Tesi sul tema "Water and nutrient use"
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Wang, Xin. "Linking Hydroperiod with Water Use and Nutrient Accumulation in Wetland Tree Islands". Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/531.
Testo completoKempen, Estelle. "Nutrient and water use of tomato (Solanum Lycopersicum) in soilless production systems". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97988.
Testo completoENGLISH ABSTRACT: Soilless production of crops relies on the addition of high concentrations of nutrients with the irrigation water. The drained nutrient solution should be re-used to reduce the risk of pollution and to increase the water- and nutrient use efficiency of the system. Besides the risk of pathogen build-up, one of the main impediments of a wider application of this method is the frequent analysis required to maintain optimum nutrient concentrations and ratios in the rootzone. Yield reductions may be caused by an unbalanced nutrient solution. Alternatively the addition level of nutrients can be calculated through the use of nutrient uptake models that simulate the change in the re-circulated nutrient solution. To simulate crop water and nutrient demand necessary for model based regulation it was necessary to quantify the key factors affecting nutrient uptake by plants. The nutrient solution concentration and ratios between the macro-nutrients affected the uptake of water and nutrients. The total nutrient uptake per root dry weight increased and more specifically the nitrate (NO3 -), phosphate (H2PO4 -), potassium (K+) and sulphate (SO4 2-) uptake increased with an increase in nutrient solution electrical conductivity (EC) from 0.8 to 4.0 mS cm-1 while water uptake decreased. Except for Ca2+ uptake there was no correlation between nutrient and water uptake. Nutrient uptake can thus not be calculated based on water uptake. Instead a mechanistic high-affinity Michaelis-Menten based model can be used to estimate macro-nutrient uptake (Un, mg m-2 hr-1). Water and nutrient uptake was also affected by the solar radiation levels. Since nutrient uptake is related to the growth rate, solar radiation levels can be expected to influence nutrient uptake. The uptake of all ions increased with an increase in the solar radiation levels and for NO3 -, K+ and H2PO4 - the uptake rate was higher at higher nutrient solution concentrations. The Michaelis-Menten based model was adjusted to incorporate the effect of solar radiation levels on nutrient uptake. Water uptake (Wu, L m-2 day-1) was simulated as a function of crop transpiration and crop leaf area using a linear regression model, but since leaf area development was affected by solar radiation levels this was additionally incorporated into the estimation of the leaf area index (LAI). The composition of the nutrient solution also affected the biomass allocation of the crop which can again affect nutrient use as well as the fruit yield. There was also a direct effect of nutrient solution composition on fruit yield and quality with higher EC’s resulting in smaller fruit but an increase in fruit dry matter %, total soluble solids (TSS), titratable acidity (TA) and lycopene content. The results in this thesis make a valuable contribution to our understanding of the effect of nutrient availability (concentration and ratios) and nutrient requirement for growth (solar radiation levels) on nutrient uptake. Incorporating these into nutrient uptake models resulted in the development of a handy tool to simulate changes in composition of re-circulating nutrient solutions ultimately resulting in an improvement of the water and nutrient use efficiency of soilless systems.
