Made available in DSpace on 2017-07-10T17:37:50Z (GMT). No. of bitstreams: 1 Loana Bergamo dos Santos.pdf: 1109658 bytes, checksum: 86a9ba08470cd16b7befaff7cd272ca6 (MD5) Previous issue date: 2011-03-30 / The constant search for sustainability of production systems have driven research to find alternatives to the problems arising from the intensification of production systems. In this context the present work was to study the effects of substitution of mineral nitrogen by chicken litter in oat and corn in succession and chemical characteristics of soil. Two experiments were conducted during the period from May 2009 to March 2010 in Oxisol area located at the experimental farm of the State University of Paraná, municipality of Rondon. The first test was conducted under a randomized complete blocks with eight treatments obtained from different combinations of chicken manure (applied in oat) and mineral N fertilization (applied in corn) and four replications. We studied the production of dry matter and nutrient accumulation in the straw of the oat crop, and yield components and yield of corn. In the second trial, after the corn harvest, we studied the chemical properties of soil under the design of randomized blocks in factorial scheme 8x3, with the eight combinations of fertilizer used in the first trial related to three depths of soil sampling (0 -5, 5-10 and 10-15 cm). Larger quantities of poultry litter in oat provided higher dry matter production and accumulation of N. All fertilization studied provided satisfactory average productivity for corn (8569 kg ha-1). The soil properties were changed with the use of poultry litter associated with mineral N fertilization. There was a decrease in pH, Ca, Mg, and increased the P, potential acidity, the cation exchange capacity and exchangeable Al with increasing proportions of poultry litter in relation to mineral N fertilization / A busca constante pela sustentabilidade dos sistemas de produção têm direcionado as pesquisas à buscar alternativas aos problemas oriundos da intensificação dos sistemas produtivos. Nesse contexto o presente trabalho teve como objetivo estudar os efeitos da substituição da adubação nitrogenada mineral pela cama de frango na cultura da aveia e do milho em sucessão e nos atributos químicos do solo. Foram conduzidos dois ensaios durante o período de maio de 2009 à março de 2010 em área de Latossolo Vermelho eutroférrico localizada na fazenda experimental da Universidade Estadual do Oeste do Paraná, município de Marechal Cândido Rondon. O primeiro ensaio foi conduzido sob o delineamento em blocos ao acaso com seis tratamentos obtidos a partir de combinações de quantidades crescentes de cama de frango aplicadas na aveia combinadas com a adubação nitrogenada mineral de cobertura aplicada no milho e quatro repetições. Estudou-se a produção de massa seca e acúmulo de nitrogênio pela cultura da aveia, e os componentes de produção e produtividade da cultura do milho. No segundo ensaio, após a colheita do milho, estudou-se os atributos químicos do solo sob o delineamento em blocos ao acaso em esquema fatorial 6X3, com as seis combinações de adubação utilizadas no primeiro ensaio associadas a três profundidades de amostragem do solo (0-5; 5-10 e 10-15 cm). A aplicação de cama de frango na cultura da aveia propiciou aumento da produção de massa seca e acúmulo de maior quantidade de N, enquanto a substituição de parte da adubação nitrogenada mineral pela cama de frango elevou os índices de produtividade da cultura do milho. Os atributos químicos do solo foram alterados pelos fatores estudados, ocorrendo a elevação dos teores de P, MO, Al trocável e acidez potencial, e redução do pH, K, Ca, Mg, soma de bases e saturação por bases.

