Do ponto de vista agronômico, a irrigação com efluente tem a grande vantagem de permitir a economia de água e adubos, uma vez que o efluente é naturalmente rico em nutrientes e matéria orgânica; no entanto, é também neste ponto que surgem as preocupações relacionadas ao ambiente. Se mal planejada esta aplicação, o excesso de nutrientes e matéria orgânica pode causar poluição e provocar alterações nas propriedades do solo, tanto químicas quanto físicas e hídricas. Tendo em vista a problemática acima exposta, o presente trabalho teve como objetivo estudar o efeito da irrigação com efluentes de esgoto tratado nas propriedades físicas e hídricas de um latossolo. A área experimental situa-se no município de Lins-SP e é composta de três parcelas: parcela Água (A), parcela Efluente (E) e parcela Testemunha (T), numa vertente imediatamente ao lado das lagoas. Todo o estudo foi realizado em 8 profundidades, até 1,875m. Determinou-se, em campo, através do método do perfil instantâneo, a condutividade hidráulica do solo em meio não saturado, K(&#952;); da mesma forma, determinou-se em laboratório através do método da carga decrescente, a condutividade hidráulica do solo saturado, Ksat. Avaliou-se também K(&#952;) em laboratório pelo sistema Wind (baseado na evaporação), comparando-o ao método do perfil instantâneo (baseado na drenagem). Analisou-se a porosidade do solo, através da distribuição do diâmetro dos poros obtida a partir das curvas de retenção de água. Os resultados mostraram que houve alterações da condutividade hidráulica do solo em ambas as parcelas irrigadas, com água e com efluente, em relação à parcela tomada como referência. Isto demonstra que, não só o efluente, mas também a irrigação convencional deve ser planejada com precauções na região em estudo, uma vez que a própria água de abastecimento utilizada é rica em sódio. As parcelas irrigadas apresentaram diminuição significativa de K(&#952;) em relação à parcela Testemunha nas umidades elevadas; por outro lado, o K(&#952;) aumentou nas parcelas irrigadas nas umidades baixas, o que sugere uma mudança na estrutura e na porosidade do solo. Em relação à Ksat, identificou-se um decréscimo nas parcelas irrigadas em relação à Testemunha ao longo de todo o perfil de solo. O sistema de laboratório Wind, mostrou-se mais adaptado a solos irrigados com águas sódicas do que o método do perfil instantâneo. A irrigação com efluente e com água (águas sódicas) levou à diminuição da microporosidade, isto é, a classe de poros de diâmetro entre 0,2 µm e 50 µm. Por outro lado o aumento significativo da criptoporosidade (<0,2 µm) foi identificado em todo o perfil de solo estudado. Houve correlações significativas entre os volumes de microporos e criptoporos, a porcentagem de argila dispersa em água e o Na+, o que resultou da ocorrência dos processos de dispersão e expansão dos agregados. / From the agronomic point of view, irrigation using treated sewage effluent has a great advantage in saving water and fertilizers, once effluent is naturally rich in nutrients and organic matter. However, some concerns related to the environment are raised regarding this aspect. The excess of nutrients and organic matter can cause pollution and provoke changes in the soil chemical, physical and hydraulic properties, in case this application is not well planned. The present work aimed to study the effect of irrigation using sewage treated effluent on the physical and hydraulic properties of an Oxisol. The experimental area is located in Lins-SP, and it is composed of three plots: Water plot, Effluent plot and Control plot located on a slope beside the ponds. All the study was carried out in 8 depths up to 1,875 m. The unsaturated soil hydraulic conductivity K(&#952;) was determined under field conditions using the instantaneous profile method. Similarly, saturated soil hydraulic conductivity, Ksat, was determined by using the falling head method. K(&#952;) was also evaluated, under laboratory conditions, by using the Wind system (based on evaporation), which was compared afterwards to the instantaneous profile method (based on drainage). The soil porosity was analyzed by means of the pores diameter distribution obtained from the water retention curve. The results showed that there were changes in the soil hydraulic conductivity in both plots irrigated with water and effluent, in relation to the reference one. This fact demonstrates that not only the irrigation with effluent, but also the conventional one must be managed with precautions in the studied area, once the water supplied to the city is rich in sodium. The irrigated plots presented a significant decrease in K(&#952;) in relation to the Control plot with higher water contents. On the other hand, K(&#952;) increased in the irrigated plots with lower water content, suggesting a change in the soil porosity. In relation to Ksat, a decrease in the irrigated plots in relation to the Control was identified along the whole soil profile. The Wind system showed to be more adapted to soils irrigated with sodium-rich water when compared to the instantaneous profile method. The irrigation with effluent and with water (sodium-rich waters) induced a decrease in the microporosity, that is, the pores class with diameter comprising between 0,2 µm and 50 µm. On the other hand, a significant increase in criptoporosity (<0,2 µm) was identified in the whole soil profile. Significant correlations among micropores and criptopores volumes, water clay dispersion, and Na+, which resulted from the aggregates dispersion and expansion processes.