AFRIKAANSE OPSOMMING: Die grondlose verbouing van gewasse is afhanklik van toediening van voedingselemente teen hoë peile in die besproeiingswater. Die voedingsoplossing wat dreineer moet hergebruik word om die risiko van besoedeling te verminder en ook om die water en nutriënt verbruik doeltreffendheid van die sisteem te verbeter. ʼn Ongebalanseerde voedingsoplossing kan ʼn verlaging in opbrengste veroorsaak. Benewens die risiko van patogene wat opbou, is die gereelde analises nodig word vir die handhawing van optimale nutriënt konsentrasies en verhouding tussen elemente in die wortelsone een van die hoof faktore wat ʼn meer algemene gebruik van die metode verhoed. Alternatiewelik kan die nutriënt toedieningspeile bereken word deur voedingstof opname modelle en simulasie van die verandering in water en nutriente wat dreineer. Om ʼn model gebaseerde reguleringsmetode daar te stel was dit nodig om die belangrikste faktore wat nutriënt opname beïnvloed te kwantifiseer. Beide die konsentrasie van die voedingsoplossing en die verhouding tussen elemente het ‘n effek gehad op die opname van water en nutriënte. Die totale nutriënt opname per wortel droë massa het toegeneem. Terwyl water opname afgeneem het met ‘n toename in die elektriese geleding (EG) van die voedingsoplossing vanaf 0.8 tot 4.0 mS cm-1 het die nitraat (NO3 -), fosfaat (H2PO4 -), kalium (K+) en sulfaat (SO4 2-) opname verhoog. Behalwe vir Ca2+ opname was daar geen korrelasie tussen water en nutriënt opname nie. Nutriënt opname kan dus nie bepaal word gebaseer op wateropname nie. Alternatiewelik is die gebruik van ʼn meganistiese hoë-affiniteit Michaelis-Menten-gebaseerde model voorgestel om die opname van makro-nutriente (Un, mg m-2 hr-1) te bepaal. Water- en voedingstofopname is beinvloed deur die ligintensiteit vlakke. Voedingsopname word bepaal deur die groei van die plant, daarom is dit verwag dat ligintensiteit vlakke die opname van voedingstowwe sal beïnvloed. Die opname van al die ione het toegeneem met 'n toename in die ligintensiteit vlakke en die tempo van NO3 -, K+ en H2PO4 - opname was hoër by 'n hoër voedingsoplossing konsentrasie. Die Michaelis-Menten gebaseerde model is aangepas om die effek van ligintensiteit vlakke op nutriënt opname te inkorporeer. Opname van water (Wu, L m-2 dag-1) is gesimuleer as 'n funksie van transpirasie en blaaroppervlakte met behulp van 'n lineêre regressiemodel en aangesien die blaaroppervlak ontwikkeling ook deur ligintensiteit vlakke beïnvloed word, is dit opgeneem in die skatting van die blaaroppervlakte-indeks (LAI). Die samestelling van die voedingsoplossing het die biomassa verspreiding beïnvloed. Dit kan nutriënt gebruik en vrug opbrengs beïnvloed. Die voedingsoplossing samestelling het vrug opbrengs en - kwaliteit beinvloed met kleiner vrugte, maar 'n toename in droëmateriaal %, totale oplosbare vastestowwe (TOVS), titreerbare suur (TA) en likopeen inhoud by ʼn hoër EG. Die resultate in hierdie tesis lewer 'n waardevolle bydrae tot ons begrip van die effek van nutriënt beskikbaarheid (konsentrasie en verhoudings) en voedingstof behoefte vir groei (ligintensiteit vlakke) op voedingsopname. Deur die inligting te inkorporeer in voedingsopname modelle het gelei tot die ontwikkeling van 'n handige instrument om die veranderinge in die samestelling van hersirkulerende voedingsoplossings te simuleer. Dit lei gevolglik tot die verbetering van die water en voedingstof gebruik doeltreffendheid van grondlose stelsels.
Kerr, Barry Douglas. "Multiple Regression Equations to Estimate Mean Nutrient Concentrations in Streams of North Central Texas from Landsat Derived Land Use". Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc278778/.
Testo completoMir, Rigau Xavier. "Land Use Impact Assessment on the Nutrient Transport in the lake Mälaren". Thesis, KTH, Mark- och vattenteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170450.
Testo completoStockholm regionen står inför kraftiga urbana förändringar och det förutses att befolkningsökningen kommer att bli den främsta drivkraften för storstadsregionerna kring Mälaren under de kommande årtiondena. En grundlig regional- och stadsplanering behövs för att bygga ett hållbart samhälle och skydda miljön. I detta sammanhang är Coupled Human and Natural Systems (CHANS) användbara verktyg för att skapa framtidsscenarier för hur urbanisering och markanvändningar kommer att påverka ekosystem och vattenresurser. CHANS verktyg möjliggör analys av komplexa mönster och processer som inte framgår tydligt vid separata sociala och naturvetenskapliga studier. Inom CHANS ramverk fokuserar detta examensarbete på hur befolkningstillväxt och markanvändning och de ändringear de medför påverkar ytvattenutsläpp samt näringstransport i Norrström avrinningsområden. I detta avseende studerades olika översiktsplaner av 26 kommuner i Stockholm-Mälardalen regionen för att bygga en markanvändning evolutionmodell fram till 2040. Det studerade scenariot utvärderade konsekvenser av förändringarna i urbaniseringen som beskrivs i de omfattande översiktplanerna på ytvatten och näringsämne transport. Verktyget som användes för att utföra detta examensarbete var PCRaster. Det är ett miljömodelleringsverktyg som tillåter behandling av stora distribuerade data och kan skapa spatiotemporala miljömodeller. I detta avseende fördelades modellen i tre delar. Först erhölls den temporala markanvändningsevolutionen efter uppgifter från kommunala översiktplaner. Därefter beräknades ytvattenutsläppen med CN-metoden. Slutligen byggdes den näringstransportmodellen med hjälp av riktlinjerna från PolFlow modellen och näringsbelastningen från HELCOM och TRK-projektet. Resultaten visar en ökning av de bebyggda stadsområdena från 3,3 % bebyggda under år 2005 till 4,2 % år 2040 för hela Norrström avrinningsområde, som innebär en ökning med 25 % av de bebyggda områdena. Beträffande flödet i ytvattnet visar resultaten en jätteliten ökning av flödet på grund av att det studerade området har en stor skala. Slutligen visar resultaten för näringsämnenstransport en ökning av näringsbelastningen vid utloppet av sjön Mälaren med 20 % kväve och 15 % fosfor.
