This dissertation explores the hydrologic controls on salinity within mangroves and lagoons at sites in Florida and Mexico. The main objective of this research is to better understand hydrologic controls on mangrove ecosystem structure and develop ideas that will be useful to land managers attempting to regulate and conserve these critical habitats. This study was conducted at sites in Ft. Pierce, FL and Costalegre on the central Pacific coast of Mexico. We examined controls on water levels and salinity in a mangrove on a carbonate barrier island along the Indian River Lagoon, east-central Florida. Spectral analysis of water levels showed that mangrove groundwater levels are not tidally influenced. Salinities vary spatially, with values of ~10 in upland environments to ~75 psu in irregularly-flushed mangroves. Water chemistry indicates that water salinities are largely controlled by enrichment due to evapotranspiration. An electrical resistivity survey showed that the freshwater lens is restricted to uplands and that hypersaline waters extend deeply below the mangrove. These results indicate that evapotranspiration lowers water levels in the mangrove, which causes Indian River Lagoon water to flow into the mangrove where it evapoconcentrates and descends, forming a thick layer of high-salinity water below the mangrove. Spatial variability of terrain conductivity in the Ft. Pierce mangrove varied under two hydrologic management regimes, breached rotational impoundment management and rotational impoundment management. The difference in coefficient of variation (CV) between the breached RIM and RIM data was calculated to examine spatial variability in both the shallow and deep layers. A null-hypothesis model was employed to examine the statistical significance of the CV results. The average water levels were -0.06 m amsl and 0.49 m amsl during the breached-RIM and RIM regimes, respectively. The average shallow (EM31) layer terrain conductivity shifted slightly from 1868 mS m -1 to 1825 mS m-1 after the alteration in management regime, yet the standard deviation of these averages decrease from 656 mS m-1 to 216 mS m-1. The average deep (EM34) layer terrain conductivities were 328 mS m-1 and 255 mS m-1 during the breached-RIM and RIM regimes, respectively. The temporal CVs were 0.23 and -0.04 for the shallow and deep layers, respectively. The null-hypothesis model for the shallow layer illustrates that the difference in spatial structure is statistically significant. The deep layer CV was not statistically significant. These results indicate that the transition from breached RIM to RIM resulted in changes to both the physical and chemical hydrologic character of the impoundment, especially in the shallow layer. The second study sites were three mangrove communities along the central Pacific Mexican coast. Salinities varied by water type, with values of ~9 in La Manzanilla, ~17 in La Vena, ~33 in Barra de Navidad, ~0.4 in the fresh waters, and ~34 in the seawater. Sodium and Chloride concentrations and isotopic signatures, as well as salinity, were used as tracers in mass-balance mixing models to quantify estimates of relative fresh-water and seawater contributions to each site. La Manzanilla, a basin mangrove, had mean fresh-water contribution estimates of 63-84%. La Vena, a riverine mangrove, had fresh-water estimates of 39-51%. Barra de Navidad, a fringe mangrove, had low fresh-water contributions of 0-5%. These results illustrates that the role groundwater plays in mangrove hydrodynamics is dependent on the site hydrogeomorphology.

Restoration of Lithuanian independence, land reform, radically changed farming structure and strawberry growing potential has conditioned an increase of modern strawberry plantation. Irrigation is a rather important precondition for the commercial cultivation of fruit and berries in Lithuania. The new farm structure requires new, mainly small-scale irrigation systems. Strawberry water consumption and the soil water dynamics during strawberry growing period stated performing pilot research and additional yield which had been got because of the irrigation influence allows to measure optimal irrigation regime of the strawberry based on research. The aim of the work was to investigate dynamics of strawberry evapotranspiration in the Middle Lithuania and in the course of experiments, with respect to development peculiarities and productivity, to determine optimal irrigation regime for the strawberry grown in loamy soils. In the summary is presented strawberry evapotranspiration results maintaining optimal soil moisture conditions with irrigation; analysis of reference evapotranspiration methods; determination of their interaction degree and evaluation of the possibilities to introduce reference evapotranspiration models in calculation of the evapotranspiration of strawberries; quantitative evaluation of the influence of meteorological factors on the amount of the water consumed by strawberries and analysis of strawberry evapotranspiration calculation methods; evaluation of soil... [to full text]

Cotton plant growth and development, as well as monitoring nutrient use efficiency were evaluated using hydroponic approach. Two set of experiments were conducted to determine the influence of phosphorus (P), potassium (K) and PK and exogenous application of Indole-3-acetic acid (IAA), gibberellic acid (GA3), zeatin (Z) and their combinations on growth and development of cotton plants (Gossypium hirsutum) grown hydroponically. In the nutrient solution experiment, cotton vegetative growth was positively influenced by low P (half strength Hoagland standard solution), low K (one-sixth strength Hoagland standard solution) and high PK treatments (Hoagland standard solution). Phytohormone experiment negatively supported vegetative growth except root length at 43 days after transplanting (DAT). The nutrients levels applied significantly favoured NPK uptake by cotton plants while exogenous phytohormones application did not affect NPK uptake by cotton plants, except N uptake by stem. Low