Os movimentos de massa fazem parte da dinâmica da paisagem e se destacam como um dos principais processos geomorfológicos responsáveis pela evolução do relevo. Estes são condicionados por uma relação complexa de fatores naturais: geomorfológicos, geológicos e geotécnicos e hidrológicos. Tais tipos de movimentos de massa ficaram registrados em 17 e 18 de março de 1967 nas encostas da escarpa da Serra do Mar no município de Caraguatatuba, quando ocorreram de modo generalizado, causando um grande impacto ambiental, culminando em 120 mortes e 400 casas destruídas, mais concentrados em uma área de aproximadamente 180km2 em torno do município. Sendo assim, o objetivo deste trabalho é investigar algumas propriedades físicas do solo a fim de analisar a influência destas na distribuição e na deflagração dos escorregamentos translacionais rasos. As amostras de solo foram coletadas em três pontos, em diferentes profundidades (lateral, superior e interior) de três cicatrizes de escorregamentos rasos de 1967. As seguintes propriedades foram analisadas: distribuição granulométrica, limites de Atterberg, porosidade, densidade, curvas de retenção de água e resistência ao cisalhamento. As amostras apresentaram valores altos para as frações de areia, cerca de 80%, com uma composição granulométrica variável, destacando a existência de areias siltosas e pouco argilosas e siltes pouco argilosos, com os horizontes de solos mais profundos formados predominantemente por materiais siltosos e/ou arenosos, enquanto os horizontes superficiais apresentaram-se mais argilosos. Ainda que com baixos índices de atividade e por muitas vezes inatividades, não apresentaram significativa variabilidade quanto aos índices físicos onde os corpos de prova não atingiram a saturação total, alcançando uma média percentual de 70% de umidade e valores para densidade e índices de vazios muito próximos, de 2,55 g/cm3 e 1,151 g/cm3, respectivamente quanto aos parâmetros de resistência. Os ângulos de atrito foram menores para os horizontes superficiais (29,1º e 25,8º) em detrimento das camadas subjacentes, 1,75m e 2,00m, (31,9º e 36,8º). É importante ressaltar que boa parte dos estudos já desenvolvidos sobre a temática Serra do Mar Paulista focam o mapeamento destes processos na paisagem e o papel dos parâmetros topográficos, sobretudo da declividade, na distribuição dos mesmos. Entretanto, são escassas as informações sobre a tipologia e as propriedades dos solos, em escala de detalhe que possam efetivamente influenciar a estabilidade das encostas da Serra do Mar. Espera-se, portanto, que este estudo possa subsidiar em melhor entendimento dos mecanismos de ruptura dos escorregamentos rasos neste compartimento geomorfológico. / Mass movements are part of the landscape dynamics and stand out as major geomorphological processes responsible for the evolution of relief. These are determined by a complex of natural factors: geomorphological, geological and geotechnical and hydrological. These types of mass movements were recorded on 17 and 18 March 1967 on the slopes of the escarpment of the Serra do Mar in the city of Caraguatatuba, when there were so widespread, causing a major environmental impact, resulting in 120 deaths and 400 homes destroyed more concentrated in an area of approximately 180km2 around the county. Therefore, the objective of this work is to investigate some physical properties of the soil in order to analyze their influence on the distribution and outbreak of shallow translational landsliding. Soil samples were collected at three points at different depths (side, top and interior) of three shallow landslide scars from 1967. The following properties were analyzed: size distribution, Atterberg