Becnel, Audrey R. "Land Use and Water Quality Correlations in Miami-Dade, Florida". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1549.
Testo completoEdwards, Richard Reginald. "The potential for the use of willow (Salix spp.) in buffer zones for reducing nitrate and atrazine pollution". Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322361.
Testo completoTaylor, Richard Peter. "The use of treated brewery effluent as a water and nutrient source in crop irrigation". Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1021265.
Testo completoHoskins, Tyler Courtney. "Water and nutrient transport dynamics during the irrigation of containerized nursery crops". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48165.
Testo completoMaster of Science
Mack, Rachel E. "Best Management Practice Use and Efficacy for the Virginia Nursery and Greenhouse Industry". Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/84159.
Testo completoMaster of Science
Spooner, Daniel Ron, e n/a. "Nutrient, organic carbon and suspended solid loadings in two ICOLLs, NSW Australia : biogeochemical responses". University of Canberra. Resource, Environmental & Heritage Sciences, 2005. http://erl.canberra.edu.au./public/adt-AUC20070129.130745.
Testo completoCarey, Richard O. "Evaluating temporal and spatial land use influences affecting nutrient water quality in the Biscayne Bay Watershed, Florida". [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025165.
Testo completoCrane, Kristy Susanne. "Pressurized Hot Water: An Alternative Method of Nutrient Extraction and Subsequent Analysis for Use in Small-Scale Agriculture". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd495.pdf.
Testo completoCowan, Watts Cara Ailene. "Critical review of us environmental protection agency numerical nutrient criteria with respect to culturally significant waters as a designated use". Thesis, Oklahoma State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163015.
Testo completoThe Cherokee Nation, a Federally-recognized Tribal government in Northeastern Oklahoma lacks Tribal water quality standards for numerical nutrient standards based on baseline conditions in the Cherokee Nation. Lotic waters are of special significance in Cherokee Nation culture and ceremonies. Three water quality standard priorities within the Tribe include defining Culturally Significant Waters as a designated use, identifying Culturally Significant Waterbodies and determining applicable numerical nutrient standards. Culturally Significant Water as a designated use was defined based on community surveys. Twelve rivers and streams were identified as a portion of the Culturally Significant Waters of the Cherokee Nation based on a tribal community survey using a Use Attainability Analysis. To address excess nutrients in the Cherokee Nation, a total phosphorus numerical nutrient criterion was determined using data for Culturally Significant Water bodies, literature guidance and the US Environmental Protection Agency recommended nutrient criteria process for the respective Aggregate Nutrient Ecoregion. The Oklahoma Scenic Rivers criterion of 0.037 mg/L total phosphorus for a 90-day geometric mean was evaluated and determined not to be protective of Cherokee Nation’s Culturally Significant Waters. A total phosphorus criterion of 0.016 mg/L was recommended to protect Cherokee Nation Culturally Significant Waters from benthic algae greater than 100 mg/m2 Chlorophyll a.
Nishigaki, Tomohiro. "Improvement of Water- and Nutrient-Use Efficiency with Optimum Agricultural Management Practices in Upland Cropping Systems in Morogoro, Tanzania". Kyoto University, 2017. http://hdl.handle.net/2433/228243.
Testo completoCulumber, Catherine Mae. "Soil Nutrient Cycling and Water Use in Response to Orchard Floor Management in Stone-Fruit Orchards in the Intermountain West". DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5030.
