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Desde a época da colonização, a cana-de-açúcar apresenta-se como um dos principais produtos da agricultura brasileira e, além disso, trata-se de um tipo importante de biomassa energética, servindo como base para todo o agronegócio sucroalcooleiro, responsável por empregos diretos e indiretos em todo o Brasil. Do seu processo de industrialização são obtidos produtos, tais como: o açúcar, o álcool (anidro e hidratado), o bagaço e a vinhaça. Nesse sentido, diante do aspecto da aplicação da vinhaça em práticas agrícolas, pode-se dizer que sempre ocorre a sua associação com processos de impactos ambientais. Assim sendo, conduziu-se a presente pesquisa buscando-se monitorar a dinâmica, em diferentes tipos de solo, de componentes químicos presentes na vinhaça, bem como, elaborar curvas de distribuição de efluentes presentes na vinhaça. A pesquisa foi conduzida em área experimental do Departamento de Ciências Exatas da ESALQ/USP, em casa de vegetação, onde foram distribuídas 50 bombonas, em blocos casualizados. A vinhaça foi coletada na Usina Costa Pinto do grupo COSAN no município de Piracicaba/SP e as dosagens de aplicação foram: 100 m³ ha-1; 150 m³ ha-1; 200 m³ ha-1; 250 m³ ha-1 e 300 m³ ha-1. As espécies analisadas foram: nitrato e potássio, assim como, o pH, condutividade elétrica e cálcio. As curvas de distribuição de efluentes foram confeccionadas para obtenção dos parâmetros de transporte do nitrato (utilizando-se o FIA Flow Injection Analysis, para as análises químicas) e potássio (Fotômetro de chama, para as análises químicas). Diante dos resultados obtidos, observou-se que as concentrações do íon nitrato apresentaram variação no solo, encontrando-se valores entre 3,6 a 119 mg L-1, no solo arenoso, e entre 1 e 70 mg L-1, no solo argiloso. Em relação ao potássio foram encontrados valores pontuais de 4,4 a 171,2 mg L-1, no solo arenoso (principalmente na profundidade de 60 cm), e entre 0 e 30 mg L-1, no solo argiloso. As concentrações de cálcio apresentaram variação no solo, sendo encontrados valores pontuais de 1,98 a 64,45 mg L-1, no solo arenoso, e entre 2,6 e 86,5 mg L-1, no solo argiloso. Os valores tanto do pH quando da C.E apresentaram variações no solo, tendo um intervalo para o pH de 6,4 a 7,75 para o solo arenoso e de 4,8 a 7,32 para o solo argiloso e a condutividade elétrica ficou em torno de 0,3 a 2,3 dS m-1 para o solo arenoso e de 0,23 a 0,75 dS m-1 para o solo argiloso. Em relação à curva de distribuição de efluentes da vinhaça, no solo argiloso, observou-se que tanto o potássio quanto o nitrato houve um maior deslocamento das curvas de eluição para a direita quando comparados com o solo arenoso indicando que os íons potássio e nitrato foram retidos com maior intensidade no argiloso em relação ao arenoso. Portanto, concluiu-se que: a percolação dos íons está diretamente relacionada com o tipo de solo e com a concentração de vinhaça e que a movimentação dos íons deve ser estudada em longos períodos para mostrar melhor a sua movimentação no perfil do solo. / While sugarcane has been one of the main crops in Brazilian agriculture since the time of colonization, it is now also a major source of biomass energy, serving sugarcane agribusiness and being responsible for many direct and indirect jobs in Brazil. Industrial processing of sugarcane leads to such products as sugar, alcohol (both hydrated and anhydrated), pulp and vinasse. One concern about the application of vinasse to agricultural operations relates to possible environmental impacts of vinasse. Hence, the present research had as objective to monitor of the dynamics, in different soil types, of chemical components present in vinasse, and to measure breakthrough curves (BTC´s) of vinasse from repacked columns. The research was carried out at the experimental facility of the Department of Exact Sciences, ESALQ, USP, a protected environment containing 50 boxes arranged in a random manner. The vinasse was collected at the Usina Costa Pinto COSAN site in the municipal district of Piracicaba, SP, and applied at rates of 100, 150, 200, 250 and 300 m³ ha-1. The analyzed elements were nitrate and potassium, but measurements were also made of pH, electric conductivity and calcium. The BTC´s were used to provide estimates of the transport parameters of nitrate (using flow-injection analysis for the chemical analyses) and potassium (using a photometer for the chemical analyses). The measurements showed that soil nitrate concentrations