limits, porosity, density, water retention curves and shear strength. The samples had high values for the sand fractions, about 80%, with a variable grain size composition, highlighting the existence of silty sands and silts and clay little bit clay, with deeper soil horizons formed predominantly silty materials and / or sandy, while the surface horizons were more clay. Even with low levels of activity and often outages, showed no significant variation between the physical indexes where the samples have not reached full saturation, reaching an average percentage of 70% moisture content and density values for indices and very empty next, at 2.55 g/cm3 and 1.151 g/cm3, respectively for the parameters of resistance. The friction angles were smaller in surface horizons (29.1 º and 25.8 º) over the underlying layers, 1.75 m and 2.00 m (31.9 º and 36.8 º). Importantly, many of the studies already undertaken on the subject Serra do Mar Paulista focus on the mapping of these processes in the landscape and the role of topographic parameters, especially the slope in their distribution. However, there is little information about the types and properties of soils in detail scale that can effectively influence the stability of the slopes of the Serra do Mar. It is hoped, therefore, that this study may support better understanding of failure mechanisms of shallow landslides in geomorphological compartment.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The sustainability of vegetable oils production is in the dependence of the agricultural practices, being the erosion the most preoccupying form of soil degradation. In this way, was carried out a study in the UFSM campus, city of Santa Maria, between October of 2007 and October of 2009, with the objective to evaluate the soil and water losses by water erosion in systems of rotation of oleaginous crops and covering plants. The region climate is "Cfa" type, with 1686 mm annual medium precipitation. The soil with steepness of 6.5% is classified as Argissolo Vermelho distrófico arênico. The experimental unit is constituted of plots with dimensions of 3 m of width and 15 m of length. The experimental design is entirely random, with two repetitions. The treatments consist of three rotations: R1 (soybean, black oat/vetch, castor bean/peanut and canola), R2 (castor bean/peanut, oilseed radish, sunflower and black oat/vetch) and R3 (sunflower, canola, soybean and oilseed radish). Was determined the dry mass yield of summer and winter crops, and the grains yield of the oleaginous summer crops. Was done the sampling and measurement of runoff of each rain, being the soil and water losses calculated using the software Excel. The results of soil losses were expressed in kg ha-1 and the water losses in percent in relation to the rain. The erosivity index (EI30, MJ mm ha-1 h-1) was determined with the software Chuveros, from which was obtained the accumulated erosivity for each period of the crops. Was also proceeded the physical characterization (Dp, Ds, Pt, macro and microporosity, DMG, DMP and distribution of the aggregates size in water), in the depths of 0-8 and 8-16 cm, and chemistry (organic matter, macro and micronutrients) in the depths of 0-5 and 5-20 cm. To the obtained values, the test of Tukey was applied for comparison of the treatments averages. It is observed that canola, when compared to others wintrer crops, showed a significant decrease in dry mass in 2008 winter (R3) and also in winter of 2009 (R1). It is verified that are greater the productivity of grains of the crops of R2 (summer 2007/06) and R1 (summer 2008/09), both constituted by the consortium among castor bean/peanut, elevating significantly