Made available in DSpace on 2017-07-10T15:14:37Z (GMT). No. of bitstreams: 1 _Marcos_F_Martins.pdf: 1223784 bytes, checksum: 76c7bc7ba3e56163da07738160894089 (MD5) Previous issue date: 2016-02-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The aim of this study is to evaluate the rate of decomposition of straw on crambe cover crop based on no-tillage system under different soil management practices and usages. We attempt to approach the practice adopted by farmers in the western region of Paraná. The experiment was conducted in the experimental area of the Agronomic Institute of Paraná - IAPAR, regional center of Santa Tereza do Oeste, Paraná, Brazil. The experiment consisted of four soil management practices: Traditional Tillage System - SPDT - Scarified Tillage System - SPDE - Gypsum Agricultural Tillage System - SPDG - and Tillage System with Quality - SPDQ. The treatments were distributed in randomized order on portions subdivided on time with fifteen macro-plots of 20 m x 25 m. The assessments took place on 0 (zero), 7, 15, 30, 60, 90, and 120 days after the harvest of crambe. Decomposition was determined quantitatively by the analysis of the rate of decomposition of crop residues using litterbags. The average loss of phytomass of crambe crop was significantly different (p>0,05), specially for SPDE and SDPG, which had reduction of around 0,63% day-1 and 0,71% day-1, respectively. The longest half-life period was observed on system SPDQ-12, with 66 days. The shortest half-life period was observed on system SPDE, with 45 days. / O objetivo do presente trabalho foi avaliar a velocidade de decomposição da palha em cobertura da espécie do crambe em diferentes usos e manejos do solo com base no sistema plantio direto. Buscou-se aproximar da prática adotada pelos produtores rurais da região oeste paranaense. O experimento foi conduzido na área experimental do Instituto Agronômico do Paraná - IAPAR, pólo regional de Santa Tereza do Oeste, Paraná, Brasil. Os tratamentos foram constituídos de quatro sistemas de manejo do solo, sendo estes: Sistema Plantio Direto Tradicional - SPDT -, Sistema Plantio Direto Escarificado - SPDE -, Sistema Plantio Direto Gessado - SPDG -, e Sistema Plantio Direto com Qualidade - SPDQ. Os tratamentos foram distribuídos de modo inteiramente casualizados em parcelas subdivididas no tempo com quinze macro-parcelas de 20 m x 25 m. As avaliações no tempo ocorreram aos 0 (zero), 7, 15, 30, 60, 90 e 120 dias após colheita do crambe. A determinação da decomposição seguiu-se de forma quantitativa, por meio da análise da taxa de decomposição dos resíduos culturais com o uso de litter bags . A perda média de fitomassa da cultura do crambe foi significativamente diferente (p>0,05) principalmente para o manejo SPDE e SDPG, a qual tiveram reduções respectivamente de 0,63 % dia-1 e 0,71 % dia-1. Para o tempo de meia vida o maior tempo constatado foi no sistema tratamento que continha como manejo o consórcio composto de Aveia preta cabocla + Tremoço branco, com 66 dias, já o menor tempo de meia vida foi observado para o sistema SPDE, com 45 dias. O sistema de manejo influenciou no tempo de meia-vida dos resíduos reduzindo em até 21 dias.

Malgré l'importance reconnue des forêts tropicales humides dans la régulation du climat et du cycle global du carbone, la biogéochimie des forêts tropicales reste moins bien appréhendée que celle d'autres biomes. En particulier, il existe encore de larges incertitudes quant aux limitations nutritives des processus ou encore sur le rôle de la diversité pour les fonctions écosystémiques. La diversité spécifique élevée des arbres de forêt amazonienne se traduit localement par une forte hétérogénéité de la qualité des apports de litière foliaire, ces apports constituant une ressource primordiale d'énergie et de nutriments pour les organismes saprophages. Cependant les conséquences d'une telle hétérogénéité des litières pour le fonctionnement souterrain sont encore peu connues dans ce milieu. L'objectif de cette thèse est d'établir une compréhension mécaniste des effets de la qualité des apports de litière ainsi que du rôle de leur diversité sur la décomposition. J'ai combiné des fertilisations factorielles de carbone (C), d'azote (N) et de phosphore (P) à l'utilisation d'une large gamme de stœchiométrie C : N : P des litières (issues de différentes espèces d'arbres) en forêt tropicale de Guyane française et en laboratoire pour évaluer la nature et