varied between 3,6 to 119 mg L-1 in the sandy soil, and between 1 and 70 mg L-1 in the clay soil. Observed potassium concentrations were between 4,4 to 171,2 mg L-1 in the sandy soil (mainly at a depth of 60 cm), and between 0 and 30 mg L-1 in the clay soil. Calcium concentrations were found to similarly vary from 1,98 to 64,45 mg L-1 in the sandy soil, and between 2,6 and 86,5 mg L-1 in the clay soil. The values of pH furthermore varied between 6,4 to 7,75 for the sandy soil and between 4,8 to 7,32 for the clay soil, while the electric conductivity was between 0,3 to 2,3 dS m-1 for the sandy soil and between 0,23 to 0,75 dS m-1 for the clay soil. The vinasse BTC´s of the clay soil showed that both potassium and nitrate were displaced considerably to the right (to higher pore volumes) as compared with the sandy soil. This indicates that the potassium and nitrate ions were kept (adsorbed) much stronger by the clay relative to the sandy soil. Ion transport rates hence were found to be a function of soil type. Results suggest that the transport of ions from the vinasse is best studied over relatively long periods of time, also in field soil profiles, to better show the long-term dynamics in the subsurface

Orientador: Ladaslav Sodek / Tese (doutorado) - Universidade Esstadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T18:53:51Z (GMT). No. of bitstreams: 1 Lanza_LucianaNunesMenolli_D.pdf: 7782960 bytes, checksum: 92b0ce21151564c79758f7150c4afd6d (MD5) Previous issue date: 2011 / Resumo: A soja é a leguminosa de maior importância econômica no Brasil com produção de 72,23 milhões de toneladas na safra de 2010/2011. O cultivo de soja em regiões que sofrem alagamento é uma das principais causas de perda de produtividade no Brasil. Nestas condições, ocorre redução na taxa de oxigênio do solo, e o sistema radicular da planta entra em hipoxia prejudicando o desenvolvimento e a produtividade das plantas. Existem evidências de que a adição de nitrato em condições de alagamento do sistema radicular (hipoxia) promove tolerância ao estresse, entretanto os mecanismos bioquímicos que envolvem essa tolerância ainda não estão totalmente elucidados. Analisando as alterações no metabolismo de nitrogênio em hipoxia, em plantas submetidas a diferentes condições experimentais, observou-se redução do conteúdo de nitrato dentro da planta, aumento no teor de aminoácidos solúveis totais, aumento na composição dos aminoácidos livres: Ala e Gaba, e redução de Asn, em plantas não noduladas e noduladas, além de redução no conteúdo de ureídeos totais em plantas noduladas. A adição de nitrato promoveu maior conteúdo de nitrato nas raízes, seiva do xilema e nódulos, maior teor de aminoácidos solúveis totais, maior conteúdo de proteínas solúveis totais nas raízes e menor nas folhas. A atividade da enzima redutase do nitrato in vivo em condições de hipoxia reduziu nas raízes das plantas não noduladas e nas raízes e folhas das plantas noduladas. A inclusão de K15NO3 no meio demonstrou que o nitrato é, de fato, absorvido em condições de hipoxia, pois as raízes, folhas e nódulos todos incorporaram o 15N. Entretanto, absorção do nitrato sob hipoxia foi bem menor do que sob normoxia. Tanto em normoxia como hipoxia as raízes apresentaram o maior grau de enriquecimento com 15N enquanto que a incorporação nos nódulos foi menor. Houve incorporação de 15N em aminoácidos em todos os tecidos, o que permite concluir que o nitrato não é apenas absorvido pelas raízes sob hipoxia mas também assimilado e transportado para a parte aérea. Os aminoácidos mais próximos ao processo de assimilação de nitrato, Asp, Glu, Ala e Asn, foram os que mais incorporaram o 15N. No entanto, em geral um grau menor de incorporação foi encontrado sob hipoxia. A adição de nitrato, no dia 7, na solução do vaso de cinco cultivares de soja cujo sistema radicular estava alagado promoveu, na cultivar IAC Foscarin-31, maior crescimento da planta quando comparada às plantas com nitrato desde o início do experimento; na cultivar IAC-23, maior massa seca do sistema radicular; nas cultivares IAC-17 e IAC-18 foi evidenciado o mesmo crescimento da planta que as demais com nitrato; e na cultivar IAC-24, houve menor crescimento da planta. A adição também promoveu maior formação de aerênquima no caule, na raiz principal e adventícia, além de estimular a maior formação de raízes adventícias. Os dados sugerem que em condições de hipoxia, embora em quantidades bastante reduzidas e num processo mais lento, o nitrato é absorvido pelas