the total of grains produced in this consortium, comparing to single crop of soybean and sunflower. It is verified in 2009, a tendency of decrease of Ds, DMP and larger aggregates, favoring the minor classes. The alterations in the chemical characteristics can be attributed to the application of lime and the modifications in the tenors of organic matter that happen in depth. The soil and water losses increase in the measure in that it decreases to dry mass added by the crops. Even if is considered R3, where it was obtained the largest soil losses (4641 kg ha-1) and water (23.33%), it is observed that the values obtained in this work are low. Soybean and sunflower grain yield is significantly smaller than the consortiated castor bean and peanut crops. / A sustentabilidade da produção de oleaginosas está na dependência das práticas agrícolas, sendo a erosão a mais preocupante forma de degradação do solo. Desta forma, desenvolveu-se um estudo no campus da UFSM, cidade de Santa Maria, entre outubro de 2007 e outubro de 2009, com o objetivo de avaliar as perdas de solo e água por erosão hídrica em sistemas de rotação de culturas oleaginosas e plantas de cobertura. O clima da região é do tipo Cfa , com precipitação média anual de 1686 mm. O solo com declividade de 6,5% é classificado como Argissolo Vermelho Distrófico arênico. A unidade experimental constitui-se de uma parcela com dimensões de 3 m de largura e 15 m de comprimento. O delineamento experimental é inteiramente casualizado, com duas repetições. Os tratamentos consistem de três rotações: R1 (soja, aveia preta + ervilhaca, mamona + amendoim e canola), R2 (mamona + amendoim, nabo, girassol e aveia preta + ervilhaca) e R3 (girassol, canola, soja e nabo). Determinouse o rendimento da massa seca das culturas de verão e inverno, e a produção de grãos das culturas oleaginosas de verão. Realizou-se a amostragem e medição da enxurrada de cada chuva, sendo as perdas de solo e água calculadas, utilizando-se o programa computacional Excel. Os resultados de perdas de solo foram expressos em kg ha-1 e as perdas de água em % em relação à chuva. O índice de erosividade (EI30, MJ mm ha-1 h-1), foi determinado pelo programa Chuveros, a partir do qual se obteve a erosividade acumulada para cada período das culturas. Procedeu-se também a caracterização física (Dp, Ds, Pt, macro e microporosidade, DMG, DMP e distribuição do tamanho dos agregados em água), nas profundidades de 0-8 e 8-16 cm, e química (MO, macro e micronutrientes) nas profundidades de 0-5 e 5-20 cm. Aos valores obtidos, foi aplicado o teste de Tukey para comparação das médias dos tratamentos. Observa-se que a canola, quando comparada às demais culturas de inverno, apresenta uma redução significativa da MS no inverno de 2008 (R3) e também no inverno de 2009 (R1). Verifica-se que são superiores à produtividade de grãos das culturas da R2 (verão 2007/06) e R1 (verão 2008/09), ambas constituídas pelo consórcio entre mamona + amendoim, elevando significativamente o total de grãos produzido neste consórcio. Verifica-se em 2009, uma tendência de diminuição da Ds, DMP e agregados de maior tamanho, favorecendo as classes de menor tamanho. As alterações nas características químicas podem ser atribuídas à aplicação de corretivos e as modificações nos teores de MO que ocorrem em profundidade. As perdas de solo e água aumentam na medida em que diminui a MS adicionada pelas culturas. Mesmo que se considere a R3, onde se obteve as maiores perdas de solo (4641 kg ha-1) e água (23,33%), observa-se que os valores obtidos neste trabalho são baixos. A produção de grãos da soja e do girassol é significativamente menor que o cultivo consorciado da mamona com o amendoim.