Testo completoJacobs, Suzanne Robin [Verfasser]. "Assessing the impact of land use on water and nutrient fluxes in the South-West Mau, Kenya / Suzanne Robin Jacobs". Gießen : Universitätsbibliothek, 2018. http://d-nb.info/1160874921/34.
Testo completoJacobs, Suzanne [Verfasser]. "Assessing the impact of land use on water and nutrient fluxes in the South-West Mau, Kenya / Suzanne Robin Jacobs". Gießen : Universitätsbibliothek, 2018. http://d-nb.info/1160874921/34.
Testo completoAkshaya, Devendra Kumar. "IMPACTS OF LAND USE/LAND COVER AND SOIL ON WATER QUALITY IN THE UPPER LITTLE MIAMI RIVER SUB-BASIN THE UPPER LITTLE MIAMI RIVER SUB-BASIN". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1334693369.
Testo completoMadriñan, Max Jacobo Moreno. "Eutrophication Trend of Lakes in the Tampa Bay Watershed and the Role of Submerged Aquatic Vegetation in Buffering Lake Water Phosphorus Concentration". Scholar Commons, 2008. https://scholarcommons.usf.edu/etd/373.
Testo completoKabore, Bertin. "Investigations into soil nutrient and change in soil physical characteristics under complementary forage rotation in comparison to pasture systems for dairy cows". University of Sydney, 2009. http://hdl.handle.net/2123/5355.
Testo completoA investigation into soil nutrient and the change soil physical properties was carried out for three pasture systems for dairy cows; the complementary forage rotation (CFR) which comprised of brassica (Brassica napus )/clover (Trifolium resupinatum ) and maize (Zea mays) capable of achieving more than 40 t/ha, the typical intensive pasture (PI) with kikuyu grass (Penisetum clandestinum) over-sown with ryegrass ( Lolium multiflorum ) and the extensive system (PE); on two soil types (brown chromosol and black vertisol) . The study demonstrated that the CFR system was capable of doubling its yield by using similar fertilizers (N, P and K) and water inputs compared to these of the PI system resulting of greater nutrients (N and K) and water use efficiencies. Overall, the nutrient lost through runoff water was very limited for two intensive systems and nearly nil for PE system. Also similar trends were observed for soil physical properties in the intensive systems except for the topsoil (0-10 cm) where light acidification (P= 0.04) was recorded in the CFR probably due to the soil works before the maize sowing.
Kabore, Bertin. "Investigations into soil nutrient and change in soil physical characteristics under complementary forage rotation in comparison to pasture systems for dairy cows". Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/5355.
Testo completoCornelisen, Christopher David. "Nutrient Uptake by Seagrass Communities and Associated Organisms: Impact of Hydrodynamic Regime Quantified through Field Measurements and use of an Isotope Label". [Tampa, Fla. : s.n.], 2003. http://purl.fcla.edu/fcla/etd/SFE0000079.
Testo completoSutter, Lori A. "Effects of Saltwater Intrusion on Vegetation Dynamics and Nutrient Pools in Low-Salinity Tidal Marshes, Pamunkey River (Virginia, USA)". W&M ScholarWorks, 2014. https://scholarworks.wm.edu/etd/1539616868.
Testo completoRivera, Anamarie Elizabeth. "A Review of Reclaimed Water for Irrigation Use in an Urban Watershed". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6576.
Testo completoUhlenbrock, Kristan M. "Nutrient Distribution Effects from Freshwater Discharge at Franklin Lock and Dam (S-79) in 2005 and 2006 on the Caloosahatchee Estuary and San Carlos Bay, Fort Myers, Florida". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002877.
Testo completoMorris, Kay. "Salinity and nutrients : growth and water use of aquatic macrophytes under controlled and natural conditions /". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phm876.pdf.
Testo completoBeale, C. V. "Analysis of the radiation-, nutrient- and water-use efficiencies of the potential energy crops Miscanthus x giganteous and Spartina cynosuroides, grown under field conditions in S.E.England". Thesis, University of Essex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361035.
Testo completoVaughan, Matthew CH. "Shining light on the storm: Using high-frequency optical water quality sensors to characterize and interpret storm nutrient and carbon dynamics among contrasting land uses". ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1002.