raízes, sendo parte, convertida a aminoácidos e menos de 40% convertidos a nitrito, o qual é eliminado para o meio. A redução do nitrato via redutase do nitrato, passo inicial de sua metabolização, não é um passo limitante, uma vez que há produção de nitrito, produto da atividade da enzima. Com a adição de nitrato na solução do vaso de cinco cultivares de soja foram observadas tendências para suprir a ausência de nitrogênio e manter o desenvolvimento da plantas em condições de alagamento. A cultivar IAC Foscarin-31 e IAC-24 apresentaram crescimento geral da planta, sendo maior o crescimento observado na cultivar IAC Foscarin-31. Na cultivar IAC-23 houve maior crescimento do sistema radicular; na cultivar IAC-17, da parte aérea, assim como na IAC-18 / Abstract: Soybean is a legume of great economic importance in Brazil with a production of some 72.23 million tons (2010/2011 harvest). One of the main causes of diminished yields of the cultivars produced in Brazil is their cultivation in regions subject to flooding. Under such conditions reduced availability of oxygen in the soil leads to hypoxia of the root system which impairs plant development and yield. There is evidence that the presence of nitrate during flooding can improve tolerance to hypoxic stress. However, the biochemical mechanisms underlying this phenomenon have not been fully elucidated. After analysis of the changes in nitrogen metabolism that occur under hypoxia, in plants subjected to a variety of experimental conditions, it was observed that there was a reduction in plant nitrate content, an increase in total soluble amino acids, an increase in the relative abundance of free Ala, Gaba, and a reduction in Asn, in both nodulated and non-nodulated plants, as well as a reduction of ureides in nodulated plants. The addition of nitrate during flooding resulted in a higher nitrate content of the root, nodule and xylem sap. Total soluble amino acids and soluble proteins also increased in the root under these conditions but decreased in the leaf. Under hypoxia the in vivo nitrate reductase activity declined in the roots of non-nodulated plants and in both the roots and leaves of nodulated plants. The inclusion of K15NO3 in the nutrient solution confirmed the uptake of nitrate under hypoxia, since roots, leaves and nodules became labelled. However, uptake under hypoxia was much lower than that observed under normoxia. Under both normoxia and hypoxia the roots showed the highest degree of 15N enrichment while the nodules showed the weakest. Incorporation of 15N in amino acids of all tissues shows that 15NO3 was not only taken up by the roots under hypoxia but that it was assimilated and transported to the shoot. The amino acids considered closest to N assimilation, Asp, Glu, Ala and Asn, were the most highly labelled. Nevertheless, lower levels of incorporation were generally found under hypoxia. The addition of nitrate to the hydroponic nutrient solution of five soybean cultivars, 7 days after flooding the root system, stimulated greater growth of the cultivar IAC Foscarin-31 as compared to plants with nitrate from the beginning of the experiment. It also stimulated greater root dry mass of the cultivar IAC-23, produced a similar growth increase of cultivars IAC-17 and IAC-18 compared to those with nitrate from the beginning, but resulted in less growth for the cultivar IAC-24. The addition of nitrate also stimulated formation of adventitious roots as well as aerenchyma which formed on both the stem and the main and adventitious roots. The data show that under conditions of hypoxia, nitrate is taken up by the roots although at a much lower rate than under normoxia, and in part is assimilated into amino acids while nearly 40% is reduced to nitrite which is excreted to the surrounding medium. The reduction of nitrate by the enzyme NR, the first step of nitrate metabolism, does not appear to be limiting since large quantities of the reaction product, nitrite, accumulate. With the addition of nitrate to the flooding medium of five soybean cultivars there was a tendency to overcome the absence of nitrogen and maintain plant development under flooded conditions. Of the five cultivars studied, IAC Foscarin-31 and IAC-24 responded positively through overall plant growth, with Foscarin-31 showing the greatest growth. Cultivar IAC-23 responded with greater root growth while IAC-17 and IAC-18 presented greater shoot growth / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Orientadores: Adriano Luiz