La complexité remarquable du sol et son importance pour un large panel de services écosystémiques présentent des défis majeurs pour évaluer les processus pédologiques. En dépit des progrès importants accomplis au cours des cinquante dernières années dans la caractérisation des propriétés hydriques, les méthodes analytiques demeurent coûteuses et chronophages. La spectroscopie proche infrarouge (SPIR) a été largement utilisée comme technique rapide, non destructive et peu coûteuse pour prédire différentes propriétés du sol y compris la teneur en eau. Toutefois, moins d’attention a été accordée à l’évaluation des propriétés hydriques et leurs variations en fonction des propriétés physiques du sol. L’objectif principal de ce travail est d’analyser la validité et la pertinence de la SPIR dans l’évaluation des propriétés hydriques et leur relation avec les caractéristiques du sol.Dans cette étude nous nous sommes focalisés sur la largeur à mi-hauteur de la bande d’absorption proche de 1920 nm pour identifier un nouvel indice spectral, noté SWSI pour caractériser l’état hydrique du sol. Nos résultats montrent une relation linéaire entre SWSI et la teneur en eau du sol (R2 >0.9). Ils ont monté aussi que SWSI est pertinent pour étudier les effets de la texture, de la teneur en carbone organique et des pratiques agricoles sur les propriétés de rétention en eau du sol. En outre, en utilisant les paramètres de cette relation linéaire, nous proposons une nouvelle approche pour caractériser les propriétés hydriques et la qualité physique des sols. En comparaison avec des méthodes clas / The remarkable complexity of soil and its importance for a wide range of ecosystem services present major challenges to the assessment of soil processes. Although major progress in characterizing water retention properties has occurred in the last fifty decades, analytical methods remain costly and time-consuming. Near infrared spectroscopy (NIRS) has been widely used as a rapid, non-destructive and cost-effective technique to predict different soil properties, including soil water content. However, less attention has been paid to assessing soil water retention properties and its variations depending on soil physical properties. The main objective of this work is to analyze the relevance and accuracy of NIRS for assessing soil water retention properties as they are related to soil characteristics.In this study, we focused on the full width at half maximum of the absorption band near 1920 nm to identify a new NIRS index (Soil water spectral index, SWSI) which can be used to characterize the soil water retention properties. Our results show a linear relation between SWSI and soil water content (R2 >0.9). They also shown that SWSI to be relevant to study the effects of texture, organic carbon content and agricultural practices on soil water retention properties. Furthermore, using the parameters (slope and intercept) of this linear relation, we propose a new approach to characterize water retention properties and physical quality of soils. Therefore, NIRS approach performs better or similar in assessing soil water retention properties and soil quality compared to conventiona

Thesis (M.Sc. Agriculture (Soil Science)) -- University of Limpopo, 2021 / Woody plant encroachment results in the degradation of grasslands. It is defined here as the increase in density, cover and biomass of woody plants into formerly open grasslands, reducing grassland productivity. Globally, many arid and semi-arid savanna grasslands are affected by this land cover transformation which changes the vegetation structure by altering the ratio of woody plants relative to grass species and influences soil hydrology. In the existing literature there is limited information on the effects of woody plant encroachment on soil physical and hydrological properties, especially in savanna grasslands. This study quantified and compared the soil physical and hydrological properties in the topsoil and subsoil of open and woody plant encroached grassland sites located on two contrasting soil forms, namely Bainsvlei and Rensburg. To achieve this objective, the two soils were sampled at various depth intervals from dug soil profiles at both sites at Towoomba Research Station in Bela Bela, Limpopo Province, South Africa. Soil physical properties including bulk density, porosity and aggregate stability as well as hydrological properties (water retention and hydraulic conductivity) were determined from collected samples. Compared to open grassland, soil bulk density was 11% and 10% greater in the topsoil and subsoil, while porosity was respectively 6% and 9% lower in the topsoil and subsoil of woody plant encroached grassland for Rensburg