Sökning: "cropland"

Visar resultat 1 - 5 av 20 avhandlingar innehållade ordet cropland.

  1. 1. Ecosystems in the Anthropocene: the role of cropland management for carbon and nitrogen cycle processes

    Författare :Stefan Olin; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon; Nitrogen; DVM; Ecosystem modelling; Cropland; Management; Yields;

    Sammanfattning : Through deforestation and conversion of natural ecosystems to croplands and pastures, have humans released vast amounts of carbon (C) dioxide (CO2) into the atmosphere. Roughly one third of the cumulative anthropogenic emissions until today stem from these practices, the remainder being mostly due to fossil fuel combustion. LÄS MER

  3. 2. Anthropogenic impact on predator guilds and ecosystem processes : Apex predator extinctions, land use and climate change

    Författare :Marianne Pasanen Mortensen; Bodil Elmhagen; Francisco Palomares; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Mesopredators; apex predators; top-down; bottom-up; interspecific killing; red fox; Eurasian lynx; grey wolf; wolverine; productivity; winter severity; cropland; zoologisk ekologi; Animal Ecology;

    Sammanfattning : Humans affect ecosystems by changing species compositions, landscape and climate. This thesis aims to increase our understanding of anthropogenic effects on mesopredator abundance due to changes in apex predator status, landscape and climate. LÄS MER

  4. 3. Food security in a changing climate : The role of cropland intensification and land acquisitions across Africa

    Författare :Altaaf Mechiche-Alami; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Agriculture; land grabbing; sustainability science; Network Analysis; Earth observation; Crop model;

    Sammanfattning : Food security is one of the world’s greatest challenges. The current food system shows an entanglement across the globe which means that local farmers reliant on subsistence agriculture no longer operate in isolation of larger-scale processes within the global economy or the changing biophysical system of the planet. LÄS MER

  5. 4. Pathways to future cropland : Assessing uncertainties in socio-economic processes by applying a global land-use model

    Författare :Kerstin Engstrom; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; land-use and land cover change; socio-economic modelling; scenarios; uncertainties;

    Sammanfattning : Global agricultural production almost tripled within the last five decades. The production increase wasbased on expanding cropland and pastures, as well as the intensification of agriculture, including increased use ofhigh yielding crop varieties, machinery, irrigation, artificial fertilisers, and pesticides. LÄS MER

  7. 5. Greenhouse gas fluxes from drained peatland : Measurement techniques and management impacts

    Författare :Hannes Keck; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Agricultural use of drained peatlands has significant implications for national greenhouse gas (GHG) emission inventories. Once drained, peatlands emit large amounts of carbon dioxide (CO2), may become small methane (CH4) sinks and, with nitrogen fertilisation, may emit large quantities of nitrous oxide (N2O). LÄS MER