of the relative hydraulic conductivity starting from the saturation, was initially more accentuated in the plots that received applications of both residues as compared with the ones that did not. It was also verified, through analyses of multiple regression, that differences in the water retention and in the natural clay content, that they would be attributed exclusively to the treatments by the conventional variance analysis, they were partially or totally owed to non casual variations in the particle size distribution of the soil. It could be concluded that the soil application of urban residues causes modifications of soil physical properties as saturated and unsaturated soil hydraulic conductivity. It could also be concluded that the randomization of the treatments in the experimental area does not guarantee the covariance absence between the treatments and other independent variables, which can interfere in the properties of interest (dependent variables) and, consequently, in the efficiency of the variance analysis done in a conventional way.

As crostas são o resultado da degradação da estrutura superficial dos solos, favorecem a erosão e a degradação ambiental dos solos. Este estudo avaloiu a dinâmica da formação de crostas superficiais e as consequencias sobre a porosidade, condutividade hidráulica (K), retenção de água, densidade (Ds) e a rugosidade de um Argissolo Vermelho amarelo conduzido com diferentes sistemas de preparo do solo e aplicação de lâminas de chuva simulada. Avaliou-se também, através de um experimento em laboratório, os processos envolvidos na quebra dos agregados, sob chuvas simuladas. O experimento foi conduzido, nos anos de 2009 e 2010. Em parcelas de 15 x 30 m foram conduzidos os diferentes preparos do solo: preparo convencional (PC), preparo reduzido (PR) e sem preparo (SP). Dentro das parcelas instalou-se micro-parcelas de 1m x 1m, onde foram aplicadas diferentes lâminas de chuva simulada (0, 27, 54 e 80 mm) com intensidade de 80 mm h-1. Foram realizadas coletas de dados de rugosidade, medidas de K, coleta de amostras indeformadas de solo para análise da porosidade e confecção de lâminas delgadas, e também anéis cilíndricos para curva de retenção de água (CRA) e Ds do solo. No experimento de laboratório, utilizou-se dois solos (siltoso e argiloso) e duas classe de agregados (1-3 e 3-5 mm). Os agregados foram submetidos a diferentes chuvas simuladas (28mmh-1 + EC forte; 28mmh-1 + EC fraca; 90mmh-1 + EC forte; 90mmh-1 + EC fraca) e após avaliou-se o diâmetro médio ponderado dos agregados (DMP). A dinâmica da formação de crostas ocorreu de maneira diferenciada em ambos os sistemas de preparo. Nos sistemas de PC e PR a maior redução da porosidade, pelo efeito da chuva aplicada, ocorreu na camada da crosta e no sistema SP na camada da subcrosta. A camada da crosta foi responsável pela redução da porosidade e K, e aumento da Ds nos sistemas PC e PR. As maiores umidades volumétricas observadas nas CRA ocorreram no sistema de PR e as menores no PC e não demonstraram evolução entre as chuvas aplicadas. A rugosidade superficial do solo variou em função dos sistemas de preparo realizados. Os sistemas conservacionistas (PR e SP) apresentaram maior rugosidade no primeiro ano, no segundo ano a maior rugosidade foi observada no sistema SP. O PC demonstrou nos dois anos estudados a mesma tendência, em função das chuvas