Este trabalho apresenta a caracterização geoambiental de solos de uma área contaminada, localizada no município de Santo André, Estado de São Paulo, Brasil. O objetivo foi determinar parâmetros experimentais para permitir o estudo de alguns aspectos do transporte do pesticida organoclorado Hexaclorociclohexano (HCH). A área de estudo contém células com cerca de 30.000 toneladas de um material contendo HCH em elevadas concentrações. As investigações de campo demonstram que há concentrações de HCH na água subterrânea. Em 2011, foram coletadas amostras deformadas e indeformadas de solo em quatro diferentes pontos superficiais da área contaminada, e posteriormente uma amostra composta da camada de solo de alteração de rocha (SAR), a fim de responder a questionamentos quanto à mobilidade do contaminante na área. A caracterização geoambiental, baseada em ensaios laboratoriais, foi realizada por meio das seguintes análises: análise granulométrica, limites de Atterberg, densidade específica, porosidade, umidade do solo, curva de retenção de água no solo, condutividade hidráulica, ensaio de adsorção, pH, condutividade elétrica, capacidade de troca catiônica (CTC), teor de matéria orgânica e teor de voláteis. O solo superficial da área é heterogêneo e a capacidade de adsorção dos solos analisados foi menor do que o esperado. Esta caracterização subsidiou o estudo de fluxo e transporte do HCH, por meio de simulação numérica, utilizando o programa Hydrus 1D. As simulações tiveram dois objetivos diferentes: no primeiro foi avaliado os resultados da simulação em comparação à situação atual no campo; no segundo foi avaliada a sensibilidade do transporte em função da alteração dos parâmetros obtidos experimentalmente Ks; Kd; s e (Van Genuchten); e dos parâmetros obtidos na literatura. Os resultados permitiram concluir que o modelo Hydrus 1D consegue representar a contaminação do HCH no solo. O parâmetro de degradação na água foi essencial para chegar em ordens de grandeza de concentrações próximas das identificadas em campo. Os parâmetros de degradação, difusividade, dispersividade e condutividade hidráulica são os que mais afetam os resultados finais de concentração do HCH na água subterrânea e, portanto, merecem atenção maior durante as futuras investigações. / This paper presents the geoenvironmental characterization of soils from a contaminated site, located in Santo André, São Paulo State, Brazil. The objective was to determine experimental parameters to allow the study of some aspects of transport of the organochlorine pesticide hexachlorocyclohexane (HCH). The study site contains trenches with about 30,000 tons of a material containing high concentrations of HCH. The site investigations show that there are HCH concentrations in groundwater. In 2011, disturbed and undisturbed soil samples were collected at four different surface points of the contaminated site, and then a sample of soil from rock alteration layer (SAR) was also composed for characterization in order to answer questions concerning the mobility of contaminant in the site. The environmental characterization based on laboratory tests, was performed by the following analyzes: grain size distribution, Atterberg limits, specific gravity, porosity, moisture content, water retention curve, hydraulic conductivity, pH, electrical conductivity, cation exchange capacity (CEC), organic matter content and volatile content. The surface soil of the area is heterogeneous and the adsorption capacity of the soils analyzed were lower than expected. This characterization allowed the study of flow and transport of HCH through numerical simulation using the Hydrus 1D software. The simulations had two different goals, the first was evaluated the simulation results compared to the current situation in the field. In a second step the sensitivity of transport due to the change of the parameters obtained experimentally Ks; Kd; s and (Van Genuchten); and parameters obtained from the literature. The results showed that the Hydrus 1D model simulates HCH contamination in soil. Water degradation parameter was essential to get orders of magnitude similar to those identified in field concentrations. The degradation, diffusivity, hydraulic conductivity and dispersivity parameters are those that most affect the final results of concentration of HCH in groundwater and therefore deserve more attention in future investigations.