l'étendue des contraintes énergétiques et nutritives imposées par la qualité des litières sur les activités des décomposeurs. Bien que la perte en masse des litières dans ce système d'étude apparait largement expliquée par la qualité des différentes formes de C des litières, suggérant un fort contrôle de la disponibilité en énergie sur la décomposition, les ajouts externes de C n'ont pas permis de mettre en évidence cette apparente contrainte énergétique. Cependant, je montre que la décomposition des litières tropicales est limitée conjointement par N et P, et que l'amplitude de cette co-limitation est fortement reliée à la disponibilité en P des litières ainsi qu'à leur stœchiométrie N : P. Ainsi, même si le P apparaît plus profondément limitant dans ce système (en accord avec l'hypothèse généralement admise d'un fort déficit en P en forêt tropicale humide), l'accès à l'N foliaire semble également contraindre la décomposition. Je mets également en évidence des effets de diversité des mélanges de litières, pour la plupart synergiques (les taux de décomposition observés des mélanges étaient généralement plus élevés que ceux prédits à partir des taux de décomposition des espèces seules) et largement amplifiés par la présence de la faune détritivore. De plus, en présence de faune, il apparait qu'une forte dissimilarité stœchiométrique dans les mélanges de litières favorise des effets synergiques. Autrement dit, l'association de litières ayant des stœchiométries dissimilaires semble favoriser un meilleur équilibre nutritionnel pour la faune saprophage, stimulant ainsi la décomposition. Finalement, je montre que ces effets synergiques dans les mélanges sont renforcés à travers les effets à long terme des apports de litières issus des différentes espèces d'arbres contribuant à ces mélanges. Ce résultat suggère que la complémentarité de l'utilisation des ressources émerge à travers des interactions à long terme entre les arbres et les organismes décomposeurs. / The high tree species diversity in Amazonian rainforest translates into a high variation of leaf litter quality input to the soil. These inputs constitute a major resource of nutrients and energy for saprophageous organisms, particularly in tropical rainforests growing on old and highly weathered soils and consequently impoverished in rock-derived mineral nutrients. However the consequences of such leaf litter heterogeneity for belowground functioning are still poorly understood. In this thesis, I aim to develop a better mechanistic understanding of leaf litter quality effects and litter diversity on decomposition. Using a factorial fertilization of carbon (C), nitrogen (N), phosphorus (P) and a wide range of leaf litter C : N : P stoichiometries (derived from different tree species) in French Guiana rainforest and in laboratory, I aim to assess the nature and the extent of energetic and nutritional constraints imposed by litter quality on decomposer activities. Although the litter mass loss in this study system is greatly explained by the litter C quality, suggesting a strong control of energy availability on decomposition, external C additions do not alleviate this apparent energetic constraint. However, I find that litter decomposition is conjointly limited by N and P and that the extent of this NP co-limitation is widely related to leaf litter P content and to litter N : P stoichiometry. Thus, even if P appears more profoundly limiting in this system (in accordance to the well-recognized P deficiency hypothesis in tropical rainforest), the litter N access seems also constrain the decomposition. Moreover, I find significant litter diversity effects in litter mixtures and most of them are synergistics (observed mass loss in mixture was more often higher than predicted mass loss on the basis of single species decomposition). These litter diversity effects are largely higher in presence of soil fauna and increase with stoichiometric dissimilarity in mixtures. In other words, the association of stoichiometrically dissimilar litter appear promote a better nutritional balance for the saprophageaous fauna, and thus, stimulate the decomposition. Finally, I show that synergistic effects in mixtures are reinforced toward long-term presence of tree species contributing to the litter mixtures. This result suggest that complementarity effects on mixed litter decomposition may emerge through long-term interactions between aboveground and belowground biota.