aplicadas, inicialmente ocorreu um aumento na rugosidade até uma chuva máxima diminuindo em seguida. No experimento em laboratório, as maiores reduções no DMP ocorreram até a lâmina de 3 e 2 mm para o solo argiloso e siltoso, respectivamente. Nas quantidades iniciais de chuva (lâminas iniciais) a intensidade foi determinante na redução do DMP, com o aumento da quantidade de chuva a energia cinética (EC) passou a influenciar a redução do DMP. A intensidade de 28 mm h-1 promoveu as maiores reduções do DMP possivelmente pelo maior tempo de exposição dos agregados ao molhamento. / The crusts are the result of degradation of the surface structure of the soil, favoring erosion and environmental degradation of soils. This study evaluated the dynamics of the develop surface crusts and its consequences on the porosity, hydraulic conductivity (K), water retention, bulk density (Ds) and the roughness of a Typic Hapludult conducted with different systems of tillage and application of sheets simulated rainfall. Was also evaluated through the an laboratory experiment, the processes involved in the breakdown of aggregates under simulated rainfall. The experiment was conducted in the years 2009 and 2010. In plots of 15 x 30 m were installed the soil tillage: conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). Inside of the plots was installed micro-plots of 1m x 1m, which were applied different sheets of simulated rainfall (0, 27, 54 and 80 mm) with intensity of 80 mm h-1. Roughness data, K measurements, sampling of undisturbed soil samples for porosity analysis and preparation of thin sections, and also cylindrical rings for water retention curve (SWRC) and Ds, were collected. In the laboratory experiment two soils (Silt Loam and Clay Loam) and two aggregate classes (1-3 and 3-5 mm) were used. The aggregates were submitted to different simulated rainfall (28mmh-1 + KE strong; 28mmh-1 + KE weak; 90mmh-1 + KE strong; 90mmh-1 + KE weak) and after the mean weight diameter (MWD) was evaluated. The dynamics of crust formation occurred differently in both tillage systems. In the CT and RT systems the major reduction of the porosity, by effect of the applied rainfall, occurred in the crust layer and in the NT system occurred in the subcrosta layer. Crust formation was responsible for reducing the porosity and K, and increasing Ds, in RT and CT systems. The higher volumetric moisture contents observed in CRA occurred in the PR system and the lowest in CT. The CRA did not show changes between the applied rainfall. The surface roughness of the soil varied in relation to the tillage systems. RT and NT systems showed a higher roughness in the first year during the second year a higher roughness was observed in the NT system. The CT in the two years studied showed the same trend of evolution according to of applied rainfall, initially there was an increase in roughness up to a maximum rain and then decrease. In the laboratory experiment, the largest DMP reductions occurred in the 3 and 2 mm rainfall for the Silt Loam and Clay Loam soils, respectively. In the initial amounts of rainfall, the intensity was determinant in the MWD reduction. With the increase in the amount of rainfall, the kinetic energy influences the MWD reduction. The intensity of 28 mm h-1 produced the greatest reductions in DMP, possibly due to the longer exposure of the aggregates to wetting.