Tonetti, Bruno Coraucci Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo. / Made available in DSpace on 2018-08-20T18:04:49Z (GMT). No. of bitstreams: 1 PaixaoFilho_JorgeLuizda_M.pdf: 2379245 bytes, checksum: 00497843fd17605c51498a78155246f6 (MD5) Previous issue date: 2012 / Resumo: A geração de lodo de esgoto (LE) é uma característica intrínseca do tratamento das águas residuárias por processos biológicos. Aliado a isso, o aumento do número de estações de tratamento de esgoto tem demandado soluções para a disposição econômica e ambientalmente segura para o lodo gerado. Um sistema amplamente utilizado no Brasil para o tratamento de esgoto desde a década de 80 são as lagoas de estabilização, no entanto ao longo desses anos o lodo gerado nesse sistema não tem recebido atenção, devido a baixa produção per capita e seu longo tempo de residência na lagoa. Uma opção com grande destaque no cenário nacional para sua disposição é a aplicação do lodo na agricultura como fonte de nutrientes em culturas com elevada necessidade de fertilizantes, tal como a roseira. Portanto, o objetivo desse trabalho foi estudar a aplicação do lodo da lagoa facultativa primária da cidade de Coronel Macedo (Estado de São Paulo) na cultura de roseiras variedade 'Carola', avaliando os efeitos sobre o desenvolvimento da planta. O experimento foi instalado em uma área experimental do Departamento de Saneamento e Ambiente da Faculdade de Engenharia Civil, Arquitetura e Urbanismo (UNICAMP), no município de Campinas-SP. As roseiras foram plantadas em baldes de 20 L, sendo o lodo incorporado na camada superficial do solo. Os parâmetros avaliados foram: a massa seca das raízes (MSR), a massa seca da parte aérea (MSPA), volume das raízes, área das folhas (AF) e concentração de nitrogênio no tecido foliar (NTF). Também foi estudada a quantidade de nitrato lixiviado e a fração de mineralização (FM) do lodo. A quantidade de lodo aplicada foi baseada na necessidade de nitrogênio da cultura, de acordo com o cálculo proposto pela resolução CONAMA 375/06. Os tratamentos foram: T1 - tratamento testemunha absoluta, T2 - 12 Mg ha-1 de lodo em base seca (BS), T3 - 24 Mg ha-1 de lodo BS (dose calculada), T4 - 36 Mg ha-1 lodo BS e T5 - adubação mineral (100 kg N ha-1). O delineamento experimental foi em blocos casualisados, com seis repetições. Foi verificado que o aumento da dose de lodo aplicado na roseira aumentou a MSR, MSPA, AF e o NTF. O maior crescimento da roseira (MSR+MSPA) aconteceu nos tratamentos T4 e T5, com 93 e 104 g planta-1, respectivamente. Houve um incremento na MSR na aplicação de LE na dose recomendada pela norma, de 14,00 e 34,00 g planta-1 para T1 e T3 respectivamente. Na primeira análise a maior AF e NTF foi no T4 com 14,66 cm2 e 21,43 g kg-1. A lixiviação de nitrato foi de aproximadamente 5% do nitrogênio total aplicado para os tratamentos com lodo (T2, T3 e T4) e de 10% na adubação mineral (T5). A FM do lodo da lagoa facultativa, determinada em incubação aeróbia, foi de 40%, valor acima do sugerido para lodo digerido anaerobiamente pela norma brasileira (FM = 20 %). Deste modo, a aplicação de lodo de esgoto na cultura da roseira proporcionou aumento nos valores dos parâmetros observados e para o cálculo da aplicação do lodo da lagoa em estudo o FM deve ser de 40% / Abstract: The sewage sludge (SS) generation is an intrinsic characteristic of the treatment of wastewater by biological processes. Allied to this, the increasing number of wastewater treatment plants has demanded solutions for the economical and environmentally safe disposal for the SS. A widely system used in Brazil for the wastewater treatment since years 80's is the stabilization ponds, however over the years the sludge generated in this system has not received attention owing the low production per capita and to long residence time in the pond. An option with great emphasis on the national stage for their disposal is the application in agriculture as a source of nutrients in crops with high demand for fertilizers, such as the rose bush. Therefore, the aim of this work was to study the application of sludge from the facultative lagoon from city Coronel Macedo (São Paulo State, Brazil) in cultured rose variety 'Carola', assessing the effects on plant development. The experiment was installed in an experimental area of Department of Sanitation and Environment, Faculty of Civil Engineering, Architecture and Urbanism (UNICAMP) in Campinas-SP. The roses were planted in 20L buckets, the sludge being applied