L'évaluation écologique des cours d'eau ne prend pas en compte les différents processus qui y sont réalisés, faute d'indicateur disponibles. L'objectif de cette thèse a été de documenter l'utilisation de la décomposition des litières végétales d'origine terrestre comme indicateur de l'intégrité fonctionnelle des rivières de plaine et de piedmont suivies par l'Agence de l'Eau Adour-Garonne. Partie 1. Sur une douzaine de sites suivis pour la pollution par les pesticides, le taux de décomposition est divisé par deux entre le site le moins et le plus contaminé, entrainant le passage d'une décomposition co-assurée par les invertébrés et les microorganismes dans les sites les moins contaminés à un processus réalisé seulement par les microorganismes dans les sites les plus contaminés, compromettant le processus dans les rivières les plus contaminées. Cette altération est observée à des concentrations en pesticides pourtant inférieures aux seuils fixés par l'Union Européenne. Partie 2. Sur 58 sites qui maximisent l'amplitude des classes de qualité écologiques, l'absence de corrélation observée entre les indices biologiques basés sur les invertébrés (IBGN, I2M2) et les diatomées (IBD) et le processus de décomposition suggère que les perturbations, selon leur nature et/ou leur intensité, altèrent différentiellement la composition des communautés et les activité de transformation de la matière organique. Partie 3. Une grille d'évaluation de la qualité fonctionnelle des rivières croisant deux variables, ktotal et le ratio kinvertébré/kmicrobien est proposée à partir de 84 sites de suivi et de sites de référence tirés de la bibliographie. Cette grille montre qu'à l'échelle régionale, le processus de décomposition est plus affecté dans sa composante liée à l'activité des invertébrés qu'à celle liée aux microorganismes. En suivant les critères d'évaluation de la Directive Cadre sur l'Eau, cette grille d'évaluation met en évidence que seulement 28 % des sites étudiés atteindrait un bon état fonctionnel. Cette thèse a permit de documenter la réflexion menée sur le développement d'indicateurs fonctionnels et plaide pour l'inclusion de la décomposition des litières végétales dans l'évaluation évaluation écologique par une approche croisée, telle que formalisée par un graphique structure x fonction à double entrée. / The aim of this thesis was to document, at regional scale (SW France), the application of litter decomposition and associated metrics as a proxy of functional integrity of stream ecosystems. The Introduction exposed the underlying arguments, mainly relying on (1) the importance of this ecosystem process, which provides most carbon sources to the aquatic food web, and (2) the need to complement the structural metrics routinely used in biomonitoring schemes by a functional component. Chapter I dealt with the capacity, by using litter decomposition, to discriminate the effects of pesticides from other stressors in 12 agricultural streams selected along a contamination gradient. The decomposition rate was twice as low in the most contaminated site compared with the less contaminated one, and the relationship was monotonous along the gradient. Only the activity of invertebrate decomposers was affected, translating into the switch from a decomposition co-dominated by invertebrates and microorganisms in the less contaminated sites to a process only achieved by microorganisms in the most contaminated ones. Taxonomic richness and density of invertebrate decomposers together with a specific indicator based on invertebrate traits followed the same trends as the invertebrate-driven decomposition rate, kinvertebrate, while fungal biomass, sporulation rate and taxonomic richness remained unaffected. Consequently, the presence of pesticides compromised leaf breakdown, as microbial decomposers did not compensate for the invertebrate decomposers decline. This occurred while pesticides concentrations even in the most contaminated stream were under the European Union's Uniform Principles thresholds for targeted species. This study showed that litter breakdown, particularly the ratio of total to microbial-driven breakdown rate, is a pertinent proxy to assess the functional integrity of pesticide-contaminated streams. Chapter II compared the biological evaluation, as routinely undertaken in monitoring schemes from structural indicators based on invertebrates (IBGN and I2M2) and diatoms (BDI), with the functional indication based on litter decomposition. No correlation was found between structural and functional indicators on 58 streams, whereas the 3 structural indicators were strongly correlated each other. Redundancy analysis showed a negative relationship between ktotal or kinvertebrate and the proportion of cultures in the riparian corridor, while kmicrobial responded to the same environmental parameters (substratum coarseness, temperature) as structural indicators. The lack of correlation between invertebrate-based structural metrics and kinvertebrate suggested that disturbances, depending on their nature and/or intensity, differentially impair community composition and community activity in organic matter processing. In the view of proposing functional metrics, Chapter III concerned the distribution patterns of decomposition parameters on our study sites together with reference sites from the literature. Strong links were detected between decomposers community, decomposition rate and environmental settings, as exemplified by positive correlations between ktotal or kinvertebrate and detritivores abundance, kmicrobial and fungal biomass or sporulation rate, and the ratios ktotal/kmicrobial or kinvertebrate/kmicrobial and the abundance of decomposers. We propose a rating grid of stream ecosystem functional quality crossing two entries, ktotal and kinvertebrate/kmicrobial. At the regional scale, this grid shows that litter decomposition is more affected in its invertebrate component than in the microbial one. The Discussion exposes the main results in context and opens to perspectives, particularly about the question of reference sites. In conclusion, our results strongly argue for a crossed evaluation of ecological quality of running waters, as formalized by a chart with structure × fonction double entry.