P and low K treatments estimated to have high nutrient use efficiency (NUE). For chlorophyll formation, low K and high PK significantly increased formation of chlorophyll a, b and total ab while the application of GA3, IAA, Z and IAA x GA3 x 2Z treatments significantly increased chlorophyll a, b and total ab at 80 DAT only. Low K and low P treatments stimulated endogenous phytohormone contents in the cotton plants. In the phytohormone experiment, cotton plants treated to IAA x GA3 x Z increased endogenous phytohormone contents in the cotton plants. Low P, low K, high PK treatments and phytohormones treatments significantly increased root area, root volume and root activity. Low P, low K and high PK treatments applied significantly influenced residual level of P and K in the hydroponics while phytohormone treatments did not affect residual level of P and K except at 43 DAT. Evapotranspiration rate was high at early and reproductive stages of plant growth. This report shows the response of mineral nutrients and phytohormones to support growth and development of cotton plants grown hydroponically. / Description as in abstract

Freshwater is a vital resource that circulates between the atmosphere, the land and the sea. Understanding and quantifying changes to the partitioning of precipitation into evapotranspiration, runoff and water storage change in the landscape are required for assessing changes to freshwater availability. However, the partitioning processes and their changes are complex due to multiple change drivers and effects. This thesis investigates and aims to identify and separate the effects of atmospheric climate change and various landscape drivers on long-term freshwater change. This is done based on hydroclimatic, land-use and water-use data from the beginning of the twentieth century up to present times and across different regions and scales, from catchment to global. The analyzed landscape drivers include historic developments of irrigated and non-irrigated agriculture and flow regulation. The thesis uses and develops further a data-motivated approach to interpret available hydroclimatic and landscape data for identification of water change drivers and effects, expanding the approach application from local to continental and global scales. Based on this approach development, the thesis identifies hydroclimatic change signals of landscape drivers against the background of multiple coexisting drivers influencing worldwide freshwater change, within and among hydrological basins. Globally, landscape drivers are needed to explain more than 70% of the historic hydroclimatic changes, of which a considerable proportion may be directly human-driven. These landscape- and human-driven water changes need to be considered and accounted for also in modeling and projection of changes to the freshwater system on land. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.</p> / VR, project 2009-3221

Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references. / Also available by subscription via World Wide Web / xiv, 177 leaves, bound ill., maps 29 cm

[Truncated abstract] Understanding the ecohydrological dynamics of native vegetation can provide a benchmark for future efforts to restore landscape hydrology and allow predictions of potential landscape responses to climate uncertainty and associated changes in vegetation cover. The key drivers of evapotranspiration (Et) involved in maintaining a hydrological balance that minimises deep drainage in semi-arid ecosystems operate at a range of scales, and in this thesis I assessed the water relations of functionally and taxonomically diverse plant communities in south-western Australia from the leaf-level to ecosystem scale. For three key communities; heath shrubland, mallee (small multistemmed eucalypt) -heath, and open eucalypt woodland, populating a typical catenary sequence of soil types along a slope, I addressed the following questions: 1) What are the predominant water use strategies of wheatbelt native plant communities and what underlying trade-offs determine the distribution of plant water use strategies along the topographical gradient? 2) What are the roles of soil water and hydraulic limitation in controlling the spatial and temporal dynamics of transpiration in different functional types? 3) What is the magnitude and partitioning of total Et in the woodland community and what processes determine Et fluxes on a seasonal and annual basis? 4) What are the seasonal differences in Et among contrasting community-types and how do these patterns relate to canopy attributes and transpiration capacity along the topographical gradient? A key philosophical step in working with species-rich communities was to develop the concept of 'hydraulic functional types' (HFTs) to identify groupings of species using associations of physiological and morphological traits that define their hydrological functioning. .... However, as shallow soils dried during spring and summer, Et fluxes were significantly lower at the heath site (0.35 versus 0.66 mm day-1 for the woodland in February), demonstrating that the seasonality of Et fluxes differentiates communityscale contributions to regional water balance. Land-surface exchange of water over native vegetation is by no means uniform, but varies according to the spatial and temporal availability of water along topographical gradients. In general, shallow soils present fewer opportunities for water use partitioning and favour drought hardiness and a transpiration response that tracks recent rainfall patterns, whereas deeper soils promote greater differentiation in water use strategy and support canopies responsive to atmospheric demand. This thesis provides a unique description of ecosystem water balance in a global biodiversity hotspot by viewing complex vegetation mosaics in terms of their relevant hydrological units. This information is fundamental to sustainable agroforestry and revegetation efforts and our ability to gauge possible changes in vegetation structure and function under a changing climate.