soils. In Bainsvlei soil, there was a minimal increase and decrease in the soil bulk density and porosity, respectively. Soil aggregate stability increased by 38% in the subsoil of woody plant encroached grasslands in Rensburg soil, due to increasing clay content with depth. In Bainsvlei soil, the soil aggregate stability was 9% and 13% lower in the topsoil and subsoil of the woody plant encroached grasslands compared to open grassland. Furthermore, the results revealed that in both soils, there was lower soil water retention and hydraulic conductivity in the topsoil and subsoil layers of woody plant encroached grassland than in open grasslands. There were no significant differences observed for soil hydraulic conductivity in the Bainsvlei and Rensburg topsoil. The subsoil hydraulic conductivity decreased by 24% in Bainsvlei and 44% in Rensburg soils in the woody plant encroached grassland. The soil water retention (SWR) decreased with an increase in woody plants. Specifically, there was 25% and 42% decrease in SWR with woody plant encroachment in the topsoil and subsoil of Bainsvlei soil, respectively. The same trend was observed in the Rensburg soils with 50% and 19% decrease in SWR in the topsoil and subsoil, respectively. Overall, the results revealed that soil type and depth influenced soil physical and hydrological properties in the studied woody plant encroached savanna grassland. As such, interventions aimed at controlling woody plant encroachment need to factor in soil type and depth in the development of management practices tailored to improve the soil hydrology of savanna grasslands

Orientador: Paulo Torres Fenner / Banca: Cláudio Angeli Sansígolo / Banca: Sérgio Hugo Benez / Banca: Jorge Roberto Malinovski / Banca: Fernando Seixas / Resumo: Foram avaliados os efeitos causados ao solo pelo tráfego de máquinas florestais de corte e baldeio de madeira, com ênfase à compactação, em floresta de Eucalyptus grandis Hill ex Maiden, de 91 meses de idade, através do comportamento de parâmetros físicos e mecânicos de um Latossolo Vermelho Amarelo, com 480 g.kg-1 de areia total e 430 g.kg-1 de argila. Os tratamentos avaliados foram o trânsito anterior ao experimento, a fase de corte e processamento de madeira, efetuada por colhedora (harvester) sobre esteiras e a fase de extração, por trator transportador autocarregável (forwarder) com rodado de pneus, considerando-se as condições de presença ou ausência de cobertura de galhada. Os parâmetros físicos empregados na avaliação foram: densidade do solo, porosidade total, macroporosidade, microporosidade, água disponível no solo, taxa de infiltração de água, temperatura do solo e estabilidade de agregados a seco. Os parâmetros mecânicos avaliados foram resistência do solo à penetração e ao cisalhamento, densidade máxima do solo, teor de água crítico para compactação e grau de compactação. Também foram avaliadas a área de contato rodado-solo e a pressão de rodados sobre o solo. Adotou-se o delineamento inteiramente casualizado, sendo os resultados obtidos submetidos à análise de variância pelo Statistical Analysis System (SAS), com aplicação do teste Tukey a 5% e 10% de significância. Comparativamente, a densidade do solo, a resistência mecânica ao cisalhamento e a pressão de rodados sobre o solo foram maiores após o tráfego do trator transportador em relação ao conferido pela colhedora de madeira. Os parâmetros porosidade total, macroporosidade, microporosidade, água disponível e estabilidade de agregados a seco foram maiores na fase de corte de madeira do que na fase de baldeio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A study of soil compaction was carried out on a Red-Yellow Latosol with 43% of clay and 48% of sand, according to some soil physical and mechanical parameters in a harvester of a 91-month-old Eucalyptus grandis Hill ex-Maiden forest. The aim was to evaluate the influence caused by the traffic of a 100 kWa-tracked harvester followed by a 190 kWa-wheeled-forwarder, over and without slash, in comparison to the soil conditions before the harvesting operations. The physical parameters used were soil dry bulk density, total porosity, air-filled porosity, micro porosity, soil water availability and infiltration rate, temperature and soil mean aggregate sizes. The mechanical parameters were soil penetrometer resistance, shear strength, Proctor test and machine ground pressure. A randomized-block trial with 15 replicates was used, applying Statistical Analysis System (SAS) and Tukey test at 5% and 10% significance levels. Results showed that wheeled-forwarder increased soil dry bulk density, soil shear strength and soil machine pressure in relation to the tracked-harvester. Thus, the parameters total