A adubação tem o intuito de fornecer nutrientes (solutos) às plantas em quantidades requeridas no momento adequado, visando obter produções agrícolas economicamente viáveis. Todavia, em alguns casos, o manejo da adubação não é feito de maneira correta, principalmente por se utilizar quantidades excessivas desses nutrientes. Juntando-se a esse fato, a água da irrigação e/ou da chuva, pode vir a ser um facilitador do escoamento superficial e da lixiviação através do perfil de solo, tornando-se, dessa forma, indisponível às plantas e, podem provocar a poluição de águas superficiais através da erosão hídrica e eutrofização, além da contaminação de águas subterrâneas e a acidificação de camadas do solo. Portanto, para evitar esses impactos ambientais, é necessário conhecer e entender a dinâmica de solutos no perfil de solo mediante a obtenção de informações que venham a caracterizar esses processos. Dentro dessas informações, tem-se a obtenção dos parâmetros de transporte de solutos. Tais parâmetros podem sofrer várias interferências do meio poroso, dentre elas a composição físico-química e mineralógica dos solos, a qual poderá determinar a capacidade de retenção ou dispersão desses íons. Dessa forma, o objetivo dessa pesquisa foi avaliar o efeito da composição físico-química e mineralógica de alguns tipos de solo sobre a dinâmica dos íons nitrato, fósforo e potássio, mediante a análise de seus parâmetros de transporte, obtidos pelo ajuste numérico das curvas de distribuição de efluentes (Breakthrough Curves, BTC) aplicando o código CFITIM dentro do software STANMOD (STudio of ANalytical MODels). Além disso, utilizando-se colunas com diferentes alturas (10 e 20 cm) e buscou-se recomendar qual altura de coluna possui acurácia sobre os parâmetros mediante simulações numéricas das BTC\'s pelo modelo HYDRUS-1D. A pesquisa foi conduzida junto ao Departamento de Engenharia de Biossistemas da Universidade de São Paulo (USP/ESALQ). Os tratamentos foram distribuídos em um esquema fatorial de 5 x 2, ou seja, cinco tipos de solo e duas alturas de colunas de solo para cada íon, individualmente. O delineamento experimental foi em blocos casualizados, com três blocos, totalizando 30 parcelas por soluto. Para a análise dos resultados, os parâmetros de transportes foram submetidos à análise de variância e a avaliação do desempenho do modelo pelos índices estatísticos: Raiz do Erro Quadrático Médio (RMSE), Erro Absoluto Médio (MAE) e o Coeficiente de Determinação (R2). Diante dos resultados obtidos, o solo PV foi diferente estatisticamente dos demais solos em todos os íons no coeficiente de dispersão. Diante das diferentes nas alturas das colunas, os solos PV, PVAe, NV e PVAd apresentaram diferenças significativas no fator de retardamento e os coeficientes de distribuição e dispersão nos íons nitrato e potássio. Sendo assim, recomendou-se a altura de 20 cm, pois os parâmetros determinados foram precisos em relação a 10 cm, pelo fato do modelo HYDRUS-1D ter alcançado um desempenho adequado nas simulações das BTC\'s nos solos arenosos e argilosos. / Fertilizer is applied to provide nutrients (solutes) for plants in required quantities, and at the right time, to facilitate economically viable agricultural production. However, in some cases excessive quantities of fertilizers are applied. Such overapplication can result in runoff and ions leaching through the soil profile, where they are unavailable to plants, and can cause surface water pollution by water erosion and eutrophication, besides of groundwater contamination and soil acidification. To avoid these environmental impacts, it is necessary to characterize the transport parameters that govern the dynamic of solutes in soil profile. These parameters are influenced by porous media properties, such as mineralogical composition of soils, that regulate the retention or dispersion of ions. The objective of this study was to evaluate the effect of physicochemical and mineralogical composition of soils on transport parameters of nitrate, phosphorus, and potassium, estimated by using the CFITIM code inside of STANMOD (STudio of ANalytical MODels) software to fit BTC\'s. Besides that, using of columns with different heights (10 and 20 cm) and recommended the columns height with accuracy under transport parameters by numerical simulations of the BTC\'s using the HYDRUS-1D model. The research was conducted in the Department of Biosystems Engineering, University of São Paulo (USP/ESALQ). The treatments were a 5 x 2 factorial with five soils and two column heights for each individual solute. The experimental design was random blocks, with three blocks, totaling 30 plots for each solute. For analysis of results, the transport parameters were submitted a variance analysis and the evaluation of model performance by statistical indexes: Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Determination Coefficient (R2). The dispersion coefficient for PV soil were significantly different from those for other soils, for all ions. In front of the different heights of the columns, PV, PVAe, NV and PVAd soils showed significant differences in retardation factor, and distribution and dispersion coefficients, for nitrate and potassium ions. The parameters obtained from 20 cm columns were accurate than those obtained from 10 cm height, based on adequate performance of HYDRUS-1D model in BTC\'s simulations of sandy and clay soils.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-15T12:09:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Tassia Melo_Final.pdf: 21742689 bytes, checksum: d3eb5a7ea85beafabdb3f870e3431701 (MD5) / Made available in DSpace on 2016-07-15T12:09:44Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Tassia Melo_Final.pdf: 21742689 bytes, checksum: d3eb5a7ea85beafabdb3f870e3431701 (MD5) Previous issue date: 2015-12-18 / FACEPE / Técnicas compensatórias são implantadas com a finalidade de resgatar os mecanismos naturais de escoamento, diminuir as vazões a jusante e maximizar o controle de escoamento na fonte. A fim de contribuir com os estudos sobre essas técnicas, este trabalho apresenta um estudo experimental de uma trincheira de infiltração instalada na cidade de Recife / PE nos primeiros meses de vida útil. Foram avaliadas as funções de armazenamento de água no interior do sistema e a função de infiltração, através de modelagens analítica e numérica sobre o processo de recessão. O modelo de Bouwer (1969) foi adotado para a modelagem analítica de dez curvas de recessão com dados reais. Os