Plugged and abandoned well pads throughout the Uintah Basin face reclamation challenges due to factors including a harsh climate, invasive species, and high salt loads. Finding ways to alleviate soil sodicity could improve soil reclamation success. Gypsum, sulfur, activated carbon, and Biochar are being applied to improve soil parameters negatively impacted by sodicity, but the direct impact of these amendments on Uintah Basin soils is still largely unknown. The aim of this study was two-fold. (1) Evaluate the effectiveness of gypsum, sulfuric acid, Biochar, activated carbon, and combinations of these amendments in reducing the impact of soil sodicity of the Desilt and Conglomerate soils by measuring amendment impact on percent dispersion, saturated hydraulic conductivity, crust bulk density, infiltration, and crust formation. (2) Compare a crust bulk density method using ImageJ to the clod wax density method and a modified linear extensibility percent equation to the linear extensibility percent equation to assess whether the novel methods can be used to accurately measure and calculate soil crust bulk density and shrink swell potential while reducing human error and analysis time.

This study investigated the transport coefficients involved in mass and heat transfer during the drying of a porous solid partially saturated with multicomponent mixtures.  It included the coefficients governing liquid transport through the solid, the matrix of multicomponent diffusion coefficients in the liquid phase, and the effective thermal conductivity.  As it is not possible to determine these coefficients by theoretical considerations alone and considerable experimental work is required to determine them in a broad range of process conditions, the principle of this study has been the use of mathematical models complemented with some empirical parameters.  These empirical parameters were determined by comparison between measurements in specially designed experiments and the results of mathematical models that describe the process.  In addition, the application of the multicomponent diffusion coefficients is described in two cases where liquid diffusion is important: convective evaporation of a multicomponent stationary liquid film and a falling film. To study liquid transport through the solid, isothermal drying experiments were performed to determine the transient composition profiles and total liquid content of sand samples wetted with ternary liquid mixtures with different initial compositions and temperatures.  A mathematical model including mass transfer by capillary movement of the liquid and interactive diffusion in both the gas and liquid phases was developed.  To simulate the capillary movement of liquid mixtures, parameters experimentally determined for single liquids were weighed according to liquid composition. A fairly good agreement between theoretical and experimental liquid composition profiles was obtained considering that axial dispersion was included in the model. To study the matrix of multicomponent diffusion coefficients in the liquid phase, the redistribution of liquid composition in a partially filled tube exposed to a longitudinal temperature gradient was analysed.  Experimental work was carried out using two main ternary mixtures with different initial compositions and temperature gradients.  Experimental data were compared with the results of a theoretical model that describes the steady-state liquid composition distribution in a partially filled non-isothermal tube to find the empirical exponent that modifies the matrix of thermodynamic factors.  Correlations for the exponents as a function of temperature were determined for each particular multicomponent mixture. The effective thermal conductivity of a porous solid containing multicomponent liquid mixtures was studied by measuring the liquid composition, liquid content and temperature distributions in a cylindrical sample dried by convection from the open upper side and heated by contact with a hot source at the bottom side.  Simulations performed at a quasi steady state were compared with experiments to estimate the adjusting geometric parameter of Krischer’s model for effective thermal conductivity, which includes the contribution of the evaporation-diffusion-condensation mechanism. The results revealed that a resistance corresponding to a parallel arrangement between the phases seems to dominate in this case. In the study of the convective drying of a multicomponent stationary liquid film, the equations describing interactive mass transfer were decoupled by a similarity transformation and solved simultaneously with a conduction equation by the method of variable separation.  Variations of physical properties along the process trajectory were taken into account by a stepwise application of the solution in time intervals with averaged coefficients from previous time steps.  Despite simplifications, the analytical solution gives a good insight into the selectivity of the drying process and is computationally fast.  On the other hand, numerical simulations of the convective evaporation of the multicomponent falling liquid film into an inert gas with a co-current flow arrangement of the phases almost always revealed a transition from liquid-phase-controlled conditions to a process in which neither the gas nor the liquid completely controls the evaporation. The results obtained in this work would be useful in implementing models to improve the design, process exploration and optimisation of dryers by incorporating the solid-side effects to describe the drying of liquid mixtures along the whole process. / QC 20110124

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / Measurements of penetrability and hydraulic conductivity in calcareous soils treated with a dilute sulfuric acid solution showed a severe decrease in conductivity with increasing concentrations over 1000 ppm. A slight decrease in penetrability was observed. Carbon dioxide evolution appeared to be responsible for flow reduction and temporary cessation at 10,000 ppm and 20,000 ppm. In sodic soils penetrability and conductivity increased markedly with sulfuric acid concentrations between 1,000 and 10,000 ppm. For a neutral soil, penetrability decreased with increasing sulfuric acid concentrations, and the stable conductivity for 500 to 5,000 ppm was higher than for water alone. The findings suggest that disposal of sulfuric acid concentrations greater than 1,000 ppm will result in plugging by carbon dioxide. In sodic soils the possibility exists of using sulfuric acid solutions for reclaiming salt and sodium-affected soils.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / This study, conducted to determine the interrelationships among nitrogen transformations, infiltration rates, and development of the black layer found in the Santa Cruz River downstream of the Tucson (Arizona) sewage treatment plant, tested these interrelationships by percolating sewage effluent through clear acrylic columns uniformly packed with river sand for the first run, with gravel for the second run. Sewage effluent was continuously applied to three of the columns for 28 and 64 days during the first and second runs respectively. The remaining column was continuously flooded with tap water to serve as a control. Infiltration rates decreased rapidly upon application of the sewage, and within a few days a black layer developed, its thickness inversely related to the infiltration rate but not a cause of reduced flow, which is attributed, rather, to clogging of the surface by suspended solids. There was an average reduction in total nitrogen of 62.9% for the first run, and 15.9% for the second. The mechanisms of removal for run 1 were predominately absorption and denitrification, whereas the predominate removal mechanism in run 2 was filtering of organic nitrogen with adsorption and denitrification also playing an important role.

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