Diss. (sammanfattning Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The wastewater from the dairy cattle installations, when poorly managed, unleashes environmental impacts. Because of this, it requires the implementation of technological alternatives with a goal of maintaining environmental quality. Alternatively it is highlight the constructed wetlands, which are systems with low operational requirement designed for treatment of wastewater from various origins. The utilization of this technology, which aims to treat wastewater from the dairy cattle, has been intensified since 1998. Nevertheless, in Brazil there are few studies related to this type of wastewater. This study aims evaluating the applicability of constructed wetlands for the treatment of dairy cattle wastewater. In this study it was implanted two units of artificial wetlands post storage tank (area 116 m²), which receives effluent from a dairy production unit (daily production capacity of 140 liters milk). The constructed wetlands were operated in parallel and are characterized by a horizontal flow constructed wetlands - HFCW (surface area of 26.5 m²) and vertical flow constructed wetland (VFCW) (surface area of 14.3 m²). Both filters were excavated in the soil and water proofed, filled with coarse sand (d10 = 0.30 mm and d60 = 0.75 mm) as filter material and planted with macrophyte Typha domingensis Pers. The filters were fed under a hydraulic regime of 3.98 m³/week for HFCW and 4.5m³/week for VFCW. The treated effluent was infiltrated in the soil, through swales constructed in the experiment area. By physico-chemical and biological over 12 months was observed better performance related to the treated effluent in HFCW with average loading removal of 87% of COD, 81% BOD, 90% of SS , 80% TNK 80% NH4-N and 68% PO43-- P, respectively. To VFCW the obtained rates were 70% of COD, BOD of 52%, 70% of SS, 73% of TNK , 81% of NH4-N and 16% of PO43-- P, respectively. It was quantified an average evapotranspiration of 49% in HFCW, whereas the majors evapotranspiration rates occurred in months with higher temperature and in higher macrophytes foliar area. The greatest nutrient content found in the macrophytes occurred simultaneously with the highest growing velocities, which occurred in the beginning of plant development. The foliar tissue of HFCW was responsible for removal of 5.12% of the N load and 3.16% of the P load applied. In VFCW the macrophytes removed 0.88% of the applied N load and 0.30% of the applied P load. From the results obtained in this study recommends the use of constructed wetlands as an alternative technology to the treatment of wastewater originating from the dairy cattle facilities. / Os efluentes oriundos das instalações de bovinocultura leiteira, quando mal gerenciados podem promover impactos ambientais significativos, necessitando, portanto, da implantação de alternativas tecnológicas com vistas à manutenção da qualidade ambiental. Dentre elas destacam-se os filtros plantados com macrófitas FPM (wetlands construídos), os quais são sistemas com baixo requerimento operacional, projetados para atuar na depuração de efluentes de origens diversas. A utilização desta tecnologia voltada para o tratamento de efluentes produzidos em salas de ordenha de bovinocultura de leite vem sendo intensificadas desde 1998, contudo, no Brasil poucos são os estudos relacionados com este tipo de efluente. Este trabalho tem como objetivo geral avaliar a aplicabilidade de filtros plantados com macrófitas, empregados no tratamento do efluente de uma instalação de bovinocultura de leite. Implantou-se duas unidades FPM pós lagoa de armazenamento (área 116 m²), a qual recebe efluente proveniente de uma unidade produtiva leiteira (capacidade diária de produção de 140 litros de leite). Os FPM foram operados em paralelo e caracterizam-se, por um filtro plantado com macrófitas de fluxo horizontal FPMH (área superficial de 26,5 m²) e um filtro plantado com macrófitas de fluxo vertical FPMV (área superficial de 14,3 m²). Ambos os filtros foram escavados no solo, impermeabilizados, preenchidos com areia grossa (d10 =0,30 mm e d60 =0,75mm) como material filtrante e plantados com a macrófita Typha domingensis Pers. O FPMH operou sob um regime hidráulico de 3,98 m³/semana e o FPMV com 4,5m³/semana. O efluente tratado foi infiltrado no solo, através de valas de infiltração construídas no local. Por meio do monitoramento físico-químico e biológico ao longo de 12 meses, verificou-se maior desempenho de efluente tratado para o FPMH com eficiências médias de remoção em