parâmetros de resistências hidráulicas da base e das paredes apresentaram valores elevados, representando a formação de uma camada de colmatação na interface trincheira de infiltração - solo natural. O Hydrus 2D foi utilizado para modelar numericamente doze curvas de recessões com dados artificiais, a fim de parametrizar o comportamento de trincheiras de infiltração quando implantadas em solos de diferentes classificações texturais. A modelagem mostrou melhor desempenho hidráulico da trincheira de infiltração instalada em solos de composição arenosa. Por fim, para as curvas de recessão artificiais, foi avaliada a relação entre os parâmetros obtidos analiticamente - resistências hidráulicas, e numericamente - curva de retenção e condutividade hidráulica, e os resultados mostraram que não é possível relacionar os parâmetros obtidos analiticamente com os parâmetros clássicos hidrodinâmicos obtidos numericamente. / Compensatory techniques are implemented for the purpose of recovering the natural mechanisms flow, decrease the downstream flow and maximize the flow control at the source. In order to contribute to the studies on these techniques, this paper presents an experimental study of an installed infiltration trench in Recife / PE in the first months of life. They evaluated the water storage functions within the system and infiltration function, by analytical and numerical modeling of the recession process. The model Bouwer (1969) was adopted for the analytical modeling ten recession curves with real data. The parameters of hydraulic resistances of the base and the walls showed high values, representing the formation of a fouling layer infiltration trench interface - natural soil. 2D Hydrus numerically modeling was used to twelve curves recessions with artificial data, in order to parameterize the behavior of infiltration trenches when implemented in different soil conditions ratings. The modeling showed better hydraulic performance of the installed infiltration trench in sandy soil composition. Finally, for the artificial recession curves, it evaluated the relationship between parameters obtained analytically - hydraulic resistances, and numerically - retention curve and hydraulic conductivity, and the results showed that it is not possible to relate the parameters obtained analytically with the classic parameters hydrodynamic obtained numerically.

Leaching of soil salinity in irrigated and non-irrigated agriculture is crucial to ensure sustainable food production. Soil salinity is considered a global problem, since more than 800 million hectares (6% of the world's total area) worldwide are salt-affected. Generally, the regions affected by soil salinity also face water scarcity problems. Consequently, in these regions, even saline waters are considered to be essential resources for agriculture. The use of inefficient irrigation practices in regions that experience water scarcity, especially those using saline water, aggravates soil salinity problems. Therefore, in the context of these constraints and challenges, increasing the efficiency of water use for irrigation and leaching is necessary. An increasing interest in using drip irrigation systems (DI) is noticed in the current research that deals with water scarcity due to the benefits of applying water precisely in time and space. However, the traditional leaching guidelines, based on steady-state conditions, are not appropriate for DI. Therefore, the use of DI for leaching practices is still under question. The objectives of this study are (i) to better understand and assess the leaching process for common DI, and (ii) to develop a simulation-based optimization approach considering site-specific conditions for optimal DI design for salinity management. Accordingly, a new two-stage framework for optimizing leaching practices has been developed focusing on DI. The transient-state-based numerical model HYDRUS-2D was used for simulating water movement and solute transport processes for both stages. In the first stage, a general assessment tool for leaching practices in the form of “irrigation atlas” was created using two-dimensional (2D) numerical experiments. The atlas displays and compares the reclamation leaching results of (i) surface drip irrigation (SI), (ii) subsurface irrigation drip irrigation (SDI), (iii) sprinkler irrigation (S), and (iv) flood irrigation. The results are introduced graphically, showing the final 2D salinity distribution in the soil profile, and numerically giving the water and salt mass balances. The SI and SDI results show the high potential of these systems for improving the efficiency of salinity leaching. However, because of the resultant localized leaching patterns, the performance of these systems depends on the location of the drip line relative to the targeted leaching area. In the second stage of the study a site-specific optimization framework for leaching design and management was developed through a combination of simulation and optimization. The objective was to achieve optimal leaching results with a given limited amount of water. The framework was applied in synthetic field conditions for reclamation leaching in two and silt). Moreover, the framework was based on running numerous simulations of possible DI setups (scenarios). The optimization approach made it possible to derive values for the optimal irrigation design parameters for salinity management under the given field conditions. The new optimization framework was implemented in a case study focusing on the impact of different DI designs on yield and the leaching of salts. The framework aims to make the most effective use of an existing DI system by optimizing the combination of irrigation frequency, duration, and discharge. The optimization framework was successfully employed: (i) to increase the relative yield of the considered crop, and (ii) to reduce the subsurface drainage towards the saline and shallow groundwater, which contributes to better control of the saline groundwater levels in the study area. The seasonal results confirmed the leaching pattern of a dripper presented in the irrigation atlas. The optimal seasonal solutions are presented as site and crop specific leaching and water productivity functions for a wide range of applied water and different irrigation water salinities. The developed optimization framework proved to be a suitable approach for assessing and improving leaching management of DI under salinity conditions and deriving optimal design parameter values. The suitability and flexibility of the framework were verified through implementation in a case study with new field conditions and objectives, and it was shown that the reliability of the proposed framework depends on the quality of the collected and measured data required for the model inputs.