Sökning: "semi arid"

Visar resultat 21 - 25 av 45 avhandlingar innehållade orden semi arid.

  1. 21. On-farm agrohydrological analysis of the Sahelian yield crisis : rainfall partitioning, soil nutrients and water use efficiency of pearl millet

    Författare :Johan Rockström; Jim Wallace; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Natural Resources Management; naturresurshushållning;

    Sammanfattning : Sub-Saharan Africa is presently experiencing a steadily aggravated food security crisis. This crisis is a result of a rapidly growing population combined with insignificant yield increases of the major cereal crops maize, millet and sorghum, during the last decades. LÄS MER

  3. 22. Land degradation and mitigation in northern China. Evaluated from the biological production

    Författare :Micael Runnström; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marklära; geomorfologi; Fysisk geografi; climatology; kartografi; klimatologi; cartography; pedology; desertification; China; GPP; Mu Us; LUE-model; overgrazing; Physical geography; geomorphology;

    Sammanfattning : Land degradation is commonly perceived to be severe in many parts of semi arid China. The transition towards market economy since the 1978 reforms, have set marginal dry lands under added pressure in the form of increased livestock numbers and expanding cultivation on erosive soils. LÄS MER

  4. 23. Phylogenetics of the genus sorghum, genetic diversity and nutritional value of its cultivated species

    Författare :Dickson Ng'uni; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Sorghum (Sorghum bicolor (L.) Moench) ranks fifth among cereal crops and second highest in production after maize in Africa particularly in the semi arid regions where it is a food security crop. LÄS MER

  5. 24. Unsaturated Solute Transport in a Semiarid Catchment - Nonlinear Analyses and Modelling

    Författare :Pernilla Öhrström; Avdelningen för Teknisk vattenresurslära; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; teknisk geografi; Hydrogeologi; teknisk geologi; unsaturated zone; Hydrogeology; geographical and geological engineering; solute transport; scaling; soils; semiarid regions; heterogeneity; preferential flow; fractals;

    Sammanfattning : Unsaturated solute transport is highly variable and therefore difficult to predict. In semi-arid areas, where water resources are limited, the presence of macropores is of great importance for crop production. The bromide ion (Br-) and dye tracers are useful for studies of water movement. LÄS MER

  7. 25. Stem canker and dieback disease on Grevillea robusta Cunn ex R. Br : distribution, causes and implications systems in agroforestry systems in Kenya

    Författare :Jane Wangu Njuguna; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : A widespread stem canker and dieback disease threatened the cultivation of Grevillea robusta on farms in Kenya. Disease index increased from 18% in the humid zone to 67% in the semi-arid zones and strongly correlated with altitude and length of drought period in the zones. LÄS MER