termos de carga de 87% de DQO, 81% de DBO, 90% de SS, 80% de NTK, 80% N-NH4 e 68% de P-PO43-, respectivamente. Para o FPMV as eficiências obtidas foram de 70% de DQO, 52% de DBO, 70% de SS, 73% de NTK, 81% de N-NH4 e 16% de P- PO43-, respectivamente. Foi quantificado uma evapotranspiração média de 49% para o FPMH, sendo que as maiores taxas de evapotranspiração ocorreram nos meses em que a temperatura e a área foliar das macrófitas foram maiores. Notou-se que os maiores teores de nutrientes no tecido foliar das macrófitas ocorreram simultaneamente com as maiores velocidades de crescimento das mesmas, que se deram no início do desenvolvimento das plantas. O tecido foliar das macrófitas do FPMH foi responsável por remover 5,12% da carga de N e 3,16% da carga de P aplicada no filtro, já no FPMV as macrófitas removeram 0,88% da carga aplicada de N e 0,30% da carga aplicada de P. A partir dos resultados obtidos nesse estudo recomenda-se a utilização dos FPM como uma alternativa tecnológica de tratamento de efluente liquido oriundo das instalações de bovinocultura de leite.

Made available in DSpace on 2015-04-17T14:55:20Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4002692 bytes, checksum: 85600be9b689a4e4048b5414df434ab6 (MD5) Previous issue date: 2012-08-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Studies related to litter dynamics are important to comprehend decomposing deciduos material, nutrients cycling, succession patterns, ecological disturbance and environmental variables interactions in terrestrial ecosystems. In opposition to Caatinga's degradation speed, a lack of studies related to litter production dynamics is observed. Thus, this study aimed to evaluate climatic factors (rainfall and evapotranspiration) and vegetation effects over temporal and spatial dynamics of litter production in Brazilian Northeastern's semiarid. A phytosociologic survey was performed in Paraiba's Cariri in 12 sampling areas. Two 1 m2 collectors (with 0,15 m3) were placed about 50 m distant from each other in order to estimate litter monthly production between November 2009 and 2011. Litter deposition values observed in this study varied between 3430 and 4600 kg.ha-1.year-1. Litter production was significantly bigger in the second year of survey and it varied between months in both years. Intra-annual variation was positive to total litter production, showing peaks of litterfall in dry period about three or four months after the greatest rates of monthly rainfall. While reproductive structures and branches corresponded to 14% and miscellany from 3% to 5%, leaves, which represented more than 60% of the total, corresponded to the predominant part of litter. Litter production was significantly different between areas so as each of its parts. The density of plant species, vegetation height and trunk diameter at ground were responsible for 79% of annual litter production in those different areas. Results reveal that litter production in Caatinga have a spatiotemporal heterogeneity, which is related to climate and vegetation and must provide effects over substratum in edaphic microorganisms activities and, consequently, in edaphic conditions and nutrients availability. Therefore, in Caatinga, associations of spatial variations in microhabitats conditions and inter-annual variations could interfere in the offering period of floral resource, substrate nutrients availability and, possibly, in the behavior of substrate-using animals. / Apesar do reconhecimento de que a fauna seja importante na ciclagem de nutrientes, as suas relações com a decomposição da serrapilheira ainda são pouco conhecidas em ambientes semiáridos. O objetivo deste estudo foi investigar o efeito espacial e temporal das condições do habitat e dos microartrópodes do solo sobre a decomposição na Caatinga. No Cariri paraibano, entre novembro de 2009 e outubro de 2011, a taxa de decomposição foliar foi avaliada através de dois transectos com 30 bolsas de serrapilheira, com 10±0,5 g de folhas de Caesalpinia pyramidalis e Croton blanchetianus, em igual proporção, distribuídos em 12 áreas de amostragem. No transecto denominado controle, as bolsas foram preenchidas apenas com folhas, enquanto no segundo transecto, denominado fauna-reduzida, além das folhas, as bolsas de serrapilheira apresentavam cerca de 30 bolas de naftalina (~33,2 g), para avaliação do efeito da fauna sobre a decomposição. No primeiro ano, a taxa de decomposição foi menor independentemente do período de exposição, sendo decomposto cerca de 32%, 47% e 63% em 120, 240 e 360 dias, respectivamente. Enquanto, no