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Soils subjected to successive pig slurry (PS) amendments present zinc (Zn) and copper (Cu) increases, mostly on soil surface layer. The continuous application of PS causes accumulation of these heavy metals (HM) in soil, increasing risks for environmental contamination. Therefore, development of methods to estimate Zn and Cu accumulation in surface layer and their movement in soil is very important for the management planning of PS and of the agricultural soils amended with these residues. The main objective of this work was to model the vertical transport of Zn and Cu in profile of agricultural soils receiving successive application of PS at high, moderate and low doses, evaluating the effects of soil tillage and water absorption by roots on the movement of these HM. We also aimed to predict the long-term accumulation of HM in soil surface and their transport into groundwater, comparing estimated results with the threshold values established for agricultural soils and groundwater by the Conselho Nacional do Meio Ambiente (CONAMA). Two studies were performed on field experiments composed by different PS doses, the first located on an Alfisol in Santa Maria RS, and the second on an Oxisol in Campos Novos SC. Hydro-physical and chemical characteristics of these soils were measured and, accompanied by atmospheric and PS application data sets, were introduced into HYDRUS-1D for parameterization of the two-site model used. In the first study, simulations for next 100 years were performed under scenarios combining two PS doses and four time intervals between soil tillage of the arable layer. The solute transport model used on these simulations was already validated for this local soil in another study. In the second study, the validation of a solute transport model was carried out primarily, following the same approaches used for the Alfisol. Afterwards, root water uptake and root growth modules were introduced to the model. The future scenarios were simulated using applications of different PS doses during the next 50 years. The solute transport model previously validated for the Alfisol was also validated for the Oxisol, and the introduction of the root modules in HYDRUS-1D produced even better results. This increased the usefulness of the model for its use in simulations related to Zn and Cu transport on other contaminated soils. Future scenarios exhibit a great accumulation of these two HM in soil surface layer during the simulated times. Moreover, when soils are submitted to high PS annual doses, its Cu concentrations reached the maximum values established by CONAMA for agricultural soils in approximately 94 years on the Alfisol and in 29 years on the Oxisol. Reduction in PS doses and sporadic soil tillage are strategies that slow the increase of these HM concentrations in soil surface layer, decreasing so the environmental risks and making PS additions on agricultural soils viable for longer time. / Solos submetidos a sucessivas aplicações de dejeto líquido de suínos (DLS) apresentam incrementos nos seus teores de zinco (Zn) e cobre (Cu), principalmente na camada superficial. A continuidade dessa prática faz com que esses metais pesados (MP) se acumulem no solo, aumentando o potencial de contaminação do ambiente. Dessa forma, o desenvolvimento de métodos que estimem o acúmulo superficial e o movimento de Zn e Cu no solo é de extrema importância no planejamento do manejo dos DLS e dos solos agrícolas que recebem esses resíduos. O trabalho objetivou modelar o transporte vertical de Zn e Cu no perfil de solos agrícolas contaminados por aplicações sucessivas de altas, moderadas e baixas doses de DLS, avaliando o efeito do revolvimento do solo e da absorção de água pelas raízes no movimento desses MP, prevendo, no longo prazo, seus acúmulos na camada superficial do solo e suas transferências rumo ao lençol freático, confrontando os resultados estimados com os respectivos limites de concentração para solos agrícolas e águas subterrâneas estabelecidos pelo Conselho Nacional do Meio Ambiente (CONAMA). Foram realizados dois estudos em experimentos de campo com diferentes doses de DLS, o primeiro localizado sobre um Argissolo, em Santa Maria RS, e o segundo sobre um Latossolo, em Campos Novos SC. Diversas características físico-hídricas e químicas foram determinadas nesses solos para, juntamente com os dados atmosféricos e do histórico de aplicação de DLS nessas áreas, serem introduzidos no HYDRUS-1D para parametrização do modelo químico de dois sítios utilizado. No primeiro estudo foram realizadas simulações para os próximos 100 anos, considerando cenários combinando duas doses de DLS e quatro intervalos de tempo entre revolvimentos periódicos da camada arável do solo. O modelo de transporte de solutos utilizado nessas simulações já havia sido validado para o solo deste local em outro trabalho. No segundo estudo foi feita a validação de um modelo de transporte de solutos, seguindo as mesmas premissas do modelo utilizado no Argissolo. Posteriormente, módulos de absorção de água e crescimento de raízes foram incorporados ao modelo. Realizaram-se então simulações futuras de cenários considerando aplicações de diferentes doses de DLS durante os próximos 50 anos. O modelo de transporte de solutos validado previamente no Argissolo foi validado também no Latossolo, apresentando resultados ainda melhores quando os módulos de raízes foram introduzidos no HYDRUS-1D. Isso aumenta a abrangência desse modelo para simular o transporte de Zn e Cu em outros solos contaminados. Os cenários futuros mostram que ocorre grande acúmulo desses MP na camada superficial do solo durante os períodos simulados. Além disso, quando os solos são submetidos a altas doses anuais de DLS, as suas concentrações de Cu atingem os valores máximos estipulados pelo CONAMA, para solos agrícolas, em aproximadamente 94 anos no Argissolo e 29 anos no Latossolo. Reduzir as doses de DLS e revolver o solo esporadicamente são alternativas que retardam o aumento da concentração desses MP na camada superficial do solo, diminuindo o potencial de impacto ao ambiente e tornando a adição de DLS em áreas agrícolas viável por mais tempo.