Les cours d’eau de tête de bassin versant, malgré leurs tailles réduites, jouent des rôles importants pour le fonctionnement des milieux situés en aval, et rendent de nombreux services écologiques. Depuis l’émergence du River Continuum Concept, le fonctionnement de ces cours d’eau est considéré comme reposant principalement sur les apports allochtones de matière organique détritique par opposition aux écosystèmes aval de plus grande taille dans lesquels la production primaire autochtone est considérée comme prépondérante. Bien que les détritus soient, par définition, des ressources de moindre qualité pour leurs consommateurs que les végétaux vivants, le rôle des facteurs qui limitent la production biologique et les processus fonctionnels dans ces écosystèmes détritiques reste encore peu exploré. Par exemple la carence en éléments minéraux essentiels (notamment en azote et en phosphore) dans les détritus peut limiter le développement des organismes vivants dans les cours d’eau. De ce fait, la disponibilité en éléments minéraux dans la colonne d’eau, en stimulant la croissance, l’activité des décomposeurs et la qualité élémentaire des ressources par le processus d’immobilisation microbienne, pourrait contrôler pour partie les processus écologiques en jeu dans ces écosystèmes. En étudiant in situ la réponse des communautés microbiennes aux nutriments le long d’un gradient d’occupation des sols, nos travaux ont mis en évidence un effet positif des éléments dissous (N et P) sur la décomposition des litières et les activités enzymatiques des décomposeurs, et ce même pour les niveaux en nutriments les plus élevés du gradient, pour lesquels des effets inverses étaient attendus. Indépendamment, dans des cours d’eau anciennement soumis à de forts dépôts acidifiants, nous avons pu observer une récupération du processus de décomposition des litières. Néanmoins, cette restauration s’accompagnant d’un appauvrissement marqué en N, des perturbations du fonctionnement de ces cours d’eau pourrait se manifester à terme. Le rôle de la production primaire dans les cours d’eau de tête de bassin versant a ensuite été questionné. En effet, bien qu’étant mineur quantitativement, l’apport de carbone de forte qualité pourrait jouer un rôle non négligeable sur le fonctionnement des cours d’eau de tête de bassin versant. En particulier, l’importance et le rôle des apports en acides gras polyinsaturés (AGPI) via les biofilms phototrophes ont été questionnés. En se basant sur un suivi de terrain sur 15 cours d’eau des Vosges le long d’un gradient d’acidification, nos recherches ont tout d’abord pu mettre en évidence la présence de biofilms diatomiques riches en AGPI, malgré le caractère très forestier de ces cours d’eau. Dans un second temps, une expérience en conditions contrôlées a permis d’observer le rôle positif des apports, mêmes faibles, de ressources diatomiques sur la croissance et la survie du crustacé amphipode Gammarus fossarum. Sans cet apport, ces organismes se sont avérés incapables de maintenir leurs niveaux internes d’AGPI, suggérant qu’une consommation de producteurs primaires autochtones était indispensable à ces organismes détritivores. Nos résultats ont ainsi pu mettre en évidence les rôles fondamentaux que peuvent jouer la disponibilité en éléments dissous (N et P) et la qualité du carbone dans les ressources sur la production biologique et sur le processus de décomposition des litières dans les cours d’eau de tête de bassin versant. Ces résultats appellent désormais à investiguer plus profondément les interactions entre ces deux facteurs limitants, et à comprendre dans quels contextes l’un des facteurs pourrait suppléer l’autre. En particulier, il sera intéressant de rechercher comment diverses perturbations anthropiques (xénobiotiques, réchauffement climatique etc…) pourraient affecter l’intensité ou la nature de ces limitations / Despite their reduced sizes, headwater streams play important roles in the functioning of downstream ecosystems and provide numerous ecological services. Since the River Continuum Concept, the functioning of these streams has been considered as mainly relying on allochthonous supplies of detrital organic matter for their functioning, in contrast with downstream ecosystems of larger size where primary production is considered to be predominant. Despite that detritus represent, by definition, a resource of lower quality for its consumers than living plants, the nature of the factors limiting the biological production and functional processes in these detrital ecosystems remains sparsely explored. First, the lack of essential elements (in particular nitrogen and phosphorus) in detritus could be a major constraint for the development of living organisms in streams. As a result, the availability of mineral elements in the water column, by stimulating the growth and activity of decomposers, but also by increasing the elemental quality of resources through microbial immobilization, could control ecological processes in a higher extent than previously believed in these ecosystems. By studying in situ, the response of microorganisms to nutrients availability along a land-use gradient, our results have shown a positive effect of the dissolved elements (N and P) on the decomposition of leaf litters and the enzymatic activities of the decomposers, even for the highest nutrient levels of the gradient, for which adverse effects were expected. Independently, in streams formerly