porosity, air-filled porosity, micro porosity, soil water availability and soil mean aggregate sizes were higher on harvesting than on wood hauling. The wheeled-forwarder operating without slash produced a higher soil dry bulk density, temperature and soil compaction degree. Also, this work condition decreased total porosity and air-filled porosity in relation to the same operation accomplished over slash. Micro porosity, water availability, soil infiltration rate, soil penetrometer resistance and the maximum soil dry bulk density were not affected by both machines working on both slash conditions. All the soil mechanized operations evaluated were rated higher than 2 MPa on soil penetrometer resistance parameter, looked like a soil limit to allow the root growing... (Complete abstract, click eletronic address below) / Doutor

Orientador: Morel de Passos e Carvalho / Banca: Ednaldo Carvalho Guimarães / Banca: José Augusto de Lollo / Resumo: O conhecimento dos atributos do solo, principalmente aqueles relacionados com sua distribuição granulométrica, tem grande influência na produtividade vegetal. No ano agrícola de 2002/2003 foram analisados atributos da planta e do solo: produtividade de grãos do feijoeiro (PG), produtividade de palha (PP), teor de argila (ARG), de silte (SIL) e de areia (ARE) de um Latossolo Vermelho Distroférrico sob plantio direto, do Campus Experimental da Faculdade de Engenharia/UNESP (Ilha Solteira/SP - Brasil: latitude 20°18’S; longitude 52°39’W). O objetivo foi analisar a variabilidade dos atributos pesquisados, de forma a caracterizar suas dependências espaciais, e as correlações, linear e espacial, entre eles. Foi instalada uma malha experimental para a coleta dos dados estabelecida com espaçamento de 10 x 10 m, contendo 135 pontos amostrais distribuídos numa área de 8000 m2. A variabilidade dos dados foi baixa para a ARG, média para o SIL e ARE, e alta para a PP e PG. A maioria apresentou moderada dependência espacial, com alcances entre 19,8 m (SIL) e 103,1 m (ARE), e de 29,8 m para a PG. Foi observada uma evidente correlação espacial entre todos os que apresentaram, dois a dois, os maiores coeficientes de correlação. Entretanto, entre aqueles que apresentaram os menores, os dados sugeriram, em alguns casos, haver uma moderada correlação espacial. / Abstract: The knowledge of the soil attributes, mainly those related with its particle-size diameter, has great influence on the vegetal productivity. In the agricultural year of 2002/2003 attributes of the plant and soil had been analyzed: grain productivity of common bean (GP), straw productivity (SP), clay content (CL), silt (SI) and of sand (SA) of a Red Latosol under no-tillage, pertainning to Experimental Station of Faculdade de Engenharia/UNESP (Ilha Solteira/SP - Brazil: 20º18' Latitude S; 52º39' Longitude W). The objective was to analyze the variability of the researched attributes to characterize its spatial dependences. Also, to study the correlations, linear and spatial, between them. An experimental grid for the collection of the data was installed, established with distance of 10 x 10 m, contends 135 points shows in an area of 8000 m2. The data variability was low for the CL, medium for the SI and SA, and high for SP and GP. The majority then presented moderate spatial dependence, with ranges between 19.8 m (SI) and 103.1 m (SA), and of 29.8 m for the GP. An evident spatial correlation was observed between all the ones that had presented, two to two, the biggest correlation coefficients. However, between the ones minors, the data had suggested, in some cases, to have an moderate spatial correlation. / Mestre

<p> Measurements of soil atmosphere, soil physical parameters, coliform levels and ionic levels were made at 15 soil sites along Ancaster and Grindstone Creeks in winter, 1972-73 and July, 1973. Multivariate analysis of the data indicated large fluxes of septic effluent resulted in soil fabric alterations, anaerobosis, and elevated coliform, nitrate, chloride and sodium levels. According to ecological and health criteria, these hydromorphic soils have very serious limitations as processors and absorbers of septic effluent. </p> / Thesis / Master of Science (MSc)