subsurface. The parameters evaluated were: root dry matter (RDM), the shoot dry mass (SDM), root volume, leaf area (LA) and nitrogen concentration in leaf tissue (NLT). Also studied was the amount of nitrate leaching and the mineralization fraction (MF) of the sludge. The amount of sludge was applied based on the need for nitrogen of the culture, according to the method proposed by CONAMA 375/06. The treatments were: T1 - absolute control treatment, T2 - 12 Mg ha-1 sludge on a dry basis (DB), T3 - 24 Mg ha-1 sludge DB (calculated dose), T4 - 36 Mg ha-1 sludge DB and T5 - mineral fertilizer (100 kg N ha-1). The experimental design was randomized blocks with six replications. It was found that increasing the dose of sludge applied to the rose bush increased the RDM, SDM, LA and NLT. The largest growth of the rose (RDM + SDM) occurred in treatments T4 and T5, with 93 and 104 g plant-1, respectively. There was an increase in the RDM in the application of SS in the dose recommended by the standard of 14.00 and 34.00 g plant-1 for T1 and T3, respectively. In the first analysis the largest LA and NLT was 14.66 cm2 and 21.43 g kg-1 in T4. Nitrate leaching was about 5% of total nitrogen applied to the sludge treatments (T2, T3 and T4) and 10% in mineral fertilizer (T5). MF the sewage sludge of facultative lagoon, determined by aerobic incubation, was 40% above the value suggested for anaerobically digested sludge by Brazilian standard (MF = 20%). Thus, the application of sewage sludge in the culture of rose provided to increase the observed parameters and for calculating the application of sewage sludge of facultative lagoons in agriculture MF should be 40% / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

Submitted in fulfillment of the degree of Master of Applied Science: Biotechnology, Durban University of Technology, Durban, South Africa, 2017. / Domestic wastewater contains a high nutrient load, primarily in the form of Carbon (C), Nitrogen (N), and Phosphorous (P) compounds. If left untreated, these nutrients can cause eutrophication in receiving environments. Biological wastewater treatment utilizes a suspension of microorganisms that metabolize this excess nutrient load. Nitrogen removal in these systems are due to the synergistic processes of nitrification and denitrification, each of which requires its own set of operating parameters and controlling microbial groups. An alternative N-removal pathway termed the anammox process allows for total N-removal in a single step under anoxic conditions. This process, mediated by the anammox bacterial group, requires no organic carbon, produces negligible greenhouse gases and requires almost 50 % less energy than the conventional process, making it a promising new technology for efficient and cost-effective N-removal. In this study, a sequencing batch reactor (SBR) was established for the autotrophic removal of N-rich wastewater through an anammox-centric bacterial consortia. The key microbial members of this consortia were characterized and quantified over time using molecular methods and next generation sequencing to determine if the operational conditions had any effect on the seed inoculum population composition. Additionally, local South African wastewater treatment plants were screened for the presence of anammox bacteria through 16S rRNA amplification and enrichment in different reactor types. A 3 L bench scale SBR was inoculated with active biomass (~ 5 % (v/v)) sourced from a parent anammox enrichment reactor, and maintained at a temperature of 35 °C ± 1 °C. The reactor was fed with a synthetic wastewater medium containing no organic C, minimal dissolved oxygen (< 0.5 mg/L), and N in the form of ammonium and nitrite in the ratio of 1:1.3. The reactor was operated for a period of 366 days and the effluent ammonium, nitrite and nitrate were measured during this period. The hydraulic retention time was controlled at 4.55 days from Day 1 to Day 250, and thereafter shortened to 1.52 days from Day 251 to Day 360 due to an increased nitrogen removal rate (NRR). During Phase I of operation (Day 1 to Day 150), the reactor performance gradually increased up to an NRR of ~160 mg N/day. During Phase II (Day 151 to Day 250), the overall reactor performance decreased with the NRR decreasing to ~90 mg N/day, while Phase III (Day 251 to Day 366) displayed a gradual recovery of NRR back to the reactor optimum of ~160 mg N/day. The accumulation of nitrate in the effluent during the latter parts of Phase II and