Dans un contexte de changement climatique dont les projections régionales sont incertaines, de forte variabilité inter-annuelle du cycle hydrologique, de forte croissance démographique et de changement d'occupation des sols, les questions relatives au cycle hydrologique et à la ressource en eau actuels et à venir sont cruciales. Dans un tel contexte, ce travail de thèse approfondit la connaissance du fonctionnement hydrologique du bassin versant de l'Ouémé supérieur (situé en climat soudanien au Bénin), en considérant l'ensemble des termes et des processus du cycle hydrologique.Dans un premier temps, le fonctionnement hydrologique de l'Ouémé supérieur est analysé à l'échelle d'un versant grâce au modèle Hydrus 2D. Cette analyse de processus s'appuie sur un ensemble complet de mesures (précipitations, évapotranspiration, humidité du sol, niveau piézométrique, débit en rivière) obtenues dans le cadre de l'observatoire hydrométéorologique AMMA-CATCH. Les simulations montrent que la forêt ripisylve vidange la nappe profonde et la déconnecte ainsi du réseau hydrographique. L'apport d'eau de la nappe profonde permet une transpiration de la forêt ripisylve toute l'année, y compris en saison sèche. Les écoulements en rivière ne sont pas produits uniquement par exfiltration d'écoulements latéraux de subsurface non saturés, les bas-fonds jouent probablement un rôle.À méso-échelle, nous cherchons à quantifier l'impact de la variabilité spatiale de la conductivité hydraulique à saturation sur le bilan hydrologique et l'évapotranspiration. Le modèle numérique utilisé est nTopAMMA, formalisme dérivé de TopMODEL. À partir de mesures de terrain, nous avons mis en évidence que la variabilité spatiale de la conductivité hydraulique à saturation est corrélée à l'occupation du sol du bassin d'étude. La prise en compte de cette variabilité spatiale dans le modèle nTopAMMA montre que l'état hydrique et l'évapotranspiration simulés localement par le modèle dépendent aux trois-quarts de la topographie et pour un quart de la conductivité hydraulique à saturation.Adoptant une approche ascendante, nous confrontons la représentation élaborée à l'échelle du versant à la modélisation hydrologique à méso-échelle. Nous analysons les processus et flux verticaux du modèle nTopAMMA. L'amélioration de la modélisation du cycle hydrologique de l'Ouémé supérieur par le modèle nTopAMMA nécessite (i) la prise en compte des hétérogénéités du bassin versant, (ii) la modification du formalisme de l'évapotranspiration, (iii) la diversification des sources de prélèvements évapotranspiratoires et (iv) l'intégration de la nappe d'altérites. / Understanding how the hydrological cycle and water resources availability evolve in the current context of global change (which encompass climate, environmental and population changes) is a critical issue, particularly in West Africa, where at regional scale, strong interannual and seasonal variabilities overlap with highly uncertain climate predictions. Within this framework, this work aims at improving our knowledge of the behavior of the Upper Oueme catchment in Benin (Sudanian climate), with an analysis of all the hydrological processes and terms of the terrestrial hydrological cycle.First, the hillslope scale is considered by using the Hydrus 2D software and field observations from the hydrometeorological observing system AMMA-CATCH: rainfall, actual evapotranspiration, soil moisture, groundwater level and river runoff. The principal result of this analysis is that the riparian forest transpiration depletes the deep groundwater and disconnects it from the river network. Water supply by the deep groundwater enables the riparian forest transpiration all year long and particularly during the dry season. Seepage of unsaturated subsurface lateral flows contributes to river runoff, but the "bas-fonds" seem to be other important contributors.Then, at mesoscale, we quantify the impact of the spatial variability of hydraulic conductivity on the simulated water balance, with focus on the evapotranspiration term. The numerical model nTopAMMA, especially derived from the TopMODEL hydrological model for the Upper Oueme catchment, is used here. Measurements from a specific field mission evidence the correlation between the hydraulic conductivity spatial variability and the land use one. By taking into account this variability, the simulation results show that evapotranspiration and water storage simulated on the Upper Oueme catchment at local (pixel) scale depend essentially on the topography (75 %) and to a lesser extent on the hydraulic conductivity (25 %).Finally, a bottom-up approach is adopted to analyse the hydrological modelling results at mesoscale, taking advantage of the modelling results at the hillslope scale. Vertical processes and fluxes simulated by nTopAMMA are analyzed. It is shown that an improvement of the Upper Oueme hydrological cycle modelling, with nTopAMMA, requires: (i) the consideration of the catchment heterogeneities, (ii) the modification of the evapotranspiration module, (iii) the diversification of the evapotranspiration sources and (iv) the integration of the deep groundwater reservoir.

