Sökning: "nitrogen budget"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden nitrogen budget.

  1. 1. Assessing reactive nitrogen flows in European agricultural systems

    Detta är en avhandling från ; Chalmers tekniska högskola; Gothenburg

    Författare :Rasmus Einarsson; [2017]
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; food; nitrogen indicator; nitrogen budget; nitrogen; agriculture; nitrogen footprint; uncertainties;

    Sammanfattning : In most ecosystems, nitrogen is a scarce and growth-limiting nutrient. Natural and anthropogenic processes convert unreactive atmospheric dinitrogen (N2) into reactive, bioavailable, nitrogen. LÄS MER

  3. 2. Silicon cycling in the Baltic Sea Trends and budget of dissolved silica

    Detta är en avhandling från Linköping : Linköping University Electronic Press

    Författare :Liana Papush; Linköpings universitet.; Linköpings universitet.; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dissolved silica; trends; nutrient; nutrient ratios; diatoms; Redfield; limitation; eutrophication; riverine load; budget; fluxes; accumulation; retention; optimisation; Baltic Sea; Löst kisel; trender; näringsämne; näringsämnens kvoter; kiselalger; Redfield; tillväxtbegränsning; övergödning; flodtillförsel; budget; flöden; ackumulering; retention; optimering; Östersjön; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : The dissolved silicon (DSi) has a crucial role for growth of a large group of primary producers – diatoms and, hence, impact on functioning of the aquatic food web. This thesis contributes to an increased understanding of the modifications of the DSi cycling in the Baltic Sea. LÄS MER

  4. 3. Nutrient cycling in agroecosystems: nitrogen cycling in southern Sweden in the 1850s and two Tanzanian villages in the 1990s

    Detta är en avhandling från Lund

    Författare :Lars-Erik Williams; Lund University.; Lunds universitet.; [1999]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nutrient; nutrient model; nutrient cycling; nitrogen fixation; nitrogen budget; mixed system; miombo; manure; livestock; land use; historical system; food production; efficiency; crops; agroecosystem; carrying capacity; phosphorus; Scania; sustainability; Plant ecology; Växtekologi;

    Sammanfattning : This study presents a general model for analysing nutrient cycling in agroecosystems. The focus is on food production intensity, human carrying capacity, sustainability and efficiency. The model can be used on systems including different kinds of land uses, which makes it applicable for studies on different scales. LÄS MER

  5. 4. Carbon dynamics in spruce forest ecosystems - modelling pools and trends for Swedish conditions

    Detta är en avhandling från Stockholm : KTH

    Författare :Magnus Svensson; KTH.; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boreal; climate; CoupModel; net ecosystem production; nitrogen; process-based model; soil carbon; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : Carbon (C) pools and fluxes in northern hemisphere forest ecosystems are attracting increasing attention concerning predicted climate change. This thesis studied C fluxes, particularly soil C dynamics, in spruce forest ecosystems in relation to interactions between physical/biological processes using a process-based ecosystem model (CoupModel) with data for Swedish conditions. LÄS MER

  7. 5. Distribution and activity of nitrogen-fixing bacteria in marine and estuarine waters

    Detta är en avhandling från Växjö, Kalmar : Linnaeus University Press

    Författare :Hanna Farnelid; Linnéuniversitetet.; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mikrobiologi; Microbiology; 454-pyrosequencing; diazotrophs; heterotrophic bacteria; marine bacteria; marine microbial ecology; microbiology; nifH; nitrogenase; nitrogen fixation; PCR; qPCR;

    Sammanfattning : In aquatic environments the availability of nitrogen (N) generally limits primary production. N2-fixing prokaryotes (diazotrophs) can convert N2 gas into ammonium and provide significant input of N into the oceans. Cyanobacteria are thought to be the main N2-fixers but diazotrophs also include a wide range of heterotrophic bacteria. LÄS MER