Phase III, coupled with oxygen ingress (~2.1 mg/L) in the same period, indicated that it was not the anammox pathway that was dominating N-removal within the reactor, but more likely the second half of the nitrification pathway mediated by the nitrite oxidizing bacteria (NOB). This was further confirmed through molecular analysis, which indicated that the bacterial population had shifted significantly over the course of reactor operation. Quantitative PCR methods displayed a decrease in all the key N-removing population groups from Day 1 to Day 140, and a marginal increase in anammox and aerobic ammonia oxidizing bacteria from Day 140 – Day 260. From Day 300 onwards, NOB had started dominating the system, simultaneously suppressing the growth of other N-removing bacterial groups. Despite this, the NRR peaked during this period, indicating an alternative mechanism for ammonia removal within the reactor system. A total population analysis using NGS was also performed, which corroborated the QPCR results and displayed a population shift away from anammox bacteria towards predominantly NOB and members of the phylum Chloroflexi. The proliferation of aerobic NOB and Chloroflexi, and the suppression of anammox bacteria, indicated that DO ingress was indeed the primary cause of the population shift within the reactor. Despite this population shift, N-removal within the reactor remained high. New pathways have recently emerged which implicate these two groups as potential N oxidizers, with specific NOB groups showing the ability for oxidation of ammonia through the comammox process, and members of the Phylum Chloroflexi being capable of nitrite reduction. This could imply that an alternate pathway was responsible for the majority of N-removal within the system, in addition to the anammox and conventional nitrification pathways. Additionally, in an attempt to detect a local anammox reservoir, eleven wastewater systems from around South Africa were screened for the presence of anammox bacteria. Through direct and nested PCR-based screening, anammox bacteria was not detectable in any of the activated sludge samples tested. Based on the operating conditions of the source wastewater systems, a subset of three sludge samples were selected for further enrichment. After 60-110 days of enrichment in multiple reactor configurations, only one reactor sample tested positive for the presence of anammox bacteria. Although this result indicates that anammox bacteria might not be ubiquitous within every biological wastewater system, it is more likely that anammox bacteria might only be present at undetectable levels, and that an extended enrichment prior to screening is necessary for a true representation of anammox bacterial prevalence in an environmental sample. / M

L’agriculture intensive qui caractérise le bassin de la Seine depuis une cinquantaine d’années est basée sur la généralisation de l’usage des engrais de synthèse et des pesticides et la rupture de la complémentarité culture-élevage. Ce mode d’agriculture compromet aujourd’hui gravement la qualité des eaux souterraines et de surface, notamment par la contamination nitrique. La mise en œuvre d’alternatives qui permettraient de concilier production agricole et respect de la qualité de l’eau se heurte à beaucoup d’entraves, de nature techniques et sociales. Sur le plan technique, le manque de données de références et d’indicateurs rigoureux permettant d’évaluer les performances agronomiques et environnementales de systèmes agricoles alternatifs, est un frein majeur. Le premier objectif de cette thèse est donc de développer un cadre conceptuel solide pour évaluer ces performances en termes de capacité productive et de risque de lixiviation nitrique, à travers le bilan d’azote des sols. Nous avons tout d’abord établi, sur base d’une méta-analyse des données de la littérature, des relations robustes pour l’estimation de la quantité d’azote fixée par les légumineuses qui jouent un rôle essentiel dans la fertilisation des systèmes d’agriculture biologique. Nous avons alors pu étudier la relation fertilisation/rendement/surplus des systèmes agricoles, d’une part pour établir leurs trajectoires d’évolution dans 124 pays au cours des 50 dernières années à travers les données de la FAO, d’autre part pour comparer les performances agro-environnementales des principales rotations biologiques rencontrées dans le bassin de la Seine avec celles des rotations pratiquées en agriculture conventionnelle raisonnée. Nous avons enfin