La maîtrise du transfert de nitrates sous les systèmes irrigués est un objectif primordial dans l’agriculture moderne. Celle-ci exige la recherche, surtout en plein champ, de conduire une stratégie optimale de fertigation. Dans ce but, un protocole expérimental sur une parcelle de 2 ha a été mis en oeuvre pour analyser le devenir de l’’azote sous différents scénarios d’irrigation et de fertilisation d’une culture de maïs. Dans l’articulation de ce travail, et pour pouvoir étudier la dynamique de l’azote en systèmes irrigués, nous avons tout d’abord réussi à définir et clarifier la relation ambigüe entre la méthode d’irrigation (irrigation gravitaire, par aspersion ASP, en goutte à goutte de surface GGS ou enterré GGE) et les différentes transformations de l’azote (Fixation, Minéralisation, Immobilisation, Nitrification, Dénitrification et Volatilisation). Cette relation, peu claire et non traitée dans d’autres études similaires, a été étudiée en mettant l’accent sur l’effet de certains facteurs, comme par exemple, l’humidité de sol et sa température, sur l’activité microbienne et donc sur les différentes transformations de l’azote (comme la minéralisation) et ce en mettant en avant la relation directe ou indirecte avec les méthodes d’irrigation. Une différence significative a été observée pour la minéralisation in situ entre les traitements sans aucun apport d’engrais menés sous les deux méthodes d’irrigation GGE et ASP. Une méthode manuelle d’analyse a été ensuite mise au point et validée pour déterminer la concentration en azote dans les échantillons de sol prélevés dans le cadre de ce travail. Cette méthode peu onéreuse pourrait être profitable aux agriculteurs. Les données issues de l’ensemble des traitements ont été utilisées pour modéliser les flux hydriques et azotés à l’aide de modèle HYDRUS-2D pour les systèmes par aspersion et en goutte à goutte enterré. L’analyse de sensibilité aux paramètres liés au transfert de nitrates du modèle de transfert a permis d’estimer la dynamique azotée pour d’autres contextes hydro-pédo-climatiques plus complexes. En conclusion, la présente thèse a permis d’améliorer la connaissance du fonctionnement de la fertigation en irrigation goutte à goutte enterré par comparaison avec l’aspersion, en milieu méditerranéen, en vue d’une diminution des entrants agrochimiques dans un contexte d’économie de la ressource en eau. / The main goal in modern agriculture is the control of nitrogen fluxes in agricultural soils under the irrigation techniques. This objective requires a lot of research, especially in the field, to escort an optimal strategy of fertigation. For this purpose, an experimental protocol has been applied to follow the soil nitrogen fate for various irrigation and fertilization scenarios, during two intensive field campaigns in maize plots. In the articulation of our work, and to be able to examine the nitrogen dynamics in unsaturated agricultural soils under irrigated systems, we succeeded firstly to determine and clarify the ambiguous relation between the irrigation techniques (flood irrigation, sprinkler irrigation, surface and subsurface drip irrigation) and the different nitrogen transformations (Fixation, Mineralization, Immobilization, Nitrification, Denitrification and Volatilization) in agricultural contexts. This relationship, which is unclear and untreated in other similar studies, has been reviewed by studying the impact of certain factors, such as soil moisture and soil temperature under different irrigation techniques, on microbial soil activity and therefore on the nitrogen transformations (such as mineralization). A significant difference of mineralization was observed in maize plots with no fertilizer application treatment between sprinkler irrigation and subsurface drip irrigation. The experimental data collected have been used to analyze the water and nitrogen fluxes for various initial conditions and fertilisation strategies under sprinkler and subsurface drip irrigation by using the HYDRUS-2D model. Analyzing the sensitivity of nitrogen fluxes parameters using HYDRUS-2D allowed to estimate the nitrogen dynamics under more complex agro-pedoclimatic contexts. In conclusion, the present study allowed to improve the fertilization knowledge under both the sprinkler and subsurface drip irrigation in a Mediterranean environment.