Testo completoKostrzewski, Jennifer Marie, e Jennifer Marie Kostrzewski. "Quantifying seasonal variations in water source and nutrient concentrations: a catchment comparison in Valles Caldera National Preserve, NM, USA". Thesis, The University of Arizona, 2006. http://hdl.handle.net/10150/626915.
Testo completoHasnat, Abul, University of Western Sydney, of Science Technology and Environment College e School of Environment and Agriculture. "Soil-water use and irrigation scheduling under fruit tree-turf alley cropping system in Hawkesbury Area". THESIS_CSTE_EAG_Hasnat_A.xml, 2003. http://handle.uws.edu.au:8081/1959.7/614.
Testo completoMaster of Science (Hons) (Agriculture)
Bergsten, Steven J. "Certain Agave Species Exhibit the Capability to be Moderately Productive Under Conditions of High Salt and Drought Stress". BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3818.
Testo completoRoss, James Donald. "Influence of climate and land use on nutrient and bacterial dynamics in surface waters of the Lower Fraser Valley, British Columbia". Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/31057.
Testo completoScience, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate
Goward, Kelly J. "Relationship of nutrients and pesticides to landuse characteristics in three subwatersheds of the upper White River, IN". Virtual Press, 2004. http://liblink.bsu.edu/uhtbin/catkey/1286601.
Testo completoDepartment of Natural Resources and Environmental Management
Neves, AntÃnia Leila Rocha. "Irrigation of cowpea with saline water at different growth stages and their effects on the plant and soil". Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5227.
Testo completoA sensibilidade à salinidade varia com o estÃdio de desenvolvimento da cultura. O feijÃo-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiÃes semi-Ãridas do mundo. Avaliou-se o efeito da irrigaÃÃo com Ãgua salina, aplicada em diferentes estÃdios de desenvolvimento de plantas de feijÃo-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetiÃÃes. O feijÃo-de-corda foi cultivado no espaÃamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com Ãgua do poÃo (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Ãgua salina com CEa de 5,0 dS m-1, com aplicaÃÃo iniciada apÃs a germinaÃÃo e permanecendo atà o final do ciclo; T3 - Ãgua salina com CEa de 5,0 dS m-1, da semeadura atà 22 dias apÃs o plantio (DAP), correspondendo Ãs fases de germinaÃÃo e crescimento inicial, e Ãgua do poÃo no restante do ciclo; T4 - Ãgua salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo atà a prÃ-floraÃÃo), e Ãgua do poÃo nas demais fases do ciclo; T5 - Ãgua do poÃo da semeadura atà 42 DAP e Ãgua salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floraÃÃo e frutificaÃÃo). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossÃntese, transpiraÃÃo, condutÃncia estomÃtica, produtividade, partiÃÃo de matÃria seca, os teores, os totais extraÃdos e a distribuiÃÃo dos nutrientes na planta, a eficiÃncia nutricional, eficiÃncia no uso da Ãgua e o acÃmulo de sais no solo. A irrigaÃÃo com a combinaÃÃo de Ãgua do poÃo com Ãgua salina reduziu o acÃmulo de sais no solo, em relaÃÃo ao T2. O T2 reduziu as taxas de fotossÃntese e transpiraÃÃo, em relaÃÃo ao T1. O T3 provocou reduÃÃo das trocas gasosas somente na primeira mediÃÃo, enquanto, que similar aplicaÃÃo nos outros estÃdios (T4 e T5) nÃo provocou reduÃÃes significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduÃÃes significativas no nÃmero de vagens e na produÃÃo de sementes por planta, em relaÃÃo aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 nÃo afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleraÃÃo no ciclo reprodutivo da cultura. Os minerais foram extraÃdos pelo feijÃo-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extraÃÃo da maioria dos elementos analisados, com exceÃÃo do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporÃÃes pelos frutos. O T3 reduziu a eficiÃncia de utilizaÃÃo da maioria dos nutrientes. O T2 reduziu a eficiÃncia agronÃmica de utilizaÃÃo de N, P e K, entretanto nÃo afetou a eficiÃncia de utilizaÃÃo dos nutrientes extraÃdos pelas plantas.
The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants.
Johnson, David Richard. "Use of In-Stream Water Quality Measurements and Geospatial Parameters to Predict Consumer Surfactant Toxic Units in the Upper Trinity River Watershed, Texas". Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc6091/.