établi sur une base empirique la relation qui existe entre surplus, lixiviation et concentration des eaux de drainage sous terres arables et prairies permanentes. Nous montrons dans une seconde partie comment le cadre conceptuel d’analyse technique ainsi développé peut être utilement appliqué dans des territoires particuliers pour éclairer et orienter des logiques d’acteurs et crédibiliser certaines alternatives qui puissent nourrir une nécessaire transition vers des agrosystèmes plus durables. Une analyse détaillée de la situation des captages de la Plaine du Saulce, qui alimentent la ville d’Auxerre, et celle du champ captant de Flins-Aubergenville, qui fournit en eau potable l’Ouest parisien, est ainsi présentée. Des scénarios alternatifs, allant au-delà des simples aménagements de pratiques, sont proposés, en tenant compte du contexte géographique et hydrogéologique propre à chaque cas d’étude. / The intensive agriculture characterizing the Seine watershed since half a century is based on the generalization of the use of synthetic fertilizers and pesticides and by the rupture of the connection between crop and livestock systems. This system is nowadays compromising ground- and surface water quality, namely through nitrate contamination which mostly originates from agricultural losses. The implementation of technically proven and socially acceptable alternatives, allowing reconciling agricultural production and water quality preservation, encounters lots of obstructions of technical and social nature. From a technical point of view, sound reference data and rigorous indicators are lacking to assess the agronomical and environmental performance of alternative agro-systems. The first objective of this thesis is therefore to develop a sound conceptual framework to evaluate the productive capacity and the risk of nitrate lixiviation of agro-systems, through an improved version of the nitrogen soil surface balance. We first developed, based on a meta-analysis of the literature, robust relations to determine symbiotic nitrogen fixation by grain and forage legumes crops, which plays a central role in organic farming systems. We then could establish the relationship between total N fertilization, harvested yield and surplus of agro-systems, in order (i) to draw the trajectories of 124 countries over 50 years based on FAO data, and (ii) to compare the performance of the main organic crop rotations of the Seine basin and those of the conventional ‘reasoned’ agriculture. Finally, we established an empirical relationship linking N surplus, lixiviation and nitrate concentration in drainage water for arable land and permanent grassland. We show in a second part of this thesis how this conceptual framework of analysis can be useful in particular territories to highlight and guide stakeholder action, as well as to make more credible some alternatives which can feed the necessary transition toward more sustainable agro-systems. We analyze the situation of the drinking water abstraction areas of La Plaine du Saulce, supplying the city of Auxerre (Burgundy) as well as that of Flins-Aubergenville, supplying the western part of Paris agglomeration. We elaborate alternative scenarios for these regions, going much farther than the mere improvement of agricultural practices, and taking into account the peculiar geographical and hydro-geological context of each study case.

Continuous and reliable monitoring of contaminants in drinking water, which adversely affect human health, is the main goal of the Broward County Well Field Protection Program. In this study the individual monitoring station locations were used in a yearly and quarterly spatiotemporal Ordinary Kriging interpolation to create a raster network of contaminant detections. In the final analysis, the raster spatiotemporal nitrate concentration trends were overlaid with a pollution vulnerability index to determine if the concentrations are influenced by a set of independent variables. The pollution vulnerability factors are depth to water, recharge, aquifer media, soil, impact to vadose zone, and conductivity. The creation of the nitrate raster dataset had an average RMS Standardized error close to 1 at 0.98. The greatest frequency of detections and the highest concentrations are found in the months of April, May, June, July, August, and September. An average of 76.4% of the nitrate intersected with cells of the pollution vulnerability index over 100.

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