The Southeastern Lower Coastal Plain wet pine flats include thousands of acres of jurisdictional wetlands that are economically, socially, and environmentally important. These highly productive forests have been intensively managed as pine plantations for the past few decades. More recently, harvesting and site preparation practices have become a concern among natural resource managers because intensive forestry practices may alter soil physical properties and site hydrology. These alterations could decrease seedling survival, growth, and future site productivity. However, the effects of soil disturbance on long-term site productivity and the effects of amelioration techniques on site hydrology are uncertain. The overall objectives of this study were (1) to characterize disturbed forest soil morphology and physical properties, (2) to assess their impact on the processes that control site hydrology and site productivity, (3) to determine effects of harvesting and site preparation on site hydrology, specifically on the overall hydrological balance and on spatial and temporal patterns of surface water storage. The study site is located in an intensively managed loblolly pine (Pinus taeda L.) plantation in the lower coastal plain of South Carolina. This study was established in winter 1991, and dry- and wet-weather harvesting treatments were installed in summer 1993 and winter 1994, respectively. Bedding and mole channel/bedding treatments were installed in both dry- and wet-harvested plots in fall 1995. Soil profiles were described for a recently disturbed, deeply-rutted area, and 2-year-old deeply-rutted and churned areas, bedded and undisturbed areas. Intact soil core samples and composite loose soil samples were collected from each morphological section for soil physical characterizations. Automated weather station and wells were used to collect continuous climatic and surface water level data since 1996. Surface water levels were monitored monthly on a 20 x 20 m grid of 1-m wells since 1992. Total groundwater heads were determined from differential piezometer measurements at high and low elevation places in each treatment plot. Soil profile descriptions and soil physical property measurements indicated that significant amounts of organic debris were incorporated into the surface horizons, and subsurface soil horizons showed significant soil structural changes and increased redoximorphic features caused by soil disturbance. The disturbed soil layers in recently created traffic ruts consisted of exposed and severely disturbed subsurface soils, but this layer was naturally ameliorated 2 years after the disturbance. Bedding site preparation had little amelioration effects on the physical properties of surface soil horizons because the surface horizons already had some incorporation of organic debris. Overall, the main consequence of bedding in a disturbed wet site was to increase the aerated soil volume. The bedding appeared to have little effect on disturbed subsurface horizons. Groundwater head in the study site was constantly higher than -25 cm during the study period, which caused groundwater inflow when the surface water level was low. Frequent fluctuation of the surface water level and constant water supply from the groundwater probably explain the high productivity of the study site. Results of the annual water balance showed that surface soil water storage changes were very small, and annual precipitation and potential evapotranspiration were approximately equal. Silvicultural practices and minor topography on the study site had significant effects on the water balance because they influenced surface water level. Surface water hydraulic gradient evaluation and multivariate cluster analysis indicated that micro-site hydrology and water flow patterns were significantly altered by wet-weather harvesting and bedding site preparation, but overall site hydrology was not altered. Evaluation of predicted surface water level indicated that micro-topography and precipitation patterns had significant influences on surface water levels during the site establishment period. These results revealed that the hydrologic components of wetland delineation are complex in the wet pine flatwoods. / Ph. D.

Reducing groundwater withdrawals from the Mississippi River Valley Alluvial Aquifer is imperative to sustain future irrigated cropping systems in the mid-southern USA. This research was conducted to determine the impacts of cover crops and irrigation sensor thresholds on corn (Zea mays L.) and soybean (Glycine max L.) production, water productivity, irrigation water use efficiency, and soil physical properties in the Mississippi Delta. The cover crop treatments included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa R.), wheat (Triticum aestivum L.)-radish (Raphanus sativus L.)-turnip (Brassica rapa L.) mix, and no cover crop. The irrigation thresholds included -40 kPa, -90 kPa, and no irrigation. In 2020, cover crops and irrigation thresholds showed minimal impacts on most of the measured parameters but showed improvements as the study progressed. After two years, it was determined that long-term evaluations are needed to make a recommendation to producers in the mid-southern USA.