Testo completoSchroder, Jonathan H. "Soil moisture-based drip irrigation for efficient use of water and nutrients and sustainability of vegetables cropped on coarse soils". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0014283.
Testo completoSchaible, Candace J. "Assessing Homeowners' Lawn Management Practices and Preferred Sources of Educational Information". DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7041.
Testo completoKöhler, Iris [Verfasser], Johannes [Akademischer Betreuer] Schnyder, Margaret [Akademischer Betreuer] Barbour e Rainer [Akademischer Betreuer] Matyssek. "The interactive effects of rising atmospheric CO2 and nutrient supply on carbon and water relations in grassland ecosystems : an analysis of stable carbon isotopes and water-use efficiency in vegetation samples from the Park Grass Experiment / Iris Köhler. Gutachter: Margaret Barbour ; Rainer Matyssek ; Johannes Schnyder. Betreuer: Johannes Schnyder". München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1033403032/34.
Testo completoDoley, Todd Michael. "Maintaining a Nitrogen Cap for Virginia's Potomac River: The Contribution of Alternative Development Patterns". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/31142.
Testo completoMaster of Science
Voß, Anja. "Untersuchung und Modellierung der Stickstoff- und Phosphorumsatz- und Transportprozesse in mesoskaligen Einzugsgebieten des Tieflandes am Beispiel von Nuthe, Hammerfließ und Stepenitz". Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2007/1548/.
Testo completoThe main objective of this study was to investigate the nitrogen and phosphorus processes in the north-eastern German lowlands and to suggest sustainable management options concerning land use that could lead to a reduction in nitrogen and phosphorous emissions into the river network. In order to fulfil the basic requirements of water quality modelling on river basin scale, the hydrological processes had to be validated first. For this purpose the ecohydrological model SWIM was used. The simulations were carried out on a daily time step within the period 1991 - 2000. The results have shown that SWIM was able to reproduce adequately the hydrological processes within all investigation areas. Based on these hydrological simulations the nutrient processes were modelled with SWIM for the time period 1996 - 2000. It became obvious that the modelling approaches within SWIM, especially concerning the nutrient cycling processes in lowland watersheds, had to be modified. Thus, an ammonium pool including its transformations processes was added. In addition, leaching not only of nitrate but also of ammonium and phosphate throughout the whole soil profile is now possible. Thus all nutrients can be transported to the outlet of the watersheds by the flow components. It could be shown that with these modifications the model was able to reproduce well the nitrogen and phosphorus processes in the research areas. With the validated model further applications were enabled. In order to investigate the reason for the decreasing trend in the nutrient concentrations in the Nuthe River, nutrient simulations were performed for the period 1981 - 2000. The results show that the concentrations after 1990 have decreased mainly because of the reduction of emissions from point sources and sewage fields. Further simulations in order to gain more information about the different nutrient sources showed that nitrate basically originates from diffuse sources and ammonium as well as phosphorus from point sources. Especially parameters related to land use and management as well as the root depth of plants turned out to be very sensitive to model results. Concluding, different land use change scenarios were adapted. The calculation results demonstrate that almost all provided scenarios lead to a reduction in the emission rates. Applying those scenarios which consider all relevant aims and recommendations concerning the protection of resources the highest changing rates could be achieved.
Voß, Anja. "Untersuchung und Modellierung der Stickstoff- und Phosphorumsatz- und Transportprozesse in mesoskaligen Einzugsgebieten des Tieflandes am Beispiel von Nuthe, Hammerfließ und Stepenitz". Potsdam Universitätsverlag Potsdam, 2008. http://deposit.d-nb.de/cgi-bin/dokserv?id=3071462&prov=M&dokv̲ar=1&doke̲xt=htm.
Testo completoLabadz, Martin. "A catchment modelling approach integrating surface and groundwater processes, land use and distribution of nutrients : Elimbah Creek, southeast Queensland". Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/60017/1/Martin_Labadz_Thesis.pdf.
Testo completoLindner, Björn. "The black water loop : water efficiency and nutrient recovery combined /". Hamburg : GFEU, 2008. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016561528&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Testo completoStone, Harry James. "THE POLITICAL ECONOMY OF ECOLOGICAL RESEARCH: ANALYZING THE “TOTAL MAXIMUM DAILY LOAD” PROCESS IN THE UPPER MILL CREEK (CINCINNATI)". Oxford, Ohio : Miami University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1082567599.