subjected to acidification, we observed a recovery of the process of leaf litter decomposition. Nevertheless, this recovery was accompanied by a marked N reduction in the ecosystem, huge changes in stream functioning might be expected in the medium to long term. The role of autochthonous primary production was then questioned. Indeed, while being quantitatively minor, this contribution of high quality carbon may play a significant role in the functioning of headwater streams. In particular, the importance and role of polyunsaturated fatty acid (PUFA) intakes via phototrophic biofilms was questioned. Based on a field survey of 15 rivers in the Vosges Mountains along an acidification gradient, our results first showed the presence of diatomic biofilms rich in PUFA, despite these streams are clearly in a forested context. In a second step, an experimentation carried out under controlled conditions permitted to observe the positive role of diatomic resources, even in low concentrations, on the growth and survival of the crustacean amphipod Gammarus fossarum. Without this input, these organisms were unable to maintain their internal levels of PUFAs, suggesting that the consumption of autochthonous primary producers might be essential for these detritivore organisms. All our results permit to highlight the fundamental roles that can be played by the availability of dissolved elements (N and P) and the carbon quality of the resources on the biological production and on leaf litter decomposition in headwater streams. These results stress the need for more profound investigation of the interactions between these two limiting factors, and for understanding in which contexts one factor could supplement the other. In particular, it will be interesting to investigate to what extent various anthropogenic disturbances (xenobiotics, global warming, etc...) could affect the intensity or the nature of these limitations

Thesis (MTech(Environmental Health))--Cape Peninsula University of Technology, 2018. / This study focuses on the assessment of the Green Zone Partnership Model (GZPM), which is a partnership project that was initiated by the City of Cape Town and Bonteheuwel community as a solution towards littering and illegal dumping in public open space areas. It is reported that the City of Cape Town is spending about R350 million year to remove waste illegally dumped in public open spaces around the city. In an attempt to assess the GZPM, the study has been used the environmental partnership theory as an approach to analyse the nature and significance of this partnership project. Over the last 20 years, following the emergence of the concept of sustainability, various organisations including governments are moving towards partnerships with various stakeholders as tools to finding solutions to environmental facing the planet (Long & Arnold, 1995). The emergence of this approach was the catalyst for a partnership formation to address the waste problem within the case study area (Ibid, 1995:34). To locate the study within the broader theoretical debate, the study draws on the theory of environmental partnership. Environmental partnership refers to the partnership formed to engage stakeholder partners in order to solve specific environmental problems. Similarly, Emas (2015:2) argues that partnerships encourage participatory decision making regarding the identification and solution of the current environmental problem. They are, to a larger extent, key to achieving the vision of sustainable development. In the South African context, the popular rise of a democratic system since 1994 has coincided with the escalation of various partnership projects, specifically formed to improve environmental quality. While there is a plethora of partnerships of this nature, with some initiated by the World Bank, IMF, and European Union; there is still a need to assess whether or not these partnership initiatives attain the desirable outcome(s). It is from this backdrop that this research seeks to assess the green zone partnership to establish whether or not it has improved environmental quality with specific reference to littering and illegal dumping in Bonteheuwel community The study used qualitative research design to answer the question raised in this research. Community survey and Face to face in-depth interviews with key stakeholder partners were conducted to collect data that which helped to answer the research question. This data was triangulated with other type of data collected from a household survey conducted within the study area. The data collected revealed how the partnership arrangement (GZPM) has improved the environmental and waste conditions in the communities. The results of the study will be crucial to the environmental health practitioners and managers dealing with waste related problems at local government level. The study has contributed to the existing knowledge in the field of environmental management, environmental health, waste management and natural resource management. Finally, the study concluded that partnership of this nature should be driven by champions from the communities to ensure that the environmental solution is sustainable for the benefit of the future generation. The fact that the partnership project was initiated and funded by the City of Cape Town does not guarantee as sustained solution toward a specific environmental problem (e.g., illegal dumping in public open space areas).