Advancements in computation and development of physically based hydrologic models to simulate complex vadose zone scenarios helped the research community to evaluate different scenarios easily compared to long-term field experiments. However, some field data collection is necessary to obtain input data such as soil properties, water usage and land management practices to validate the model performance specific to the site. Data obtained from field experiments conducted in 2011 at Hespler farms, Winkler, MB was used in this research for model calibration and validation. The hydrologic model, HYDRUS (2D/3D) was evaluated using parameters such as visual and statistical analysis. Model evaluation during the calibration and validation stage gave RMSE values of 0.019 and 0.015 cm3 cm-3; PBIAS values of -1.01 and -0.14, respectively, suggesting that the model was efficient in simulating soil water content similar to the field observed data. The validated models were then used to simulate outcomes for different scenarios such as 30-year rainfall data (1986 – 2015), different soil physical properties, and drainage system design parameters. Models simulating free drainage predicted lower soil water content compared to controlled drainage leading to 6 – 60 more trafficable days for 8 m spacing and 0.9 drain base depth. Free drainage predicted 8 – 110 additional trafficable days compared to controlled drainage for 15 m spacing and 1.1 drain depth. Heavier than normal rainfall events caused high water contents leading to a few years with a very low to no trafficable days under controlled drainage conditions. The comparisons are presented based on models using free drain conditions. Models with 8-m drain spacing predicted a 1 to 10-day increase in the number of trafficable days compared to the 15-m drain spacing. Drains placed at a base depth of 1.1 m below the soil surface predicted 4 - 40 more trafficable days compared to those installed at a base depth of 0.9 m. / October 2017

Intensive farming often leads environmental consequences. This is the case of the study area of this thesis: the Empordà, a region with a variety of intensive crops (fruits, cereals, forage,...) and manifest problems of groundwater pollution by nitrates whose origin points also to agricultural practices in the area. The work has focusen on monoculture production of corn for grain with furrow irrigation and mineral nitrogen fertilization. Within this framework, objectives has been defined as: (1) to evaluate the influence that irrigation and nitrogen fertilization have on production and environmental impacts (groundwater pollution by nitrates), and (2) to evaluate an implement simulation codes to deepen in knowledge of irrigation and crop management in the area. It has been defined an experimental test of two years on the same plot where five modules -with eight furrows each- of surface irrigation has been set for evaluating performance irrigation. On these modules has been sown corn and defined five different treatments -with three replicates each- resulting from the interaction of three doses of mineral nitrogen fertilizer (0, 210, and 500 kg N/ha) and two types of fertilizer: conventional (with two applications) an low release (with one application). The corn crop management was carried out according to standard practices in the study area. The experimental plot has been intensively monitored and sampled for monitoring and for quantifying all the variables that have influenced the behavior of irrigation and crop response to the treatments done. This information has also been used for to calibrate and/or to validate the RAIEOPT, EVASUP2, SIMRAIE, SIRMOD, HYDRUS, and STICS codes. The conclusions drawn from the results obtained on the irrigation system are: (1) first irrigation behaves very differently from other irrigations of the campaign, (2) the environment conditions where irrigation is developed are variable (furrow cross section, infiltration, soil compactation, and surface roughness) and influence on the behavior of irrigation, (3) the total dose of applied water did not exceed in any case 75% of the theoretical needs of the crop, (4) the simulation codes that best reflect observed irrigation behavior are RAIEOPT for calculating the average infiltration function and SIMRAIE for estimating doses of water infiltrated along the furrow, and (5) in the conditions experienced, the dose profiles of the infiltrated water along the furrows are practically flat. In terms of crop response to experimental scenarios tested is concluded that: (1) treatment with no application of nitrogen fertilizer has a grain yield of about 40% lower than the other treatments, (2) there are no differences in crop yield rates on treatments with some application of mineral fertilizer nitrogen, (3) the nitrogen leaching losses are associated with periods of drainage and are proportional to soil nitrogen content at the beginning of these periods, and (4) there has been no drainage during the two irrigation periods tested. Finally, on the simulation of soil-plant-atmosphere with STICS code is concluded that: (1) STICS is a useful tool for simulating the agricultural system in scenarios with and without crops, and (2) STICS tends to overestimate the risk of nitrate leaching observed in plot. / L’agricultura intensiva normalment porta associades conseqüències sobre el medi ambient. Aquest és el cas de l’àrea d’estudi de la present tesi doctoral: l’Empordà, una regió amb gran varietat de cultius intensius (fruiters, cereals, farratges,...) i amb problemes manifestos de contaminació d’aigües subterrànies per nitrats l’origen dels quals apunta, també, a les pràctiques agrícoles de la zona.El treball realitzat