Testo completoKwan, Cheuk Hung. "Biosensors for biological nutrient monitoring /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202004%20KWAN.
Testo completoDarrow, Brian P. "Effects of nutrients from the water column on the growth of benthic microalgae in permeable sediments". [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002431.
Testo completoDu, Plessis D. "Impacts of cage aquaculture on the farm dam ecosystem and its use as a multipurpose resource : implications for irrigation". Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/2206.
Testo completoSmall farm dams (< 20 ha) in the Western Cape Province provide adequate water conditions for intensive cage production of rainbow trout (Oncorhynchus mykiss). A major environmental concern of cage aquaculture, however, is the high inputs of nutrients via commercial diets and the subsequent eutrophication of the water source. Eutrophication can result in the degradation of the general water quality (increasing pH levels, oxygen depletion, increased hydrogen sulphide and free ammonia) and shifts in the phytoplankton structure (increased biomass, single species dominance). Deterioration of water quality will affect the success of the fish farming enterprise as well as the performance of irrigation equipment by increasing the risk of clogging and corrosion. Water quality, phytoplankton and zooplankton compositions were monitored at four sites from June 2005 to November 2006 to determine the effects of cage culture on the farm dam environment, its associated biota as well as irrigation water quality. The distribution of nutrients, nitrogen and phosphorus, was mainly influenced by the stratification and mixing regime of the water bodies. Nutrient concentrations increased during the winter mixing period while in the summer months, they seem to settle to the lower part of the water column. Nutrient concentrations of production sites and reference sites were comparable except for the ammonia levels that were significantly higher at the production sites. Phytoplankton corresponded with nutrient availability resulting in high biomass during winter. In terms of biomass, phytoplankton was approximately two times more abundant in production sites compared to reference sites. Assemblage dominance by cyanophytes (Anabaena circinalis, Microcystis spp.) was found more often in production sites, while reference sites were dominated by dinophytes (Ceratium hirundinella, Peridinium spp.). Zooplankton biomass concurred with high phytoplankton biomass in winter. Zooplankton assemblages in production sites sustained much higher biomass. Effects of cage culture on irrigation water quality are evident from increased algal biomass and shifts in species composition. These results indicated that at its present production level, cage culture had impacts on the farm dam environment and irrigation water quality. The most significant evidence was given by increased plankton biomass and single species dominance in production sites. However, these findings can not solely be ascribed to the introduction of aquaculture as various other factors may also contribute to the water quality of these ecosystems.
Miguntanna, Nandika Prasadani. "Nutrients build-up and wash-off processes in urban land uses". Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/31236/1/Nandika_Miguntanna_Thesis.pdf.
Testo completoJúnior, Cícero Renê Almeida Barboza. "Desenvolvimento de mudas de pinhão manso (Jatropha curcas L.) em tubetes e submetidas a diferentes níveis de déficit hídrico". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-23032012-102119/.
Testo completoWith the growing demand for alternative energy to meet the world, increasingly more clean and renewable sources are being used. In Brazil, the production of vegetable oils aimed at producing energy (biodiesel) is still incipient. Among the different species of oleaginous plants, jatropha (Jatropha curcas L.) has emerged as a great alternative in providing raw material for biodiesel production. Information on this crop are still scarce, especially in Brazil where they recently started research. The need for local information also emphasizes the importance of research with Jatropha. Based on these needs, the aim of this experiment was to analyze the technical viability production of jatropha seedlings irrigated by subirrigation system and develop an automated system management. The irrigation control was carried out from the weight variation of the vials with the seedlings because of water loss through evapotranspiration. In the process of weight control were used load cells, which monitored the weight variation of a set of vials called the control group. The experimental design was the completely randomized with four replications. The treatments were four levels of depletion of the maximum water holding capacity (MCRA) presented by the substrate (T1=20%, T2=40%, T3=60% e T4=80% da MCRA). To quantify the effects of the treatments were evaluated weekly the following characteristics of seedlings: height and diameter of the stem, leaf number and leaf area, and the production of fresh and dry shoot and root. The results show that treatment 2 was what stood out among the others, producing higher quality seedlings with greater dry matter accumulation and increased water consumption.
Murasko, Susan Mary. "Particulate carbon, nitrogen and phosphorus stoichiometry of south west Florida waters". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003036.
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