In a recent contribution in Nature (vol. 442, pp. 555-558) Austin & Vivanco showed that sunlight is the dominant factor for decomposition of grass litter in a semi-arid grassland in Argentine. The quantification of this effect was portrayed as a novel finding. I put this result in the context of three other publications from as early as 1980 that quantified photodegradation. My synopsis shows that photodegradation is an important process in semi-arid grasslands in South America, North America and eastern Europe.

No description available.

Magistro darbe tiriama pušies ir eglės kirtaviečių paklotės nariuotakojų kompleksų sukcesijos skirtingo ūkininkavimo sąlygomis Darbo objektas - Dubravos eksperimentinėje mokomojoje miškų urėdijoje (EMMU), Vaišvydavos g-joje 2006 m įrengtų 8 tyrimo barelių nariuotakojų kompleksai. Darbo metodas – statistinis nariuotakojų kompleksų tyrimas naudojant Barberio žemės gaudykles. Darbo rezultatai – Atliekant tyrimus nustatyta, kad Iš viso rasta 15 skirtingų nariuotakojų būrių ir klasių atstovų: du iš jų tinklasparniai (Neuroptera) ir blusos (Siphonaptera), rasti tik eglės kirtavietėje, be to blusos pirmą kartą rastos tik 2009 metais. Rasta ir 3(R) - retos rūšyss didysis puošniažygis (Carabus coriaceus) ir žalvarinis puošniažygis (Carabus nitens). Visų sistematinių grupių išskyrus Coleoptera, Aranei, Hemiptera, Orthoptera ir Blattoptera atstovų buvo aptikta daugiau eglyno barelyje, tai rodo, kad pušyno barelis turėjo geresnes sąlygas minėtiems nariuotakojams. Akivaizdūs paklotės nariuotakojų dominantai yra vabalai (Coleoptera), jų rasta virš 27 tūkstančių (2009 m.), jie užima ir daugiausia skirtingų gyvenamų nišų ir trofinių grupių.Visais 2009 metų tyrimų mėnesiais, išskyrus rugsėjį, didžiausias nariuotakojų skaitlingumas buvo eglės kirtavietėje. 2006-2009 metais didžiausias skaitlingumas buvo eglės kirtavietėje, o 2009 metais aptiktų nariuotakojų gausa pasiekė maksimumą. Didžiausias paklotės nariuotakojų skaitlingumas buvo miško bareliuose, mažiausias skaitlingumas buvo tuose... [toliau žr. visą tekstą] / Master thesis examined pine and spruce clear - cut litter arthropod complex succession of different forestry conditions Object of the work - Dubrava experimental teaching forestry enterprise (ETFE) Vaišvydava forestry in 2006 installed eight study plots arthropods complexes. Method of the work- statistical analysis of arthropod complexes using Barber ground traps. The results of the work - The study found that there were found 15 different classes of arthropods, and teams of representatives, two from the Neuroptera (Neuroptera) and flea (Siphonaptera), finding only in spruce clear - cut also flea first was discovered only in 2009. And there were found 3 (R) - rare species, the great ground beetle (C. coriaceus) and bronzed ground beetle (Carabus nitens). All systematic groups except the other than Coleoptera, Arana, Hemiptera, Orthoptera and Blattoptera were discovered more in spruce plot, which shows that the pine forest plot had better access to those arthropods. Obvious litter arthropod dominants are beetles (Coleoptera), they were found over 27 thousand (2009), and they occupy the most different niches and trophic groups. All months of 2009 trials, with the exception of September, had the highest levels of arthropods were in spruce clear - cut. In the period of 2006-2009 had the highest levels in spruce clear - cut, and in 2009 arthropod abundance reached a maximum. The highest number of litter arthropods was in forest plots, the lowest number was in those plots that had... [to full text]