s’ha centrat en el monocultiu de blat de moro per a producció de gra amb reg per superfície en solcs i amb fertilització nitrogenada mineral. En aquest marc, s’han definit com a objectius (1) avaluar la influència que el reg i la fertilització nitrogenada tenen sobre la producció i l’impacte ambiental (contaminació subterrània per nitrats) i (2) avaluar i aplicar codis de simulació que permetin aprofundir en el coneixement del sistema de reg i el maneig del cultiu a la zona.S’ha plantejat un assaig experimental de dos anys de durada sobre la mateixa parcel•la experimental. En ella s’han configurat cinc mòduls de reg de 8 solcs cadascun per a l’avaluació del comportament del reg. Sobre aquests mòduls s’ha sembrat blat de moro i s’han definit cinc tractaments diferents (amb tres repeticions cadascun) fruit de la interacció de tres dosis de fertilitzant mineral nitrogenat (0, 210 i 500 kg N/ha) i dos tipus de fertilitzant: convencional (amb aplicacions de fons i de cobertora) i d’alliberació gradual (amb una aplicació de fons). El maneig del cultiu s’ha realitzat segons les pràctiques habituals de la regió.La parcel•la experimental s’ha monitoritzat i s’han pres mostres intensivament per a fer un seguiment i quantificar totes les variables que han influït en el comportament del reg i en la resposta agronòmica del cultiu als tractaments realitzats. Amb aquesta informació s’han calibrat i/o validat els codis de simulació RAIEOPT, EVASUP2, SIMRAIE, SIRMOD, LIXIM, HYDRUS i STICS.De l’anàlisi dels resultats obtinguts, sobre el sistema de reg per superfície es conclou que: (1) que el primer reg es comporta de forma molt diferent a la resta de regs de la campanya; (2) que les condicions del medi on es desenvolupa el reg són variables (secció transversal del solc, infiltració, compactació i rugositat del sòl) i influeixen en el comportament del reg; (3) que les dosis totals d’aigua aplicades no han superat en cap cas el 75% de les necessitats teòriques del cultiu; (4) que els codis de simulació que millor reflecteixen el comportament del reg observat són el RAIEOPT pel càlcul de la funció mitjana d’infiltració en solcs i el SIMRAIE per preveure les dosis d’aigua infiltrades al llarg del solc de reg; i (5) que, en les condicions experimentades, els perfils de les dosis d’aigua infiltrades al llarg dels solcs són pràcticament horitzontals.En quant a la resposta del cultiu als escenaris experimentals realitzats es conclou que: (1) el tractament sense aportació de fertilitzant nitrogenat té un rendiment en producció de gra de prop del 40% menor que la resta de tractaments; (2) no s’observen diferències en els índexs de rendiment del cultiu entre els tractaments amb alguna aportació de fertilitzant mineral nitrogenat; (3) les pèrdues de nitrogen per lixiviació van associades a períodes dedrenatge i són proporcionals al nitrogen present en el sòl a l’inici d’aquests períodes; i (4) no s’ha produït drenatge durant els períodes de reg assajats.Finalment, sobre la simulació del sistema sòl-planta-atmosfera amb el codi STICS es conclou que: (1) STICS és una eina útil de simulació del sistema agrícola en escenaris amb i sense cultiu; i (2) STICS tendeix a sobreestimar els risc de lixiviació de nitrats observat en parcel•la.

ABSTRACT Modeling of bark-, sand- and activated carbon filters for treatment of greywater Susanna Ciuk Karlsson   The part of the waste water produced in a household, originating from showers, dish - and wash water, is called greywater. It is possible to treat the greywater separately from the black water (toilet water) as it is less polluted and then use it for purposes such as garden irrigation. There are various methods for purifying greywater. Here, the possibility to purify greywater using three column filters with different materials (activated carbon, pine bark and sand) was examined through modeling in the computer program HYDRUS. A set-up with physical filters was available, where flow measurements were performed. These measurements were used to validate the model that was developed in HYDRUS. When a flow model had been produced that could replicate the measured flow, a module of HYDRUS was used to also model the reactive transport of nutrients and organic matter in the filters. The complete model was used for evaluation of the treatment performance of the filters during a default scenario where they were loaded with 1 liter of water per day containing pollutant concentration corresponding to typical greywater. / REFERAT Modellering av bark-, sand- och kolfilter för rening av BDT-vatten Susanna Ciuk Karlsson I ett hushåll används vatten som då blir till avloppsvatten. Detta avloppsvatten består till stor del av bad, disk och tvättvatten (BDT-vatten). Det är möjligt att behandla BDT-vattnet separat från klosettvattnet då det är mindre förorenat, låta det genomgå rening och sedan använda det för till exempel bevattning av trädgårdar. Det finns olika metoder för att rena BDT-vatten. Här studerades möjligheterna att rena BDT-vatten med hjälp av tre filter av olika material; aktivt kol, tallbark och sand, genom modellering i datorprogrammet HYDRUS. En praktisk experimentuppsättning med filterkolonner fanns att tillgå, där ett experiment med flödesmätningar genomfördes. Mätningarna användes för att validera modellen som utvecklades i HYDRUS. Efter att en flödesmodell som stämde överrens med uppmätta värden utvecklats, modellerades reaktiv transport av näringsämnen och organiskt material i filtren med en modul tillhörandes HYDRUS. Med hjälp av modelleringen kunde filtertypernas reningsförmåga utvärderas för ett iscensatt standardscenario där filtrena belastades med 1 l vatten/dag innehållandes föroreningar motsvarandes ett typiskt gråvatten.