segundo ano, a perda de massa foi de 45%, 54% e 73%, respectivamente. A taxa de decomposição correlacionou-se com a precipitação (acumulada) e a evapotranspiração (acumulada). Analisando os efeitos da fauna de microartrópodes e de cada área de amostragem sobre a taxa de decomposição, verificou-se que estes fatores tanto atuam isoladamente, quanto de forma conjunta sobre esse processo, entre os diferentes períodos de exposição (120, 240, 360 dias). A riqueza de espécies, densidade, altura da vegetação e o diâmetro do tronco à altura do solo (DTS), a serrapilheira produzida e o efeito da fauna, juntas, explicaram 91% da taxa de decomposição anual da serrapilheira, porém o DTS foi à única variável não significativa neste modelo. A precipitação e ETR tem efeito chave sobre a decomposição, pois além de atuarem sobre as perdas por lixiviação de compostos lábeis solúveis em água, estes fatores influenciam a vegetação, a produção de serrapilheira e a fauna decompositora e, portanto, desencadeiam estímulos sobre diferentes fatores, que atuam sobre o processo de decomposição. Este experimento mostrou que a decomposição de plantas pode ser influenciada por fatores bióticos em uma Floresta Tropical Seca, como a Caatinga, e que a decomposição não pode ser explicada apenas pelo clima e pela qualidade do substrato, visto que no sistema solo-serrapilheira, a vegetação e os organismos edáficos são fatores críticos na manutenção e disponibilidade de nutrientes.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-14T13:09:45Z No. of bitstreams: 1 ALEXANDRA LIMA TAVARES - TESE (PPGMet) 2016.PDF: 1785379 bytes, checksum: 4abc947e5329e85eba74a25f6ab6e976 (MD5) / Made available in DSpace on 2018-08-14T13:09:45Z (GMT). No. of bitstreams: 1 ALEXANDRA LIMA TAVARES - TESE (PPGMet) 2016.PDF: 1785379 bytes, checksum: 4abc947e5329e85eba74a25f6ab6e976 (MD5) Previous issue date: 2016-02-26 / Capes / O estudo foi conduzido na Unidade de Produção de Hortaliças da empresa Hortaliças Vida Verde, em parceria com a Universidade Federal de Sergipe (UFS), localizado no município de Itabaiana, SE. O objetivo do trabalho foi determinar a evapotranspiração (ETc) e os coeficientes de cultivo (Kc) do coentro e da alface cultivados em clima tropical, bem como avaliar as variáveis fenométricas ao longo de seu ciclo de produção. A ETc das culturas foi obtida através do balanço hídrico no solo e a evapotranspiração de referência (ETo) pelo método de Penman-Monteith, utilizando-se dados coletados numa estação automática localizada próxima à área experimental. As variáveis fenométricas avaliadas foram: comprimento das raízes e caule, área foliar e peso da massa fresca da parte aérea. Os resultados da pesquisa evidenciaram que os valores médios da ETc do coentro e da alface são, respectivamente, 139,8 e 158,5 mm, nas condições de realização do experimento. O Kc médio do coentro encontrado foi 0,87 e da alface 0,84. Verificou-se que as culturas do coentro e da alface requerem mais atenção com a demanda hídrica no período do verão. Os resultados obtidos permitiram ainda constatar que o coentro e a alface no período de outono proporcionam melhor desenvolvimento de suas variáveis fenométricas, bem como suas produtividades, sendo portanto este o período mais apropriado para o cultivo dessas culturas em regiões tropicais. / The study was carried out in production unit of vegetabled of company Hortaliças “Vida Verde” in partnership with the Federal University of Sergipe (UFS), located in the city of Itabaiana, SE. The objective of this study was to determine the evapotranspiration (ETc) and crop coefficients (Kc) of coriander and lettuce grown in a tropical environment, as well as evaluating the fenometric variables throughout its production cycles. The ETc crops was determined based on soil water balance and reference evapotranspiration (ETo) by Penman-Monteith method (FAO/56), using collected dates from automatic weather station next to experimental site. The fenometric variables were: length of the roots and stem, leaf area and Fresh weight of shoot. The mean values of ETc for coriander and lettuce are, respectively, 139.8 and 158.5 mm while the mean values of Kc were 0.87 and 0.84 for coriander and lettuce, respectively. Results also show that coriander crop water needs are higher than lettuce during summer period. The results revealed that the coriander and lettuce in the fall period provide better development of their fenometric variables and productivity, which is the most appropriate period for the cultivation of these crops in the tropical regions.