Veterinary pharmaceuticals are routinely used in livestock production to treat diseases, prevent infections, and promote growth. However, the potential release of pharmaceuticals from agricultural activities has raised concerns because they may pose detrimental effects to the ecosystems and human health, for example fostering the evolution of antibiotic-resistant bacteria in the natural environment. A better understanding of the environmental fate of veterinary pharmaceuticals is critical to properly assess and mitigate their risks. This dissertation focuses on a major group of veterinary pharmaceuticals, ionophore antibiotics (IPAs), which is sold at over 4 million kilograms per year and constitutes more than one third of the total antibiotic consumption by the livestock industry in the U.S. Despite the extensive usage of IPAs, their environmental fate was not well-understood. Therefore, this study aimed at achieving a comprehensive understanding of the occurrence, persistence, and transformation of IPAs from poultry litter before and after applications to the agricultural lands. Three of the most commonly used members of IPAs were investigated in this study: monensin (MON), salinomycin (SAL), and narasin (NAR). Based on the common management practices of poultry litter, the potential abiotic and biotic transformation reactions of IPAs were examined under varying conditions relevant to the water-soil-litter systems. This dissertation consists of three sections. First, a robust analytical method was developed to quantify IPAs in various environmental compartments, especially in high organic-containing matrices such as poultry litter, and soil and runoff from litter-fertilized lands. Efforts were made to optimize the analytical method with respect to improving extraction recovery, reducing matrix effects, and validating a surrogate standard. Second, lab-scale experiments were set up to determine the chemical properties of IPAs in aqueous environments and to study the abiotic transformation of IPAs, including hydrolysis and photolysis. The results showed that IPAs are prone to hydrolytic transformation in acidic environments, which are likely to be encountered in acidic soils, alum-amended litter (alum: Al₂(SO₄)₃•12H₂O), and acidic runoff. Multiple transformation pathways were proposed based on the identified hydrolysis products. It is also noteworthy that the hydrolysis products of MON still exhibited a toxic effect on the selected microorganism (Bacillus subtilis). SAL and NAR were found to undergo direct photolysis under both UV light and sunlight irradiation. In natural water matrix, IPAs were also degraded by indirect photolysis with hydroxyl radicals generated by light-excited nitrate. Dissolved organic matter can shield IPAs from light and slow down their photolysis. Third, the biodegradation potential of IPAs was first tested in litter and soil microcosms. Factor analysis was conducted to delineate the interaction of water and temperature on IPA degradation in the litter. Litter-fertilized and non-fertilized soil microcosms were compared on the degradation of MON and SAL. Furthermore, the inhibition and biotransformation potential of IPAs were assessed under different redox conditions with litter-enriched cultures. Inhibition tests focused on examining IPAs’ impact on microbial community functions, including denitrification, sulfate-reduction, and methane production. Biodegradation tests were conducted with different electron acceptors, including oxygen, nitrate, sulfate, and organic carbons, with efforts to elucidate primary biotransformation products. On the basis of the results obtained in this study, several recommendations on litter management and IPA selection were made to help mitigate the release and transport of IPAs, as well as enhance their degradation. Overall, this study significantly improved the understanding of the environmental fate of IPAs and the obtained knowledge can aid proper selection of IPAs and management strategies in future applications to minimize the risks of antibiotic micropollutants in the environment.